Merge branch 'de-gpl'

Issue template:Give stronger hints about sample input files
docs: mention that Ghostscript PDF/A can swallow hyperlinks
2020-08-12 12:20:38 -07:00 · 2020-08-12 12:12:37 -07:00 · 2020-08-12 12:12:00 -07:00 · 2020-08-12 11:40:42 -07:00 · 2020-08-07 02:23:21 -07:00 · 2020-08-07 02:21:02 -07:00
234 changed files with 11412 additions and 10055 deletions
@@ -11,8 +11,6 @@ concurrency =
 	multiprocessing
 source =
 	src/ocrmypdf
-omit =
-	tests/spoof/*

 [report]
 exclude_lines =
@@ -23,3 +21,4 @@ exclude_lines =
 	if 0:
 	if False:
 	if __name__ == .__main__.:
+	if TYPE_CHECKING:
@@ -1,6 +1,6 @@
 # OCRmyPDF
 #
-FROM ubuntu:19.10 as base
+FROM ubuntu:20.04 as base

 FROM base as builder

@@ -24,7 +24,7 @@ RUN \
 # Needs libleptonica-dev, zlib1g-dev
 RUN \
  mkdir jbig2 \
-  && curl -L https://github.com/agl/jbig2enc/archive/0.29.tar.gz | \
+  && curl -L https://github.com/agl/jbig2enc/archive/ea6a40a.tar.gz | \
  tar xz -C jbig2 --strip-components=1 \
  && cd jbig2 \
  && ./autogen.sh && ./configure && make && make install \
@@ -1,25 +1,44 @@
+# dotfiles
+.*
+!.coveragerc
+!.dockerignore
+!.git_archival.txt
+!.gitattributes
+!.gitignore
+!.pre-commit-config.yaml
+!.readthedocs.yml
+
+# Dev scratch
 *.ipynb
-*.pdf
-*.pyc
-*.rst
-*.sublime*
 **/*.pyc
-.*/
-!.git/
-.ruffus_history.sqlite
-bin/
-build/
-docs/
-dist/
-htmlcov/
-include/
-lib/
-MANIFEST.in
-ocrmypdf.egg-info/
-staging/
-tests/cache/
-tests/output/
+/*.pdf
+/*.qdf
+/*.png
+/scratch.py
+IDEAS
+log/
 tests/resources/private/
 tmp/
 venv*/
+/debug_tests.py
+*.traineddata
+/private
+
+# Package building
+*.egg-info/
+build/
+dist/
 wheelhouse/
+pip-wheel-metadata/
+
+# Code coverage
+htmlcov/
+
+# Docker specific
+bin/
+docs/
+include/
+lib/
+
+# Docker include .git/
+!.git/
@@ -0,0 +1,40 @@
+---
+name: Bug report
+about: Create a report to help us improve
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+**Describe the bug**
+A clear and concise description of what the bug is.
+
+**To Reproduce**
+What command line or API call were you trying to run?
+
+```bash
+ocrmypdf  ...arguments... input.pdf output.pdf
+```
+
+Run with verbosity or higher `-v1` to see more detailed logging. This information may be helpful.
+
+**Example file**
+Include an input PDF or image that demonstrates your issue.
+
+Please provide an input file with no personal or confidential information. At your option you may `GPG-encrypt the file <https://github.com/jbarlow83/OCRmyPDF/wiki>` for OCRmyPDF's author only.
+
+Links to files hosted elsewhere are perfectly acceptable. You could also look in ``tests/resources`` and see if any of those files reproduce your issue.
+
+(Exceptions: Issues with installation, command line argument parsing, test suite failures.Issues without example files usually cannot be resolved.)
+
+**Expected behavior**
+A clear and concise description of what you expected to happen.
+
+**Screenshots**
+If applicable, add screenshots to help explain your problem.
+
+**System**
+ - OS: [e.g. Linux, Windows, macOS]
+ - OCRmyPDF Version: ``ocrmypdf --version``
+ - How did you install ocrmypdf? Did you use a system package manager, `pip`, or a Docker image?
@@ -0,0 +1,17 @@
+---
+name: Feature request
+about: Suggest an idea for this project
+title: ''
+labels: enhancement
+assignees: ''
+
+---
+
+**Is your feature request related to a problem? Please describe.**
+A clear and concise description of what the problem is. Ex. I'm always frustrated when [...]
+
+**Describe the solution you'd like**
+A clear and concise description of what you want to happen.
+
+**Additional context**
+Add any other context or screenshots about the feature request here.
@@ -9,17 +9,16 @@ ocrmypdf  ...arguments... input.pdf output.pdf
 ```

 **Example file**
-Please include an example *input* PDF (or image). The input file is more helpful.
+Please include an example *input* PDF (or image). You could also try to use of the files in ``tests/resources/`` to illustrate your issue.

-Please check any or all that apply about the test file:
+Please check any or all that apply about the example file:

 - [ ] This is the input file
 - [ ] The file contains no personal or confidential information
- [ ] I am the copyright holder for this file
- [ ] I permit this file to be included in the OCRmyPDF test suite under the CC-BY-SA 4.0 license
- [ ] I am not the copyright holder, but this file is available under a free software license

-Files that are not free for inclusion in this project are quite welcome, but we like to collect free files for our test suite when possible. Please do *not* submit files with confidential information. At your option you may encrypt files for OCRmyPDF's author only.
+Please do *not* submit files with confidential information. At your option you may encrypt files for OCRmyPDF's author only.
+
+Issues submitted without an example input file are less likely to be resolved. The output file is generally not helpful.

 **Expected behavior**
 A clear and concise description of what you expected to happen. Include screenshots if applicable.
@@ -27,7 +26,7 @@ A clear and concise description of what you expected to happen. Include screensh
 **System:**

 - OS: [e.g. Linux, macOS]
- OCRmyPDF Version: [e.g. v7.4.0]
+- OCRmyPDF Version: [e.g. v10.3.0]

 **Additional context**
 Add any other context about the problem here.
@@ -1,47 +1,42 @@
-# Development environment
-.bash_history
-.pylintrc
-.pytest_cache/
-.ruffus_history.sqlite
-.venv*/
-*.pyc
-*.sublime-*
-*.DS_Store
-.mypy_cache/
+# dotfiles
+.*
+!.coveragerc
+!.dockerignore
+!.git_archival.txt
+!.gitattributes
+!.gitignore
+!.pre-commit-config.yaml
+!.readthedocs.yml
+
+# Dev scratch
+*.ipynb
+**/*.pyc
+/*.pdf
+/*.qdf
+/*.png
+/scratch.py
+IDEAS
+log/
+tests/resources/private/
+tmp/
+venv*/
+/debug_tests.py
+*.traineddata
+/private

 # Package building
-.eggs/
 *.egg-info/
 build/
 dist/
 wheelhouse/
 pip-wheel-metadata/

+# Code coverage
+htmlcov/
+
 # Automatically generated files
 docs/_build/
 docs/_static/
 docs/_templates/
 docs/Makefile
 ocrmypdf/lib/_*.py
-
-# Code coverage
-.coverage*
-htmlcov/
-
-# Testing
-.ipynb_checkpoints/
-.vscode/
-*.ipynb
-*.profile
-/*.pdf
-/*.qdf
-/*.png
-/scratch.py
-IDEAS
-log/
-tests/output/
-tests/resources/private/
-tmp/
-/debug_tests.py
-*.traineddata
-/private
@@ -1,6 +1,6 @@
 repos:
  - repo: https://github.com/pre-commit/pre-commit-hooks
-    rev: v2.4.0
+    rev: v3.1.0
    hooks:
      - id: check-case-conflict
      - id: check-merge-conflict
@@ -8,16 +8,16 @@ repos:
      - id: check-yaml
      - id: debug-statements
  - repo: https://github.com/asottile/seed-isort-config
-    rev: v1.9.3
+    rev: v2.2.0
    hooks:
      - id: seed-isort-config
  - repo: https://github.com/pre-commit/mirrors-isort
-    rev: v4.3.21 # pick the isort version you'd like to use from https://github.com/pre-commit/mirrors-isort/releases
+    rev: v5.0.5 # pick the isort version you'd like to use from https://github.com/pre-commit/mirrors-isort/releases
    hooks:
      - id: isort
  - repo: https://github.com/psf/black
-    rev: stable
+    rev: 19.10b0
    hooks:
      - id: black
-        language_version: python3.7
+        language_version: python3.8
        exclude: ^src/ocrmypdf/lib/_leptonica.py
@@ -3,15 +3,10 @@
 [![Build Status][azure]](https://dev.azure.com/jim0585/ocrmypdf/_build/latest?definitionId=2&branchName=master) [![PyPI version][pypi]](https://pypi.org/project/ocrmypdf/) ![Homebrew version][homebrew] ![ReadTheDocs][docs] ![Python versions][pyversions]

 [azure]: https://dev.azure.com/jim0585/ocrmypdf/_apis/build/status/jbarlow83.OCRmyPDF?branchName=master
-
 [travis]: https://travis-ci.org/jbarlow83/OCRmyPDF.svg?branch=master "Travis build status"
-
 [pypi]: https://img.shields.io/pypi/v/ocrmypdf.svg "PyPI version"
-
 [homebrew]: https://img.shields.io/homebrew/v/ocrmypdf.svg "Homebrew version"
-
 [docs]: https://readthedocs.org/projects/ocrmypdf/badge/?version=latest "RTD"
-
 [pyversions]: https://img.shields.io/pypi/pyversions/ocrmypdf "Supported Python versions"

 OCRmyPDF adds an OCR text layer to scanned PDF files, allowing them to be searched or copy-pasted.
@@ -30,8 +25,7 @@ ocrmypdf                      # it's a scriptable command line program

 [See the release notes for details on the latest changes](https://ocrmypdf.readthedocs.io/en/latest/release_notes.html).

-Main features
-------------
+## Main features

 - Generates a searchable [PDF/A](https://en.wikipedia.org/?title=PDF/A) file from a regular PDF
 - Places OCR text accurately below the image to ease copy / paste
@@ -47,8 +41,7 @@ Main features

 For details: please consult the [documentation](https://ocrmypdf.readthedocs.io/en/latest/).

-Motivation
----------
+## Motivation

 I searched the web for a free command line tool to OCR PDF files: I found many, but none of them were really satisfying:

@@ -62,8 +55,7 @@ I searched the web for a free command line tool to OCR PDF files: I found many,

 ...so I decided to develop my own tool.

-Installation
------------
+## Installation

 Linux, Windows, macOS and FreeBSD are supported. Docker images are also available.

@@ -87,8 +79,7 @@ brew install ocrmypdf

 For everyone else, [see our documentation](https://ocrmypdf.readthedocs.io/en/latest/installation.html) for installation steps.

-Languages
---------
+## Languages

 OCRmyPDF uses Tesseract for OCR, and relies on its language packs. For Linux users, you can often find packages that provide language packs:

@@ -105,8 +96,7 @@ pacman -S tesseract-data-eng tesseract-data-deu # Example: Install the English a

 You can then pass the `-l LANG` argument to OCRmyPDF to give a hint as to what languages it should search for. Multiple languages can be requested.

-Documentation and support
-------------------------
+## Documentation and support

 Once OCRmyPDF is installed, the built-in help which explains the command syntax and options can be accessed via:

@@ -118,35 +108,35 @@ Our [documentation is served on Read the Docs](https://ocrmypdf.readthedocs.io/e

 Please report issues on our [GitHub issues](https://github.com/jbarlow83/OCRmyPDF/issues) page, and follow the issue template for quick response.

-Requirements
------------
+## Requirements

 In addition to the required Python version (3.6+), OCRmyPDF requires external program installations of Ghostscript, Tesseract OCR, QPDF, and Leptonica. OCRmyPDF is pure Python, but uses CFFI to portably generate library bindings. OCRmyPDF works on pretty much everything: Linux, macOS, Windows and FreeBSD.

-Press & Media
-------------
+## Press & Media

 - [Going paperless with OCRmyPDF](https://medium.com/@ikirichenko/going-paperless-with-ocrmypdf-e2f36143f46a)
 - [Converting a scanned document into a compressed searchable PDF with redactions](https://medium.com/@treyharris/converting-a-scanned-document-into-a-compressed-searchable-pdf-with-redactions-63f61c34fe4c)
 - [c't 1-2014, page 59](https://heise.de/-2279695): Detailed presentation of OCRmyPDF v1.0 in the leading German IT magazine c't
 - [heise Open Source, 09/2014: Texterkennung mit OCRmyPDF](https://heise.de/-2356670)
 - [heise Durchsuchbare PDF-Dokumente mit OCRmyPDF erstellen](https://www.heise.de/ratgeber/Durchsuchbare-PDF-Dokumente-mit-OCRmyPDF-erstellen-4607592.html)
+- [Excellent Utilities: OCRmyPDF](https://www.linuxlinks.com/excellent-utilities-ocrmypdf-add-ocr-text-layer-scanned-pdfs/)

-Business enquiries
------------------
+## Business enquiries

 OCRmyPDF would not be the software that it is today without companies and users choosing to provide support for feature development and consulting enquiries. We are happy to discuss all enquiries, whether for extending the existing feature set, or integrating OCRmyPDF into a larger system.

-License
-------
+## License

-The OCRmyPDF software is licensed under the GNU GPLv3. Certain files are covered by other licenses, as noted in their source files.
+The OCRmyPDF software is licensed under the Mozilla Public License 2.0
+(MPL-2.0). This license permits integration of OCRmyPDF with other code,
+included commercial and closed source, but asks you to publish source-level
+modifications you make to OCRmyPDF.

-The license for each test file varies, and is noted in tests/resources/README.rst. The documentation is licensed under Creative Commons Attribution-ShareAlike 4.0 (CC-BY-SA 4.0).
+Some components of OCRmyPDF have other licenses, as noted in those files and the
+``debian/copyright`` file. Most files in ``misc/`` use the MIT license, and the
+documentation and test files are generally licensed under Creative Commons
+ShareAlike 4.0 (CC-BY-SA 4.0).

-OCRmyPDF versions prior to 6.0 were distributed under the MIT License.
-
-Disclaimer
----------
+## Disclaimer

 The software is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -152,16 +152,24 @@ stages:
        strategy:
          matrix:
            Python37:
-              python.version: "3.7"
+              python.version: ""
            Python38:
-              python.version: "3.8"
+              python.version: "python@3.8"
        steps:
-          - task: UsePythonVersion@0
-            inputs:
-              versionSpec: "$(python.version)"
+          # https://github.com/actions/virtual-environments/issues/664
+          # - task: UsePythonVersion@0
+          #   inputs:
+          #     versionSpec: "$(python.version)"
          - bash: |
              brew update
              brew unlink python@2
+              if [ "$(python.version)" != "" ]; then
+                brew upgrade $(python.version)
+              else
+                echo "Using Python `python3 --version`"
+              fi
+            displayName: "Update brew and Python"
+          - bash: |
              brew install \
                exempi \
                ghostscript \
@@ -2,18 +2,58 @@ Format: https://www.debian.org/doc/packaging-manuals/copyright-format/1.0/
 Upstream-Name: OCRmyPDF
 Upstream-Contact: James R. Barlow <barlow.jim@gmail.com>
 Source: https://github.com/jbarlow83/OCRmyPDF
-Files-Excluded: tests/resources/milk.pdf

 Files: *
 Copyright:
- (C) 2013-2017 The OCRmyPDF Authors
- (C) 2013-2016, 2015-2017 2016, 2017, 2017-2018, 2018 James R. Barlow
-License: GPL-3+
+ (C) 2013-2015 Julien Pfefferkorn
+ (C) 2015-2020 James R. Barlow
+ (C) 2019 Martin Wind
+License: MPL-2.0
+
+Files: misc/*
+Copyright:
+ (C) 2020 James R. Barlow
+License: Expat
+
+Files: misc/completion/ocrmypdf.bash
+Copyright:
+ (C) 2019 Frank Pille
+ (C) 2020 Alex Willner
+License: Expat
+
+Files: misc/completion/ocrmypdf.fish
+Copyright:
+ (C) 2020 James R. Barlow
+License: Expat
+
+Files: misc/batch.py
+Copyright:
+ (C) 2016 findingorder: https://github.com/findingorder
+License: Expat
+
+Files: misc/synology.py
+Copyright:
+ (C) github.com/Enantiomerie
+License: Expat
+
+Files: misc/watcher.py
+Copyright:
+ (C) 2019 Ian Alexander: https://github.com/ianalexander
+ (C) 2020 James R. Barlow
+License: Expat
+
+Files: misc/webservice.py
+Copyright: (C) 2019 James R. Barlow
+License: AGPL-3+

 Files: docs tests/resources/*
 Copyright: (C) 2013-2018 James R. Barlow
 License: CC-BY-SA-4.0

+Files: docs/images/bitmap_vs_svg.svg
+Copyright: (C) 2006 Yug
+License: CC-BY-SA-2.5
+
 Files: src/ocrmypdf/hocrtransform.py
 Copyright: (C) 2010 Jonathan Brinley <jonathanbrinley@gmail.com>
 (C) 2013-14 Julien Pfefferkorn
@@ -30,7 +70,7 @@ Copyright: (C) 2014 Armin Ronacher
 (C) 2017 James R. Barlow
 License: BSD-3-clause

-Files: tests/spoof/*
+Files: tests/plugins/*
 Copyright: (C) 2016, 2017, 2016-2018 James R. Barlow
 License: Expat

@@ -79,15 +119,20 @@ Copyright: held by the contributors to the Wikipedia article "Optical character
 (epson.pdf generated from Wikipedia article as of 2016-09-14)
 License: CC-BY-SA-3.0

-Files: tests/resources/typewriter.png tests/resources/2400dpi.pdf tests/resources/3small.pdf
+Files: tests/resources/typewriter.png tests/resources/2400dpi.pdf
 Copyright: (C) 2005 Ellywa
 License: GFDL-1.2+ or CC-BY-SA-1.0 or CC-BY-SA-2.0 or CC-BY-SA-2.5 or CC-BY-SA-3.0
+Comment:
+ Obtained from: https://commons.wikimedia.org/wiki/File:Triumph.typewriter_text_Linzensoep.gif

 Files: tests/resources/overlay.pdf
 Copyright: (C) 2017 Max Anderson
 License: Expat

-Files: tests/resources/baiona*.png tests/resources/3small.pdf
+Files:
+ tests/resources/baiona*.png
+ tests/resources/baiona*.jpg
+ tests/resources/link.pdf
 Copyright: (C) 2014 Euskaldunaa
 License: CC-BY-SA-4.0

@@ -95,6 +140,13 @@ Files: tests/resources/vector.pdf
 Copyright: (C) 2018 Catscratch
 License: Expat

+Files: tests/resources/3small.pdf
+Copyright: (C) 2014 Euskaldunaa
+ (C) 2017 James R. Barlow
+ (C) 2005 Ellywa
+License: CC-BY-SA-4.0 and (GFDL-1.2+ or CC-BY-SA-1.0 or CC-BY-SA-2.0 or CC-BY-SA-2.5 or CC-BY-SA-3.0)
+Comment: concatenation of baiona_gray.png, crom.png and typewriter.png/2400dpi.pdf
+
 Files: src/ocrmypdf/data/sRGB.icc
 Copyright:  Kai-Uwe Behrmann <www.behrmann.name>
            Marti Maria <www.littlecms.com>
@@ -107,6 +159,13 @@ Files: debian/*
 Copyright: (C) 2016 Sean Whitton <spwhitton@spwhitton.name>
 License: GPL-3+

+License: MPL-2.0
+ This Source Code Form is subject to the terms of the Mozilla Public
+ License, v. 2.0.
+ .
+ On Debian systems the full text of the MPL-2.0 can be found in
+ /usr/share/common-licenses/MPL-2.0.
+
 License: GPL-3+
 This program is free software; you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -124,6 +183,669 @@ License: GPL-3+
 On Debian systems, the complete text of the GNU General
 Public License version 3 can be found in "/usr/share/common-licenses/GPL-3".

+License: AGPL-3+
+                     GNU AFFERO GENERAL PUBLIC LICENSE
+                        Version 3, 19 November 2007
+ .
+  Copyright (C) 2007 Free Software Foundation, Inc. <http://fsf.org/>
+  Everyone is permitted to copy and distribute verbatim copies
+  of this license document, but changing it is not allowed.
+ .
+                             Preamble
+ .
+   The GNU Affero General Public License is a free, copyleft license for
+ software and other kinds of works, specifically designed to ensure
+ cooperation with the community in the case of network server software.
+ .
+   The licenses for most software and other practical works are designed
+ to take away your freedom to share and change the works.  By contrast,
+ our General Public Licenses are intended to guarantee your freedom to
+ share and change all versions of a program--to make sure it remains free
+ software for all its users.
+ .
+   When we speak of free software, we are referring to freedom, not
+ price.  Our General Public Licenses are designed to make sure that you
+ have the freedom to distribute copies of free software (and charge for
+ them if you wish), that you receive source code or can get it if you
+ want it, that you can change the software or use pieces of it in new
+ free programs, and that you know you can do these things.
+ .
+   Developers that use our General Public Licenses protect your rights
+ with two steps: (1) assert copyright on the software, and (2) offer
+ you this License which gives you legal permission to copy, distribute
+ and/or modify the software.
+ .
+   A secondary benefit of defending all users' freedom is that
+ improvements made in alternate versions of the program, if they
+ receive widespread use, become available for other developers to
+ incorporate.  Many developers of free software are heartened and
+ encouraged by the resulting cooperation.  However, in the case of
+ software used on network servers, this result may fail to come about.
+ The GNU General Public License permits making a modified version and
+ letting the public access it on a server without ever releasing its
+ source code to the public.
+ .
+   The GNU Affero General Public License is designed specifically to
+ ensure that, in such cases, the modified source code becomes available
+ to the community.  It requires the operator of a network server to
+ provide the source code of the modified version running there to the
+ users of that server.  Therefore, public use of a modified version, on
+ a publicly accessible server, gives the public access to the source
+ code of the modified version.
+ .
+   An older license, called the Affero General Public License and
+ published by Affero, was designed to accomplish similar goals.  This is
+ a different license, not a version of the Affero GPL, but Affero has
+ released a new version of the Affero GPL which permits relicensing under
+ this license.
+ .
+   The precise terms and conditions for copying, distribution and
+ modification follow.
+ .
+                        TERMS AND CONDITIONS
+ .
+   0. Definitions.
+ .
+   "This License" refers to version 3 of the GNU Affero General Public License.
+ .
+   "Copyright" also means copyright-like laws that apply to other kinds of
+ works, such as semiconductor masks.
+ .
+   "The Program" refers to any copyrightable work licensed under this
+ License.  Each licensee is addressed as "you".  "Licensees" and
+ "recipients" may be individuals or organizations.
+ .
+   To "modify" a work means to copy from or adapt all or part of the work
+ in a fashion requiring copyright permission, other than the making of an
+ exact copy.  The resulting work is called a "modified version" of the
+ earlier work or a work "based on" the earlier work.
+ .
+   A "covered work" means either the unmodified Program or a work based
+ on the Program.
+ .
+   To "propagate" a work means to do anything with it that, without
+ permission, would make you directly or secondarily liable for
+ infringement under applicable copyright law, except executing it on a
+ computer or modifying a private copy.  Propagation includes copying,
+ distribution (with or without modification), making available to the
+ public, and in some countries other activities as well.
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+   To "convey" a work means any kind of propagation that enables other
+ parties to make or receive copies.  Mere interaction with a user through
+ a computer network, with no transfer of a copy, is not conveying.
+ .
+   An interactive user interface displays "Appropriate Legal Notices"
+ to the extent that it includes a convenient and prominently visible
+ feature that (1) displays an appropriate copyright notice, and (2)
+ tells the user that there is no warranty for the work (except to the
+ extent that warranties are provided), that licensees may convey the
+ work under this License, and how to view a copy of this License.  If
+ the interface presents a list of user commands or options, such as a
+ menu, a prominent item in the list meets this criterion.
+ .
+   1. Source Code.
+ .
+   The "source code" for a work means the preferred form of the work
+ for making modifications to it.  "Object code" means any non-source
+ form of a work.
+ .
+   A "Standard Interface" means an interface that either is an official
+ standard defined by a recognized standards body, or, in the case of
+ interfaces specified for a particular programming language, one that
+ is widely used among developers working in that language.
+ .
+   The "System Libraries" of an executable work include anything, other
+ than the work as a whole, that (a) is included in the normal form of
+ packaging a Major Component, but which is not part of that Major
+ Component, and (b) serves only to enable use of the work with that
+ Major Component, or to implement a Standard Interface for which an
+ implementation is available to the public in source code form.  A
+ "Major Component", in this context, means a major essential component
+ (kernel, window system, and so on) of the specific operating system
+ (if any) on which the executable work runs, or a compiler used to
+ produce the work, or an object code interpreter used to run it.
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+   The "Corresponding Source" for a work in object code form means all
+ the source code needed to generate, install, and (for an executable
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+ programs which are used unmodified in performing those activities but
+ which are not part of the work.  For example, Corresponding Source
+ includes interface definition files associated with source files for
+ the work, and the source code for shared libraries and dynamically
+ linked subprograms that the work is specifically designed to require,
+ such as by intimate data communication or control flow between those
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+
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 Permission is hereby granted, free of charge, to any person obtaining
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@@ -148,7 +148,8 @@ In addition to tesseract, OCRmyPDF uses the following external binaries:

 -  ``gs`` (Ghostscript)
 -  ``unpaper``
-  ``qpdf``
+-  ``pngquant``
+-  ``jbig2``

 In each case OCRmyPDF will search the ``PATH`` environment variable to
 locate the binaries.
@@ -51,6 +51,18 @@ Forking a child process to call ``ocrmypdf.ocr()`` is suggested. That
 way your application will survive and remain interactive even if
 OCRmyPDF does not.

+Programs that call ``ocrmypdf.ocr()`` should also install a SIGBUS signal
+handler (except on Windows), to raise an exception if access to a memory
+mapped file fails. OCRmyPDF may use memory mapping.
+
+.. warning::
+
+    On Windows, the script that calls ``ocrmypdf.ocr()`` must be protected
+    by an "ifmain" guard (``if __name__ == '__main__'``) or you must use
+    ``ocrmypdf.ocr(...use_threads=True)``. If you do not take at least one
+    of these steps, Windows process semantics will prevent OCRmyPDF from working
+    correctly.
+
 Logging
 -------

@@ -97,8 +109,4 @@ Reference
    :members:
    :undoc-members:

-.. autoclass:: ocrmypdf.ExitCode
-    :members:
-    :undoc-members:
-
 .. autofunction:: ocrmypdf.configure_logging
@@ -0,0 +1,43 @@
+=============
+API Reference
+=============
+
+This page summarizes the rest of the public API. Generally speaking this
+should mainly of interest to plugin developers.
+
+ocrmypdf.exceptions
+===================
+
+.. automodule:: ocrmypdf.exceptions
+    :members:
+    :undoc-members:
+
+ocrmypdf.helpers
+================
+
+.. automodule:: ocrmypdf.helpers
+    :members:
+
+ocrmypdf.hocrtransform
+======================
+
+.. automodule:: ocrmypdf.hocrtransform
+    :members:
+
+ocrmypdf.pdfa
+=============
+
+.. automodule:: ocrmypdf.pdfa
+    :members:
+
+ocrmypdf.quality
+================
+
+.. automodule:: ocrmypdf.quality
+    :members:
+
+ocrmypdf.subprocess
+===================
+
+.. automodule:: ocrmypdf.subprocess
+    :members:
@@ -127,7 +127,7 @@ Users may need to customize the script to meet their requirements.
    "OCR_ON_SUCCESS_DELETE", "This will delete the input file if the exit code is 0 (OK)"
    "OCR_OUTPUT_DIRECTORY_YEAR_MONTH", "This will place files in the output in ``{output}/{year}/{month}/{filename}``"
    "OCR_DESKEW", "Apply deskew to crooked input PDFs"
-    "OCR_JSON_SETTINGS", "A JSON string specifying any other arguments for ``ocrmypdf.ocr``"
+    "OCR_JSON_SETTINGS", "A JSON string specifying any other arguments for ``ocrmypdf.ocr``, e.g. ``'OCR_JSON_SETTINGS={"rotate_pages": true}'``.
    "OCR_POLL_NEW_FILE_SECONDS", "Polling interval"
    "OCR_LOGLEVEL", "Level of log messages to report"

@@ -202,6 +202,13 @@ Alternatives
 -  `Watchman <https://facebook.github.io/watchman/>`__ is a more
   powerful alternative to ``watchmedo``.

+AWS Lambda is not viable
+------------------------
+
+AWS Lambda and its equivalents have low limits on execution time and payload
+size, relative to OCRmyPDF's needs. As of this writing, the request/response
+payload for AWS Lambda was 6 MB, which means many PDFs will not fit.
+
 macOS Automator
 ===============

@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 #
 # ocrmypdf documentation build configuration file, created by
 # sphinx-quickstart on Sun Sep  4 14:29:43 2016.
@@ -21,6 +20,8 @@
 # import sys
 # sys.path.insert(0, os.path.abspath('.'))

+"""isort:skip_file"""
+
 # -- General configuration ------------------------------------------------

 # If your documentation needs a minimal Sphinx version, state it here.
@@ -32,6 +33,8 @@
 # ones.
 extensions = ['sphinx.ext.napoleon']

+napoleon_use_rtype = False
+
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']

@@ -51,7 +54,7 @@ master_doc = 'index'
 # General information about the project.
 project = 'ocrmypdf'
 copyright = (
-    '2019, James R. Barlow. Licensed under Creative Commons Attribution-ShareAlike 4.0.'
+    '2020, James R. Barlow. Licensed under Creative Commons Attribution-ShareAlike 4.0.'
 )
 author = 'James R. Barlow'

@@ -90,6 +93,7 @@ from pkg_resources import get_distribution, DistributionNotFound
 release = get_distribution('ocrmypdf').version
 version = '.'.join(release.split('.')[:2])

+
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
 #
@@ -174,7 +178,7 @@ html_theme_options = {'display_version': False}
 # The name of an image file (relative to this directory) to place at the top
 # of the sidebar.
 #
-# html_logo = None
+# html_logo = "images/logo.svg"  # looks bad

 # The name of an image file (relative to this directory) to use as a favicon of
 # the docs.  This file should be a Windows icon file (.ico) being 16x16 or 32x32
@@ -32,7 +32,8 @@ If you are proposing a change that will require a new Python dependency, we
 prefer dependencies that are already packaged by Debian or Red Hat. This makes
 life much easier for our downstream package maintainers.

-Python dependencies must also be GPLv3 compatible.
+Python dependencies must also be license-compatible. GPLv3 or AGPLv3 are likely
+incompatible with the project's license, but LGPLv3 is compatible.

 New non-Python dependencies
 ===========================
@@ -55,3 +56,12 @@ of that platform.

 Packager maintainers, please ensure that the command line completion scripts in
 ``misc/`` are installed.
+
+Copyright and license
+=====================
+
+For contributions over 10 lines of code, please include your name to list of
+copyright holders for that file. The core program is licensed under MPL-2.0,
+test files and documentation under CC-BY-SA 4.0, and miscellaneous files under
+MIT. Please contribute code only that you wrote and you have the permission to
+contribute or license to us.
@@ -56,7 +56,11 @@ portrait pages.
    ocrmypdf --rotate-pages myfile.pdf myfile.pdf

 You can increase (decrease) the parameter ``--rotate-pages-threshold``
-to make page rotation more (less) aggressive.
+to make page rotation more (less) aggressive. The threshold number is the ratio
+of how confidence the OCR engine is that the document image should be changed,
+compared to kept the same. A value of ``15.0`` is the default, and is fairly
+conservative. A value of ``2.0`` will produce more rotations, and more false
+positives.

 If the page is "just a little off horizontal", like a crooked picture,
 then you want ``--deskew``. ``--rotate-pages`` is for when the cardinal
@@ -90,10 +90,8 @@ Docker volume:

 .. code-block:: bash

-   docker run --rm -v $(pwd):/data ocrmypdf /data/input.pdf /data/output.pdf
-
-(However, when done this way, ``output.pdf`` may be owned by the root
-user.)
+   alias docker_ocrmypdf='docker run --rm  -i --user "$(id -u):$(id -g)" --workdir /data -v "$PWD:/data" ocrmypdf'
+   docker_ocrmypdf /data/input.pdf /data/output.pdf

 .. _docker-lang-packs:

@@ -165,8 +163,7 @@ complete. This may entail setting a long timeout; this interface is more
 useful for internal HTTP API calls.

 Unlike the rest of OCRmyPDF, this web service is licensed under the
-Affero GPLv3 (AGPLv3) since Ghostscript, a dependency of OCRmyPDF, is
-also licensed in this way.
+Affero GPLv3 (AGPLv3) since Ghostscript is also licensed in this way.

 In addition to the above, please read our
 :ref:`general remarks on using OCRmyPDF as a service <ocr-service>`.
@@ -22,14 +22,20 @@ As the error message suggests, your options are:
 -  ``ocrmypdf --skip-text`` to skip OCR and other processing on any
   pages that contain text. Text pages will be copied into the output
   PDF without modification.
+-  ``ocrmypdf --redo-ocr`` to scan the file for any existing OCR
+   (non-printing text), remove it, and do OCR again. This is one way
+   to take advantage of improvements in OCR accuracy. Printable vector
+   text is excluded from OCR, so this can be used on files that contain
+   a mix of digital and scanned files.
+

 Input file 'filename' is not a valid PDF
 ========================================

-OCRmyPDF passes files through qpdf, a program that fixes errors in PDFs,
-before it tries to work on them. In most cases this happens because the
-PDF is corrupt and truncated (incomplete file copying) and not much can
-be done.
+OCRmyPDF checks files with pikepdf, a library that in turn uses libqpdf to fixes
+errors in PDFs, before it tries to work on them. In most cases this happens
+because the PDF is corrupt and truncated (incomplete file copying) and not much
+can be done.

 You can try rewriting the file with Ghostscript:

@@ -26,7 +26,8 @@ image processing and OCR to existing PDFs.
   docker
   advanced
   batch
-   security
+   performance
+   pdfsecurity
   errors

 .. toctree::
@@ -34,6 +35,8 @@ image processing and OCR to existing PDFs.
   :maxdepth: 2

   api
+   plugins
+   apiref
   contributing

 Indices and tables
@@ -8,20 +8,26 @@ Installing OCRmyPDF
 |latest|

 The easiest way to install OCRmyPDF is to follow the steps for your operating
-system/platform, although sometimes this version may be out of date. This
-installation guide provides information allowing you to compare the current
-version to the one provided by your platform.
+system/platform. This version may be out of date, however.

-If you want to use the latest version of OCRmyPDF and all of its optional
-dependencies, the easiest way to get that is install the Homebrew package. Homebrew
-is best known as a macOS package manger, but also works for
-`Linux and Windows Subsystem for Linux <https://docs.brew.sh/Homebrew-on-Linux>`__.
-After Homebrew is installed, simply run ``brew install ocrmypdf``.
+These platforms have one-liner installs:

-You can also use the more detailed procedures here to manually install OCRmyPDF
-from source or with the ``pip`` package manager for binary wheels. The reason
-for these varied steps is that OCRmyPDF requires third-party executables that are
-not part of Python.
+-----------------------------+-------------------------------+
+| Debian, Ubuntu              | ``apt install ocrmypdf``      |
+-----------------------------+-------------------------------+
+| Windows Subsystem for Linux | ``apt install ocrmypdf``      |
+-----------------------------+-------------------------------+
+| Fedora                      | ``dnf install ocrmypdf``      |
+-----------------------------+-------------------------------+
+| macOS                       | ``brew install ocrmypdf``     |
+-----------------------------+-------------------------------+
+| LinuxBrew                   | ``brew install ocrmypdf``     |
+-----------------------------+-------------------------------+
+| FreeBSD                     | ``pkg install py37-ocrmypdf`` |
+-----------------------------+-------------------------------+
+
+More detailed procedures are outlined below. If you want to do a manual
+install, or install a more recent version than your platform provides, read on.

 .. contents:: Platform-specific steps
    :depth: 2
@@ -45,14 +51,8 @@ Debian and Ubuntu 18.04 or newer
 .. |ubu-1804| image:: https://repology.org/badge/version-for-repo/ubuntu_18_04/ocrmypdf.svg
    :alt: Ubuntu 18.04 LTS

-.. |ubu-1810| image:: https://repology.org/badge/version-for-repo/ubuntu_18_10/ocrmypdf.svg
-    :alt: Ubuntu 18.10
-
-.. |ubu-1904| image:: https://repology.org/badge/version-for-repo/ubuntu_19_04/ocrmypdf.svg
-    :alt: Ubuntu 19.04
-
-.. |ubu-1910| image:: https://repology.org/badge/version-for-repo/ubuntu_19_10/ocrmypdf.svg
-    :alt: Ubuntu 19.10
+.. |ubu-2004| image:: https://repology.org/badge/version-for-repo/ubuntu_20_04/ocrmypdf.svg
+    :alt: Ubuntu 20.04 LTS

 +-----------------------------------------------+
 | **OCRmyPDF versions in Debian & Ubuntu**      |
@@ -61,10 +61,10 @@ Debian and Ubuntu 18.04 or newer
 +-----------------------------------------------+
 | |deb-stable| |deb-testing| |deb-unstable|     |
 +-----------------------------------------------+
-| |ubu-1804| |ubu-1810| |ubu-1904| |ubu-1910|   |
+| |ubu-1804| |ubu-2004|                         |
 +-----------------------------------------------+

-Users of Debian 9 ("stretch") or later or Ubuntu 18.04 or later, including users
+Users of Debian 9 ("stretch") or later, or Ubuntu 18.04 or later, including users
 of Windows Subsystem for Linux, may simply

 .. code-block:: bash
@@ -93,11 +93,11 @@ For full details on version availability for your platform, check the
 Fedora 29 or newer
 ------------------

-.. |fedora-29| image:: https://repology.org/badge/version-for-repo/fedora_29/ocrmypdf.svg
-    :alt: Fedora 29
+.. |fedora-31| image:: https://repology.org/badge/version-for-repo/fedora_31/ocrmypdf.svg
+    :alt: Fedora 31

-.. |fedora-30| image:: https://repology.org/badge/version-for-repo/fedora_30/ocrmypdf.svg
-    :alt: Fedora 30
+.. |fedora-32| image:: https://repology.org/badge/version-for-repo/fedora_32/ocrmypdf.svg
+    :alt: Fedora 32

 .. |fedora-rawhide| image:: https://repology.org/badge/version-for-repo/fedora_rawhide/ocrmypdf.svg
    :alt: Fedore Rawhide
@@ -107,7 +107,7 @@ Fedora 29 or newer
 +-----------------------------------------------+
 | |latest|                                      |
 +-----------------------------------------------+
-| |fedora-29| |fedora-30| |fedora-rawhide|      |
+| |fedora-31| |fedora-32| |fedora-rawhide|      |
 +-----------------------------------------------+

 Users of Fedora 29 or later may simply
@@ -133,15 +133,50 @@ from sources <#installing-head-revision-from-sources>`__.

 .. _ubuntu-lts-latest:

-Installing the latest version on Ubuntu 18.04 LTS
+Installing the latest version on Ubuntu 20.04 LTS
 -------------------------------------------------

-Ubuntu 18.04 includes ocrmypdf 6.1.2 - you can install that with ``apt``, but
-it is quite old now. To install a more recent version, first install several
-system dependencies:
+Ubuntu 20.04 includes ocrmypdf 9.6.0 - you can install that with ``apt``. To
+install a more recent version, uninstall the system-provided version of
+ocrmypdf, and install the following dependencies:

 .. code-block:: bash

+    sudo apt-get -y remove ocrmypdf  # remove system ocrmypdf, if installed
+    sudo apt-get -y update
+    sudo apt-get -y install \
+        ghostscript \
+        icc-profiles-free \
+        liblept5 \
+        libxml2 \
+        pngquant \
+        python3-pip \
+        tesseract-ocr \
+        zlib1g
+
+To install ocrmypdf for the system:
+
+.. code-block:: bash
+
+    sudo pip3 install ocrmypdf
+
+To install for the current user only:
+
+.. code-block:: bash
+
+    export PATH=$HOME/.local/bin:$PATH
+    pip3 install --user ocrmypdf
+
+Ubuntu 18.04 LTS
+----------------
+
+Ubuntu 18.04 includes ocrmypdf 6.1.2 - you can install that with ``apt``, but
+it is quite old now. To install a more recent version, uninstall the old version
+of ocrmypdf, and install the following dependencies:
+
+.. code-block:: bash
+
+    sudo apt-get -y remove ocrmypdf
    sudo apt-get -y update
    sudo apt-get -y install \
        ghostscript \
@@ -236,68 +271,6 @@ environment variable contains ``$HOME/.local/bin``.

 To add JBIG2 encoding, see :ref:`jbig2`.

-Ubuntu 14.04 LTS
----------------
-
-Installing on Ubuntu 14.04 LTS (trusty) is more difficult than some
-other options, because of its age. Several backports are required. For
-explanations of some steps of this procedure, see the similar steps for
-Ubuntu 16.04.
-
-Install system dependencies:
-
-.. code-block:: bash
-
-    sudo apt-get update
-    sudo apt-get install \
-        software-properties-common python-software-properties \
-        zlib1g-dev \
-        libexempi3 \
-        libjpeg-dev \
-        libffi-dev \
-        pngquant \
-        qpdf
-
-We will need backports of Ghostscript 9.16, libav-11 (for unpaper 6.1),
-Tesseract 4.00 (alpha), and Python 3.6. This will replace Ghostscript
-and Tesseract 3.x on your system. Python 3.6 will be installed alongside
-the system Python 3.4.
-
-If you prefer to not modify your system in this matter, consider using a
-Docker container.
-
-.. code-block:: bash
-
-    sudo add-apt-repository ppa:vshn/ghostscript -y
-    sudo add-apt-repository ppa:heyarje/libav-11 -y
-    sudo add-apt-repository ppa:alex-p/tesseract-ocr -y
-    sudo add-apt-repository ppa:jonathonf/python-3.6 -y
-
-    sudo apt-get update
-
-    sudo apt-get install \
-        python3.6-dev \
-        ghostscript \
-        tesseract-ocr \
-        tesseract-ocr-eng \
-        libavformat56 libavcodec56 libavutil54 \
-        wget
-
-Now we need to install ``pip`` and let it install ocrmypdf:
-
-.. code-block:: bash
-
-    curl https://bootstrap.pypa.io/ez_setup.py -o - | python3.6 && python3.6 -m easy_install pip
-    pip3.6 install ocrmypdf
-
-The optional dependency ``unpaper`` is only available at 0.4.2 in Ubuntu 14.04,
-and no backports are available. Previously the author maintained a backported
-.deb package for unpaper 6.1, but since Ubuntu 14.04 is now end of life, this is
-not supported. As such, ``unpaper`` is not available on Ubuntu 14.04 or must by
-compiled by hand.
-
-To add JBIG2 encoding, see :ref:`jbig2`.
-
 Arch Linux (AUR)
 ----------------

@@ -326,20 +299,7 @@ standard tooling needed to build packages, such as a compiler and binary tools.

   sudo pacman -S base-devel

-The OCRmyPDF package depends on `the python-pdfminer.six AUR package
-<https://aur.archlinux.org/packages/python-pdfminer.six/>`__.  Dependencies on
-AUR packages are not automatically resolved, so this package must be manually
-installed first.
-
-.. code-block:: bash
-
-   curl -O https://aur.archlinux.org/cgit/aur.git/snapshot/python-pdfminer.six.tar.gz
-   tar xvzf python-pdfminer.six.tar.gz
-   cd python-pdfminer.six
-   makepkg -sri
-
-With that complete you can then repeat the same series of steps for the
-OCRmyPDF package.
+Now you are ready to install the OCRmyPDF package.

 .. code-block:: bash

@@ -373,11 +333,10 @@ page.
    fine without it but will produce larger output files. The encoder is
    available from `the jbig2enc-git AUR package
    <https://aur.archlinux.org/packages/jbig2enc-git/>`__ and may be installed
-    using the same series of steps as for the installation of the pdfminer.six
-    and OCRmyPDF AUR packages. Alternatively, it may be built manually from
-    source following the instructions in `Installing the JBIG2 encoder
-    <jbig2>`__.  If JBIG2 is installed, OCRmyPDF 7.0.0 and later will
-    automatically detect it.
+    using the same series of steps as for the installation OCRmyPDF AUR
+    package. Alternatively, it may be built manually from source following the
+    instructions in `Installing the JBIG2 encoder <jbig2>`__.  If JBIG2 is
+    installed, OCRmyPDF 7.0.0 and later will automatically detect it.

 Alpine Linux
 ------------
@@ -392,6 +351,43 @@ To install OCRmyPDF for Alpine Linux:

    apk add ocrmypdf

+Mageia 7
+--------
+
+Install the following dependencies:
+
+.. code-block:: bash
+
+    # As root user
+    urpmi.update -a
+    urpmi \
+        ghostscript \
+        icc-profiles-openicc \
+        jbig2dec \
+        lib64leptonica5 \
+        pngquant \
+        python3-pip \
+        python3-cffi \
+        python3-distutils-extra \
+        python3-pkg-resources \
+        python3-reportlab \
+        qpdf \
+        tesseract \
+        tesseract-osd \
+        tesseract-eng \
+        tesseract-fra
+
+To install ocrmypdf for the system:
+
+    # As root user
+    pip3 install ocrmypdf
+    ldconfig
+
+Or, to install for the current user only:
+
+    export PATH=$HOME/.local/bin:$PATH
+    pip3 install --user ocrmypdf
+
 Other Linux packages
 --------------------

@@ -442,7 +438,10 @@ languages you can optionally install them all:
 Manual installation on macOS
 ----------------------------

-These instructions probably work on all macOS supported by Homebrew.
+These instructions probably work on all macOS supported by Homebrew, and are
+for installing a more current version of OCRmyPDF than is available from
+Homebrew. Note that the Homebrew versions usually track the release versions
+fairly closely.

 If it's not already present, `install Homebrew <http://brew.sh/>`__.

@@ -453,14 +452,8 @@ Update Homebrew:
    brew update

 Install or upgrade the required Homebrew packages, if any are missing.
-To do this, download the ``Brewfile`` that lists all of the dependencies
-to the current directory, and run ``brew bundle`` to process them
-(installing or upgrading as needed). ``Brewfile`` is a plain text file.
-
-.. code-block:: bash
-
-    wget https://github.com/jbarlow83/OCRmyPDF/raw/master/.travis/Brewfile
-    brew bundle
+To do this, use ``brew edit ocrmypdf`` to obtain a recent list of Homebrew
+dependencies. You could also check the ``azure-pipelines.yml``.

 This will include the English, French, German and Spanish language
 packs. If you need other languages you can optionally install them all:
@@ -495,40 +488,15 @@ The command line program should now be available:

    ocrmypdf --help

-Installing on FreeBSD
-=====================
-
-.. image:: https://repology.org/badge/version-for-repo/freebsd/python:ocrmypdf.svg
-    :alt: FreeBSD
-    :target: https://repology.org/project/python:ocrmypdf/versions
-
-FreeBSD 11.3, 12.0, 12.1-RELEASE and 13.0-CURRENT are supported. Other
-versions likely work but have not been tested.
-
-.. code-block:: bash
-
-    pkg install py37-ocrmypdf
-
-To install a more recent version, you could attempt to first install the system
-version with ``pkg``, then use ``pip install --user ocrmypdf``.
-
-Installing the Docker image
-===========================
-
-For some users, installing the Docker image will be easier than
-installing all of OCRmyPDF's dependencies.
-
-See `OCRmyPDF Docker Image <docker>`__ for more information.
-
 Installing on Windows
 =====================

-.. warning::
+Native Windows
+--------------

-    Native Windows support is new. Consider it "beta" software. Some
-    functionality is missing or may be more difficult to enable. If you need a
-    production-ready solution, use Windows Subsystem for Linux or a Docker
-    image.
+.. note::
+
+    It is easier to install OCRmyPDF on Windows Subsystem for Linux.

 .. note::

@@ -536,7 +504,7 @@ Installing on Windows

 You must install the following for Windows:

-* Python 3.7 (64-bit)
+* Python 3.7 (64-bit) or later
 * Tesseract 4.0 or later
 * Ghostscript 9.50 or later

@@ -565,8 +533,8 @@ You may then use pip to install ocrmypdf:

 * ``pip install ocrmypdf``

-Installing on Windows Subsystem for Linux
-=========================================
+Windows Subsystem for Linux
+---------------------------

 #. Install Ubuntu 18.04 for Windows Subsystem for Linux, if not already installed.
 #. Follow the procedure to install :ref:`OCRmyPDF on Ubuntu 18.04 <ubuntu-lts-latest>`.
@@ -585,12 +553,84 @@ Then confirm that the expected version from PyPI (|latest|) is installed:
 You can then run OCRmyPDF in the Windows command prompt or Powershell, prefixing
 ``wsl``, and call it from Windows programs or batch files.

+Cygwin64
+--------
+
+First install the the following prerequisite Cygwin packages using ``setup-x86_64.exe``::
+
+    python36 (or later)
+    python3?-devel
+    python3?-pip
+    python3?-lxml
+    python3?-imaging
+
+       (where 3? means match the version of python3 you installed)
+
+    gcc-g++
+    ghostscript (<=9.50 or >=9.52-2 see note below)
+    libexempi3
+    libexempi-devel
+    libffi6
+    libffi-devel
+    pngquant
+    qpdf
+    libqpdf-devel
+    tesseract-ocr
+    tesseract-ocr-devel
+
+.. note::
+
+    The Cygwin package for Ghostscript in versions 9.52 and
+    9.52-1 contained a bug that caused an exception to occur when
+    ocrmypdf invoked gs.  Make sure you have either 9.50 (or earlier)
+    or 9.52-2 (or later).
+
+Then open a Cygwin terminal (i.e. ``mintty``), run the following commands. Note
+that if you are using the version of ``pip`` that was installed with the Cygwin
+Python package, the command name will be ``pip3``.  If you have since updated
+``pip`` (with, for instance ``pip3 install --upgrade pip``) the the command is
+likely just ``pip`` instead of ``pip3``:
+
+.. code-block:: bash
+
+    pip3 install wheel
+    pip3 install ocrmypdf
+
+The optional dependency "unpaper" that is currently not available under Cygwin.
+Without it, certain options such as ``--clean`` will produce an error message.
+However, the OCR-to-text-layer functionality is available.
+
 Docker
-^^^^^^
+------

 You can also :ref:`Install the Docker <docker-install>` container on Windows. Ensure that
 your command prompt can run the docker "hello world" container.

+Installing on FreeBSD
+=====================
+
+.. image:: https://repology.org/badge/version-for-repo/freebsd/python:ocrmypdf.svg
+    :alt: FreeBSD
+    :target: https://repology.org/project/python:ocrmypdf/versions
+
+FreeBSD 11.3, 12.0, 12.1-RELEASE and 13.0-CURRENT are supported. Other
+versions likely work but have not been tested.
+
+.. code-block:: bash
+
+    pkg install py37-ocrmypdf
+
+To install a more recent version, you could attempt to first install the system
+version with ``pkg``, then use ``pip install --user ocrmypdf``.
+
+Installing the Docker image
+===========================
+
+For some users, installing the Docker image will be easier than
+installing all of OCRmyPDF's dependencies.
+
+See `OCRmyPDF Docker Image <docker>`__ for more information.
+
 Installing with Python pip
 ==========================

@@ -625,6 +665,13 @@ instead use this for a system wide installation:

    pip3 install ocrmypdf

+.. note::
+
+    AArch64 (ARM64) users: this process will be difficult because most
+    Python packages are not available as binary wheels for your platform.
+    You're probably better off using a platform install on Debian, Ubuntu,
+    or Fedora.
+
 Requirements for pip and HEAD install
 -------------------------------------

@@ -186,6 +186,11 @@ Ghostscript also imposes some limitations:
 -  Ghostscript's PDF/A conversion removes any XMP metadata that is not
   one of the standard XMP metadata namespaces for PDFs. In particular,
   PRISM Metdata is removed.
+-  Ghostscript's PDF/A conversion seems to remove or deactivate
+   hyperlinks and other active content.
+
+You can use ``--output-type pdf`` to disable PDF/A conversion and produce
+a standard, non-archival PDF.

 Regarding OCRmyPDF itself:

@@ -64,11 +64,11 @@ malicious user could upload a chosen PDF. In particular, it is not
 necessarily secure against PDF malware or PDFs that cause denial of
 service. OCRmyPDF relies on Ghostscript, and therefore, if deployed
 online one should be prepared to comply with Ghostscript's Affero GPL
-license, OCRmyPDF's GPL license, and any other licenses.
+license, and any other licenses.

 Setting aside these concerns, a side effect of OCRmyPDF is it may
 incidentally sanitize PDFs that contain certain types of malware. It
-runs ``qpdf`` to repair the PDF, which could correct malformed PDF
+repairs the PDF with pikepdf/libqpdf, which could correct malformed PDF
 structures that are part of an attack. When PDF/A output is selected
 (the default), the input PDF is partially reconstructed by Ghostscript.
 When ``--force-ocr`` is used, all pages are rasterized and reconverted
@@ -144,10 +144,9 @@ set, the document cannot be viewed without the password.
 Either way, OCRmyPDF does not remove passwords from PDFs and exits with
 an error on encountering them.

-``qpdf``, one of OCRmyPDF's dependencies, can remove passwords. If the
-owner and user password are set, a password is required for ``qpdf``. If
-only the owner password is set, then the password can be stripped, even
-if one does not have the owner password.
+``qpdf`` can remove passwords. If the owner and user password are set, a
+password is required for ``qpdf``. If only the owner password is set, then the
+password can be stripped, even if one does not have the owner password.

 After OCR is applied, password protection is not permitted on PDF/A
 documents but the file can be converted to regular PDF.
@@ -0,0 +1,22 @@
+===========
+Performance
+===========
+
+Some users have noticed that current versions of OCRmyPDF do not run as quickly
+as some older versions (specifically 6.x and older). This is because OCRmyPDF
+added image optimization as a postprocessing step, and it is enabled by default.
+
+Speed
+=====
+
+If running OCRmyPDF quickly is your main goal, you can use settings such as:
+
+* ``--optimize 0`` to disable file size optimization
+* ``--output-type pdf`` to disable PDF/A generation
+* ``--fast-web-view 0`` to disable fast web view optimization
+* ``--skip-big`` to skip large images, if some pages have large images
+
+You can also avoid:
+
+* ``--force-ocr``
+* Image preprocessing
@@ -2,23 +2,164 @@
 Plugins
 =======

-You can use plugins to customize the behavior of OCRmyPDF at certain
-points of interest.
+    The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL
+    NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED",  "MAY", and
+    "OPTIONAL" in this document are to be interpreted as described in
+    RFC 2119.

-Currently, it is possible to: - override the decision for whether or not
-to perform OCR on a particular file - modify the image is about to be
-sent for OCR
+You can use plugins to customize the behavior of OCRmyPDF at certain points of
+interest.

-How plugins are imported
-========================
+Currently, it is possible to:

-Plugins are imported on demand, by the OCRmyPDF worker process that
-needs to use them. As such, plugins cannot share state with each other,
-and will be imported many times, once for each worker process.
+- add new command line arguments
+- override the decision for whether or not to perform OCR on a particular file
+- modify the image is about to be sent for OCR
+- modify the page image before it is converted to PDF
+- replace the Tesseract OCR with another OCR engine that has similar behavior
+- replace Ghostscript with another PDF to image converter (rasterizer) or
+  PDF/A generator

-Plugins currently cannot override the same hook.
+OCRmyPDF plugins are based on the Python ``pluggy`` package and conform to its
+conventions. Note that: plugins installed with as setuptools entrypoints are
+not checked currently, because OCRmyPDF assumes you may not want to enable
+plugins for all files.

-How plugins are invoked
-=======================
+Script plugins
+==============

-Plugins may be called from the command line:
+Script plugins may be called from the command line, by specifying the name of a file.
+Script plugins may be convenient for informal or "one-off" plugins, when a certain
+batch of files needs a special processing step for example.
+
+.. code-block:: bash
+
+    ocrmypdf --plugin ocrmypdf_example_plugin.py input.pdf output.pdf
+
+Multiple plugins may be installed by issuing the ``--plugin`` argument multiple times.
+
+Packaged plugins
+================
+
+Installed plugins may be installed into the same virtual environment as OCRmyPDF
+is installed into. They may be invoked using Python standard module naming.
+If you are intending to distribute a plugin, please package it.
+
+.. code-block:: bash
+
+    ocrmypdf --plugin ocrmypdf_fancypants.pockets.contents input.pdf output.pdf
+
+OCRmyPDF does not automatically import plugins, because the assumption is that
+plugins affect different files differently and you may not want them activated
+all the time. The command line or ``ocrmypdf.ocr(plugin='...')`` must call
+for them.
+
+Third parties that wish to distribute packages for ocrmypdf should package them
+as packaged plugins, and these modules should begin with the name ``ocrmypdf_``
+similar to ``pytest`` packages such as ``pytest-cov`` (the package) and
+``pytest_cov`` (the module).
+
+.. note::
+
+    We strongly recommend plugin authors name their plugins with the prefix
+    ``ocrmypdf-`` (for the package name on PyPI) and ``ocrmypdf_`` (for the
+    module), just like pytest plugins.
+
+Plugin requirements
+===================
+
+OCRmyPDF generally uses multiple worker processes. When a new worker is started,
+Python will import all plugins again, including all plugins that were imported earlier.
+This means that the global state of a plugin in one worker will not be shared with
+other workers. As such, plugin hook implementations should be stateless, relying
+only on their inputs. Hook implementations may use their input parameters to
+to obtain a reference to shared state prepared by another hook implementation.
+Plugins must expect that other instances of the plugin will be running
+simultaneously.
+
+The ``context`` object that is passed to many hooks can be used to share information
+about a file being worked on. Plugins must write private, plugin-specific data to
+a subfolder named ``{options.work_folder}/ocrmypdf-plugin-name``. Plugins MAY
+read and write files in ``options.work_folder``, but should be aware that their
+semantics are subject to change.
+
+OCRmyPDF will delete ``options.work_folder`` when it has finished OCRing
+a file, unless invoked with ``--keep-temporary-files``.
+
+The documentation for some plugin hooks contain a detailed description of the
+execution context in which they will be called.
+
+Plugins should be prepared to work whether executed in worker threads or worker
+processes. Generally, OCRmyPDF uses processes, but has a semi-hidden threaded
+argument that simplifies debugging.
+
+
+Plugin hooks
+============
+
+A plugin may provide the following hooks. Hooks must be decorated with
+``ocrmypdf.hookimpl``, for example:
+
+.. code-block:: python
+
+    from ocrmpydf import hookimpl
+
+    @hookimpl
+    def add_options(parser):
+        pass
+
+The following is a complete list of hooks that are available, and when
+they are called.
+
+.. _firstresult:
+
+**Note on firstresult hooks**
+
+If multiple plugins install implementations for this hook, they will be called in
+the reverse of the order in which they are installed (i.e., last plugin wins).
+When each hook implementation is called in order, the first implementation that
+returns a value other than ``None`` will "win" and prevent execution of all other
+hooks. As such, you cannot "chain" a series of plugin filters together in this
+way. Instead, a single hook implementation should be responsible for any such
+chaining operations.
+
+Custom command line arguments
+-----------------------------
+
+.. autofunction:: ocrmypdf.pluginspec.add_options
+
+.. autofunction:: ocrmypdf.pluginspec.check_options
+
+Applying special behavior before processing
+-------------------------------------------
+
+.. autofunction:: ocrmypdf.pluginspec.validate
+
+PDF page to image
+-----------------
+
+.. autofunction:: ocrmypdf.pluginspec.rasterize_pdf_page
+
+Modifying intermediate images
+-----------------------------
+
+.. autofunction:: ocrmypdf.pluginspec.filter_ocr_image
+
+.. autofunction:: ocrmypdf.pluginspec.filter_page_image
+
+OCR engine
+----------
+
+.. autofunction:: ocrmypdf.pluginspec.get_ocr_engine
+
+.. autoclass:: ocrmypdf.pluginspec.OcrEngine
+    :members:
+
+    .. automethod:: __str__
+
+.. autoclass:: ocrmypdf.pluginspec.OrientationConfidence
+
+PDF/A production
+----------------
+
+.. autofunction:: ocrmypdf.pluginspec.generate_pdfa
@@ -5,14 +5,189 @@ Release notes
 OCRmyPDF uses `semantic versioning <http://semver.org/>`__ for its
 command line interface and its public API.

-The ``ocrmypdf`` package may now be imported. The public API may be
-useful in scripts that launch OCRmyPDF processes or that wish to use
-some of its features for working with PDFs.
+OCRmyPDF's output messages are not considered part of the stable interface -
+that is, output messages may be improved at any release level, so parsing them
+may be unreliable. Use the API to depend on precise behavior.

-Note that it is licensed under GPLv3, so scripts that
-``import ocrmypdf`` and are released publicly should probably also be
-licensed under GPLv3.
+The public API may be useful in scripts that launch OCRmyPDF processes or that
+wish to use some of its features for working with PDFs.

+v11.0.0
+=======
+
+-  Project license changed to Mozilla Public License 2.0. Some miscellaneous
+   code is now under MIT license and non-code content/media remains under
+   CC-BY-SA 4.0. License changed with approval of all people who were found
+   to have contributed to GPLv3 licensed sections of the project. (#600)
+-  Because the license changed, this is being treated as a major version number
+   change; however, there are no known breaking changes in functional behavior
+   or API compared to v10.x.
+
+v10.3.3
+=======
+
+-  Fixed a "KeyError: 'dpi'" error message when using ``--threshold`` on an image.
+   (#607)
+
+v10.3.2
+=======
+
+-  Fixed a case where we reported "no reason" for a file size increase, when we
+   could determine the reason.
+-  Enabled support for pdfminer.six 20200726.
+
+v10.3.1
+=======
+
+-  Fixed a number of test suite failures with pdfminer.six older than veresion 20200402.
+-  Enabled support for pdfminer.six 20200720.
+
+v10.3.0
+=======
+
+-  Fixed an issue where we would consider images that were already JBIG2-encoded
+   for optimization, potentially producing a less optimized image than the original.
+   We do not believe this issue would ever cause an image to loss fidelity.
+-  Where available, pikepdf memory mapping is now used. This improves performance.
+-  When Leptonica 1.79+ is installed, use its new error handling API to avoid
+   a "messy" redirection of stderr which was necessary to capture its error
+   messages.
+-  For older versions of Leptonica, added a new thread level lock. This fixes a
+   possible race condition in handling error conditions in Leptonica (although
+   there is no evidence it ever caused issues in practice).
+-  Documentation improvements and more type hinting.
+
+v10.2.1
+=======
+
+-  Disabled calculation of text box order with pdfminer. We never needed this result
+   and it is expensive to calculate on files with complex pre-existing text.
+-  Fixed plugin manager to accept ``Path(plugin)`` as a path to a plugin.
+-  Fixed some typing errors.
+-  Documentation improvements.
+
+v10.2.0
+=======
+
+-  Update Docker image to use Ubuntu 20.04.
+-  Fixed issue PDF/A acquires title "Untitled" after conversion. (#582)
+-  Fixed a problem where, when using ``--pdf-renderer hocr``, some text would
+   be missing from the output when using a more recent version of Tesseract.
+   Tesseract began adding more detailed markup about the semantics of text
+   that our HOCR transform did not recognize, so it ignored them. This option is
+   not the default. If necessary ``--redo-ocr`` also redoing OCR to fix such issues.
+-  Fixed an error in Python 3.9 beta, due to removal of deprecated
+   ``Element.getchildren()``. (#584)
+-  Implemented support using the API with ``BytesIO`` and other file stream objects.
+   (#545)
+
+v10.1.1
+=======
+
+-  Fixed ``OMP_THREAD_LIMIT`` set to invalid value error messages on some input
+   files. (The error was harmless, apart from less than optimal performance in
+   some cases.)
+
+v10.1.0
+=======
+
+-  Previously, we ``--clean-final`` would cause an unpaper-cleaned page image to
+   be produced twice, which was necessary in some cases but not in general. We
+   now take this optimization opportunity and reuse the image if possible.
+-  We now provide PNG files as input to unpaper, since it accepts them, instead
+   of generating PPM files which can be very large. This can improve performance
+   and temporary disk usage.
+-  Documentation updated for plugins.
+
+v10.0.1
+=======
+
+-  Fixed regression when ``-l lang1+lang2`` is used from command line.
+
+v10.0.0
+=======
+
+**Breaking changes**
+
+-  Support for pdfminer.six version 20181108 has been dropped, along with a
+   monkeypatch that made this version work.
+-  Output messages are now displayed in color (when supported by the terminal)
+   and prefixes describing the severity of the message are removed. As such
+   programs that parse OCRmyPDF's log message will need to be revised. (Please
+   consider using OCRmyPDF as a library instead.)
+-  The minimum version for certain dependencies has increased.
+-  Many API changes; see developer changes.
+-  The Python libraries pluggy and coloredlogs are now required.
+
+**New features and improvements**
+
+-  PDF page scanning is now parallelized across CPUs, speeding up this phase
+   dramatically for files with a high page counts.
+-  PDF page scanning is optimized, addressing some performance regressions.
+-  PDF page scanning is no longer run on pages that are not selected when the
+   ``--pages`` argument is used.
+-  PDF page scanning is now independent of Ghostscript, ending our past reliance
+   on this occasionally unstable feature in Ghostscript.
+-  A plugin architecture has been added, currently allowing one to more easily
+   use a different OCR engine or PDF renderer from Tesseract and Ghostscript,
+   respectively. A plugin can also override some decisions, such changing
+   the OCR settings after initial scanning.
+-  Colored log messages.
+
+**Developer changes**
+
+-  The test spoofing mechanism, used to test correct handling of failures in
+   Tesseract and Ghostscript, has been removed in favor of using plugins for
+   testing. The spoofing mechanism was fairly complex and required many special
+   hacks for Windows.
+-  Code describing the resolution in DPI of images was refactored into a
+   ``ocrmypdf.helpers.Resolution`` class.
+-  The module ``ocrmypdf._exec`` is now private to OCRmyPDF.
+-  The ``ocrmypdf.hocrtransform`` module has been updated to follow PEP8 naming
+   conventions.
+-  Ghostscript is no longer used for finding the location of text in PDFs, and
+   APIs related to this feature have been removed.
+-  Lots of internal reorganization to support plugins.
+
+v9.8.2
+======
+
+-  Fixed an issue where OCRmyPDF would ignore text inside Form XObject when
+   making certain decisions about whether a document already had text.
+-  Fixed file size increase warning to take overhead of small files into account.
+-  Added instructions for installing on Cygwin.
+
+v9.8.1
+======
+
+-  Fixed an issue where unexpected files in the ``%PROGRAMFILES%\gs`` directory
+   (Windows) caused an exception.
+-  Mark pdfminer.six 20200517 as supported.
+-  If jbig2enc is missing and optimization is requested, a warning is issued
+   instead of an error, which was the intended behavior.
+-  Documentation updates.
+
+v9.8.0
+======
+
+-  Fixed issue where only the first PNG (FlateDecode) image in a file would be
+   considered for optimization. File sizes should be improved from here on.
+-  Fixed a startup crash when the chosen language was Japanese (#543).
+-  Added options to configure polling and log level to watcher.py.
+
+v9.7.2
+======
+
+-  Fixed an issue with ``ocrmypdf.ocr(...language=)`` not accepting a list of
+   languages as documented.
+-  Updated setup.py to confirm that pdfminer.six version 20200402 is supported.
+
+v9.7.1
+======
+
+-  Fixed version check failing when used with qpdf 10.0.0.
+-  Added some missing type annotations.
+-  Updated documentation to warn about need for "ifmain" guard and Windows.

 v9.7.0
 ======
@@ -207,7 +382,7 @@ v9.0.0

 -  Added a high level API for applications that want to integrate OCRmyPDF.
   Special thanks to Martin Wind (@mawi1988) whose made significant contributions
-   to this effort. OCRmyPDF is GPLv3-licensed.
+   to this effort.
 -  Added progress bars for long-running steps. ■■■■■■■□□
 -  We now create linearized ("fast web view") PDFs by default. The new parameter
   ``--fast-web-view`` provides control over when this feature is applied.
@@ -834,8 +1009,8 @@ v6.1.0
 v6.0.0
 ======

-  The software license has been changed to GPLv3. Test resource files
-   and some individual sources may have other licenses.
+-  The software license has been changed to GPLv3 [it has since changed again].
+   Test resource files and some individual sources may have other licenses.
 -  OCRmyPDF now depends on
   `PyMuPDF <https://pymupdf.readthedocs.io/en/latest/installation/>`__.
   Including PyMuPDF is the primary reason for the change to GPLv3.
@@ -1,5 +1,23 @@
 #!/usr/bin/env python3
-# Original version by DeliciousPickle@github; modified
+# Copyright 2016 findingorder: https://github.com/findingorder
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.

 # This script must be edited to meet your needs.

@@ -1,5 +1,26 @@
 # ocrmypdf completion                                     -*- shell-script -*-

+# Copyright 2019 Frank Pille
+# Copyright 2020 Alex Willner
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
 set -o errexit

 _ocrmypdf()
@@ -1,3 +1,23 @@
+# Copyright 2020 James R. Barlow
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
 complete -c ocrmypdf -x -n '__fish_is_first_arg' -l version
 complete -c ocrmypdf -x -n '__fish_is_first_arg' -s h -s "?" -l help

@@ -0,0 +1,58 @@
+# © 2020 James R Barlow: https://github.com/jbarlow83
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.
+
+import logging
+
+from PIL import Image
+
+from ocrmypdf import hookimpl
+
+log = logging.getLogger(__name__)
+
+
+@hookimpl
+def add_options(parser):
+    parser.add_argument('--grayscale-ocr', action='store_true')
+
+
+@hookimpl
+def prepare(options):
+    pass
+
+
+@hookimpl
+def validate(pdfinfo, options):
+    pass
+
+
+@hookimpl
+def filter_ocr_image(page, image):
+    if page.options.grayscale_ocr:
+        log.info("graying")
+        return image.convert('L')
+    return image
+
+
+@hookimpl
+def filter_page_image(page, image_filename):
+    output = image_filename.with_suffix('.jpg')
+    with Image.open(image_filename) as im:
+        im.save(output)
+    return output
@@ -1,5 +1,23 @@
 #!/bin/env python3
-# Contributed by github.com/Enantiomerie
+# Copyright 2017 github.com/Enantiomerie
+#
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+#
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.

 # This script must be edited to meet your needs.

@@ -1,18 +1,23 @@
 # Copyright (C) 2019 Ian Alexander: https://github.com/ianalexander
 # Copyright (C) 2020 James R Barlow: https://github.com/jbarlow83
 #
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
 #
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
+# The above copyright notice and this permission notice shall be included in all
+# copies or substantial portions of the Software.
 #
-# You should have received a copy of the GNU General Public License
-# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+# SOFTWARE.

 import json
 import logging
@@ -25,6 +30,7 @@ from pathlib import Path
 import pikepdf
 from watchdog.events import PatternMatchingEventHandler
 from watchdog.observers import Observer
+from watchdog.observers.polling import PollingObserver

 import ocrmypdf

@@ -32,12 +38,13 @@ import ocrmypdf

 INPUT_DIRECTORY = os.getenv('OCR_INPUT_DIRECTORY', '/input')
 OUTPUT_DIRECTORY = os.getenv('OCR_OUTPUT_DIRECTORY', '/output')
-OUTPUT_DIRECTORY_YEAR_MONTH = bool(os.getenv('OCR_OUTPUT_DIRECTORY_YEAR_MONTH', False))
-ON_SUCCESS_DELETE = bool(os.getenv('OCR_ON_SUCCESS_DELETE', False))
-DESKEW = bool(os.getenv('OCR_DESKEW', False))
+OUTPUT_DIRECTORY_YEAR_MONTH = bool(os.getenv('OCR_OUTPUT_DIRECTORY_YEAR_MONTH', ''))
+ON_SUCCESS_DELETE = bool(os.getenv('OCR_ON_SUCCESS_DELETE', ''))
+DESKEW = bool(os.getenv('OCR_DESKEW', ''))
 OCR_JSON_SETTINGS = json.loads(os.getenv('OCR_JSON_SETTINGS', '{}'))
-POLL_NEW_FILE_SECONDS = os.getenv('OCR_POLL_NEW_FILE_SECONDS', 1)
-LOGLEVEL = os.environ.get('OCR_LOGLEVEL', 'INFO').upper()
+POLL_NEW_FILE_SECONDS = int(os.getenv('OCR_POLL_NEW_FILE_SECONDS', '1'))
+USE_POLLING = bool(os.getenv('OCR_USE_POLLING', ''))
+LOGLEVEL = os.getenv('OCR_LOGLEVEL', 'INFO').upper()
 PATTERNS = ['*.pdf']

 log = logging.getLogger('ocrmypdf-watcher')
@@ -112,6 +119,7 @@ def main():
    ocrmypdf.configure_logging(
        verbosity=ocrmypdf.Verbosity.default, manage_root_logger=True
    )
+    log.setLevel(LOGLEVEL)
    log.info(
        f"Starting OCRmyPDF watcher with config:\n"
        f"Input Directory: {INPUT_DIRECTORY}\n"
@@ -126,6 +134,7 @@ def main():
        f"DESKEW: {DESKEW}\n"
        f"ARGS: {OCR_JSON_SETTINGS}\n"
        f"POLL_NEW_FILE_SECONDS: {POLL_NEW_FILE_SECONDS}\n"
+        f"USE_POLLING: {USE_POLLING}\n"
        f"LOGLEVEL: {LOGLEVEL}\n"
    )

@@ -134,7 +143,10 @@ def main():
        sys.exit(1)

    handler = HandleObserverEvent(patterns=PATTERNS)
-    observer = Observer()
+    if USE_POLLING:
+        observer = PollingObserver()
+    else:
+        observer = Observer()
    observer.schedule(handler, INPUT_DIRECTORY, recursive=True)
    observer.start()
    try:
@@ -10,8 +10,7 @@ build-backend = "setuptools.build_meta"

 [tool.black]
 line-length = 88
-target-version = ["py36",
-"py37", "py38"]
+target-version = ["py36", "py37", "py38"]
 skip-string-normalization = true
 include = '\.pyi?$'
 exclude = '''
@@ -1,2 +0,0 @@
-twine >= 1.8.1
-coverage >= 4.5
@@ -2,9 +2,11 @@
 # setup.py lists a separate set of requirements that are looser to simplify
 # installation
 cffi == 1.14.0
-img2pdf == 0.3.3
-pdfminer.six == 20200124
-pikepdf == 1.10.2
-Pillow == 7.0.0
-reportlab == 3.5.34
-tqdm == 4.42.1
+coloredlogs == 14.0  # technically optional
+img2pdf == 0.3.6
+pdfminer.six == 20200517
+pikepdf == 1.16.1
+pluggy == 0.13.1
+Pillow == 7.1.2
+reportlab == 3.5.42
+tqdm == 4.46.1
@@ -1,7 +1,7 @@
 pytest >= 5.0.0
 pytest-helpers-namespace >= 2019.1.8
 pytest-xdist >= 1.31.0
-pytest-cov >= 2.8.0
+pytest-cov >= 2.10.0
 python-xmp-toolkit == 2.0.1  # requires apt-get install libexempi3
                     # or brew install exempi
 #PyMuPDF == 1.13.4    # optional
@@ -1 +1 @@
-watchdog >= 0.8.2, < 1.0
+watchdog == 0.10.2
@@ -23,7 +23,7 @@ force_grid_wrap=0
 use_parentheses=True
 line_length=88
 known_first_party = ocrmypdf
-known_third_party = PIL,_cffi_backend,cffi,flask,gs,img2pdf,pdfminer,pikepdf,pkg_resources,pytest,reportlab,setuptools,sphinx_rtd_theme,tqdm,watchdog,werkzeug
+known_third_party = PIL,_cffi_backend,cffi,flask,img2pdf,pdfminer,pikepdf,pkg_resources,pluggy,pytest,reportlab,setuptools,sphinx_rtd_theme,tqdm,watchdog,werkzeug

 [metadata]
 license_file = LICENSE
@@ -2,20 +2,10 @@
 # -*- coding: utf-8 -*-
 # © 2015 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 from __future__ import print_function, unicode_literals

@@ -27,22 +17,6 @@ if sys.version_info < (3, 6):
    print("Python 3.6 or newer is required", file=sys.stderr)
    sys.exit(1)

-
-# pylint: disable=w0613
-
-
-command = next((arg for arg in sys.argv[1:] if not arg.startswith('-')), '')
-if command.startswith('install') or command in [
-    'check',
-    'test',
-    'nosetests',
-    'easy_install',
-]:
-    forced = '--force' in sys.argv
-    if forced:
-        print("The argument --force is deprecated. Please discontinue use.")
-
-
 if 'upload' in sys.argv[1:]:
    print('Use twine to upload the package - setup.py upload is insecure')
    sys.exit(1)
@@ -62,7 +36,7 @@ setup(
    long_description_content_type='text/markdown',
    url='https://github.com/jbarlow83/OCRmyPDF',
    author='James R. Barlow',
-    author_email='jim@purplerock.ca',
+    author_email='james@purplerock.ca',
    packages=find_packages('src', exclude=["tests", "tests.*"]),
    package_dir={'': 'src'},
    keywords=['PDF', 'OCR', 'optical character recognition', 'PDF/A', 'scanning'],
@@ -70,12 +44,13 @@ setup(
        "Programming Language :: Python :: 3.6",
        "Programming Language :: Python :: 3.7",
        "Programming Language :: Python :: 3.8",
+        "Programming Language :: Python :: 3.9",
        "Development Status :: 5 - Production/Stable",
        "Environment :: Console",
        "Intended Audience :: End Users/Desktop",
        "Intended Audience :: Science/Research",
        "Intended Audience :: System Administrators",
-        "License :: OSI Approved :: GNU General Public License v3 (GPLv3)",
+        "License :: OSI Approved :: Mozilla Public License 2.0 (MPL 2.0)",
        "Operating System :: MacOS :: MacOS X",
        "Operating System :: Microsoft :: Windows :: Windows 10",
        "Operating System :: POSIX",
@@ -95,12 +70,13 @@ setup(
    use_scm_version={'version_scheme': 'post-release'},
    cffi_modules=['src/ocrmypdf/lib/compile_leptonica.py:ffibuilder'],
    install_requires=[
-        'chardet >= 3.0.4, < 4',  # unlisted requirement of pdfminer.six 20181108
        'cffi >= 1.9.1',  # must be a setup and install requirement
+        'coloredlogs >= 14.0',  # strictly optional
        'img2pdf >= 0.3.0, < 0.4',  # pure Python, so track HEAD closely
-        'pdfminer.six >= 20181108, <= 20200124',
-        'pikepdf >= 1.8.1, < 2',
-        'Pillow >= 6.2.0',
+        'pdfminer.six >= 20191110, <= 20200726',
+        'pikepdf >= 1.14.0, < 2',
+        'Pillow >= 7.0.0',
+        'pluggy >= 0.13.0',
        'reportlab >= 3.3.0',  # oldest released version with sane image handling
        'tqdm >= 4',
    ],
@@ -1,24 +1,16 @@
 # © 2017 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.

-from . import helpers, hocrtransform, leptonica, pdfa, pdfinfo
-from ._version import PROGRAM_NAME, __version__
-from .api import Verbosity, configure_logging, ocr
-from .exceptions import (
+
+from pluggy import HookimplMarker as _HookimplMarker
+
+from ocrmypdf import helpers, hocrtransform, leptonica, pdfa, pdfinfo
+from ocrmypdf._version import PROGRAM_NAME, __version__
+from ocrmypdf.api import Verbosity, configure_logging, ocr
+from ocrmypdf.exceptions import (
    BadArgsError,
    DpiError,
    EncryptedPdfError,
@@ -33,3 +25,6 @@ from .exceptions import (
    TesseractConfigError,
    UnsupportedImageFormatError,
 )
+from ocrmypdf.pluginspec import OcrEngine, OrientationConfidence
+
+hookimpl = _HookimplMarker('ocrmypdf')
@@ -1,36 +1,38 @@
 #!/usr/bin/env python3
 # © 2015-19 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import logging
 import os
+import signal
 import sys
+from multiprocessing import set_start_method

-from . import __version__
-from ._jobcontext import make_logger
-from ._sync import run_pipeline
-from ._validation import check_closed_streams, check_options
-from .api import Verbosity, configure_logging
-from .cli import parser
-from .exceptions import BadArgsError, ExitCode, MissingDependencyError
+from ocrmypdf import __version__
+from ocrmypdf._plugin_manager import get_parser_options_plugins
+from ocrmypdf._sync import run_pipeline
+from ocrmypdf._validation import check_closed_streams, check_options
+from ocrmypdf.api import Verbosity, configure_logging
+from ocrmypdf.exceptions import (
+    BadArgsError,
+    ExitCode,
+    InputFileError,
+    MissingDependencyError,
+)
+
+log = logging.getLogger('ocrmypdf')
+
+
+def sigbus(*args):
+    raise InputFileError("Lost access to the input file")


 def run(args=None):
-    options = parser.parse_args(args=args)
+    _parser, options, plugin_manager = get_parser_options_plugins(args=args)

    if not check_closed_streams(options):
        return ExitCode.bad_args
@@ -47,10 +49,9 @@ def run(args=None):
    configure_logging(
        verbosity, progress_bar_friendly=options.progress_bar, manage_root_logger=True
    )
-    log = make_logger('ocrmypdf')
-    log.debug('ocrmypdf ' + __version__)
+    log.debug('ocrmypdf %s', __version__)
    try:
-        check_options(options)
+        check_options(options, plugin_manager)
    except ValueError as e:
        log.error(e)
        return ExitCode.bad_args
@@ -61,9 +62,14 @@ def run(args=None):
        log.error(e)
        return ExitCode.missing_dependency

-    result = run_pipeline(options=options)
+    if hasattr(signal, 'SIGBUS'):
+        signal.signal(signal.SIGBUS, sigbus)
+
+    result = run_pipeline(options=options, plugin_manager=plugin_manager)
    return result


 if __name__ == '__main__':
+    if sys.platform == 'darwin' and sys.version_info < (3, 8):
+        set_start_method('spawn')  # see python bpo-33725
    sys.exit(run())
@@ -0,0 +1,138 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+import logging
+import logging.handlers
+import multiprocessing
+import os
+import signal
+import sys
+import threading
+from multiprocessing import Pool as ProcessPool
+from multiprocessing.dummy import Pool as ThreadPool
+from typing import Callable, Iterable, Optional
+
+from tqdm import tqdm
+
+from ocrmypdf.exceptions import InputFileError
+
+
+def log_listener(queue):
+    """Listen to the worker processes and forward the messages to logging
+
+    For simplicity this is a thread rather than a process. Only one process
+    should actually write to sys.stderr or whatever we're using, so if this is
+    made into a process the main application needs to be directed to it.
+
+    See https://docs.python.org/3/howto/logging-cookbook.html#logging-to-a-single-file-from-multiple-processes
+    """
+
+    while True:
+        try:
+            record = queue.get()
+            if record is None:
+                break
+            logger = logging.getLogger(record.name)
+            logger.handle(record)
+        except Exception:  # pylint: disable=broad-except
+            import traceback  # pylint: disable=import-outside-toplevel
+
+            print("Logging problem", file=sys.stderr)
+            traceback.print_exc(file=sys.stderr)
+
+
+def process_sigbus(*args):
+    raise InputFileError("A worker process lost access to an input file")
+
+
+def process_init(queue, user_init):
+    """Initialize a process pool worker"""
+
+    # Ignore SIGINT (our parent process will kill us gracefully)
+    signal.signal(signal.SIGINT, signal.SIG_IGN)
+
+    # Install SIGBUS handler (so our parent process can abort somewhat gracefully)
+    if hasattr(signal, 'SIGBUS'):
+        signal.signal(signal.SIGBUS, process_sigbus)
+
+    # Reconfigure the root logger for this process to send all messages to a queue
+    h = logging.handlers.QueueHandler(queue)
+    root = logging.getLogger()
+    root.handlers = []
+    root.addHandler(h)
+
+    if user_init:
+        user_init()
+
+
+def thread_init(_queue, user_init):
+    # As a thread, block SIGBUS so the main thread deals with it...
+    if hasattr(signal, 'SIGBUS'):
+        signal.pthread_sigmask(signal.SIG_BLOCK, {signal.SIGBUS})
+    if user_init:
+        user_init()
+
+
+def exec_progress_pool(
+    *,
+    use_threads: bool,
+    max_workers: int,
+    tqdm_kwargs: dict,
+    task_initializer: Optional[Callable] = None,
+    task: Optional[Callable] = None,
+    task_arguments: Optional[Iterable] = None,
+    task_finished: Optional[Callable] = None,
+):
+    log_queue: multiprocessing.Queue = multiprocessing.Queue(-1)
+    listener = threading.Thread(target=log_listener, args=(log_queue,))
+
+    if use_threads:
+        pool_class = ThreadPool
+        initializer = thread_init
+    else:
+        pool_class = ProcessPool
+        initializer = process_init
+    listener.start()
+
+    with tqdm(**tqdm_kwargs) as pbar:
+        pool = pool_class(
+            processes=max_workers,
+            initializer=initializer,
+            initargs=(log_queue, task_initializer),
+        )
+        try:
+            results = pool.imap_unordered(task, task_arguments)
+            while True:
+                try:
+                    result = results.next()
+                    if task_finished:
+                        task_finished(result, pbar)
+                    else:
+                        pbar.update()
+                except StopIteration:
+                    break
+        except KeyboardInterrupt:
+            # Terminate pool so we exit instantly
+            pool.terminate()
+            # Don't try listener.join() here, will deadlock
+            raise
+        except Exception:
+            if not os.environ.get("PYTEST_CURRENT_TEST", ""):
+                # Unless inside pytest, exit immediately because no one wants
+                # to wait for child processes to finalize results that will be
+                # thrown away. Inside pytest, we want child processes to exit
+                # cleanly so that they output an error messages or coverage data
+                # we need from them.
+                pool.terminate()
+            raise
+        finally:
+            # Terminate log listener
+            log_queue.put_nowait(None)
+            pool.close()
+            pool.join()
+
+    listener.join()
@@ -0,0 +1,8 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+"""Manage third party executables"""
@@ -1,47 +1,36 @@
 # © 2017 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """Interface to Ghostscript executable"""

 import logging
 import os
 import re
-import warnings
-from contextlib import suppress
-from functools import lru_cache
 from io import BytesIO
 from os import fspath
 from pathlib import Path
 from shutil import which
 from subprocess import PIPE, CalledProcessError
+from typing import Optional, cast

 from PIL import Image

-from ..exceptions import MissingDependencyError, SubprocessOutputError
-from . import get_version, run
+from ocrmypdf.exceptions import MissingDependencyError, SubprocessOutputError
+from ocrmypdf.helpers import Resolution
+from ocrmypdf.subprocess import get_version, run

-gslog = logging.getLogger()
+log = logging.getLogger(__name__)

-GS = 'gs'
+_gswin = None
 if os.name == 'nt':
-    GS = which('gswin64c')
-    if not GS:
-        GS = which('gswin32c')
-        if not GS:
+    _gswin = which('gswin64c')
+    if not _gswin:
+        _gswin = which('gswin32c')
+        if not _gswin:
            raise MissingDependencyError(
                """
                ---------------------------------------------------------------------
@@ -54,15 +43,17 @@ if os.name == 'nt':
                ---------------------------------------------------------------------
                """
            )
-    GS = Path(GS).stem
+    _gswin = Path(_gswin).stem
+
+GS = _gswin if _gswin else 'gs'
+del _gswin


-@lru_cache(maxsize=1)
 def version():
    return get_version(GS)


-def jpeg_passthrough_available():
+def jpeg_passthrough_available() -> bool:
    """Returns True if the installed version of Ghostscript supports JPEG passthru

    Prior to 9.23, Ghostscript decode and re-encoded JPEGs internally. In 9.23
@@ -79,94 +70,25 @@ def jpeg_passthrough_available():
    return version() >= '9.24'


-def _gs_error_reported(stream):
-    return re.search(r'error', stream, flags=re.IGNORECASE)
-
-
-def extract_text(input_file, pageno=1):
-    """Use the txtwrite device to get text layout information out
-
-    For details on options of -dTextFormat see
-    https://www.ghostscript.com/doc/current/VectorDevices.htm#TXT
-
-    Format is like
-    <page>
-    <line>
-    <span bbox="left top right bottom" font="..." size="...">
-    <char bbox="...." c="X"/>
-
-    :param pageno: number of page to extract, or all pages if None
-    :return: XML-ish text representation in bytes
-    """
-
-    if pageno is not None:
-        pages = ['-dFirstPage=%i' % pageno, '-dLastPage=%i' % pageno]
-    else:
-        pages = []
-
-    # Note due to bug https://bugs.ghostscript.com/show_bug.cgi?id=701971
-    # Ghostscript <= 9.50 will truncate output unless we write to stdout, so
-    # don't write to a file.
-    args_gs = (
-        [
-            GS,
-            '-dQUIET',
-            '-dSAFER',
-            '-dBATCH',
-            '-dNOPAUSE',
-            '-sDEVICE=txtwrite',
-            '-dTextFormat=0',
-        ]
-        + pages
-        + ['-o', '-', fspath(input_file), "-sstdout=%stderr"]
-    )
-
-    try:
-        p = run(args_gs, stdout=PIPE, stderr=PIPE, check=True)
-    except CalledProcessError as e:
-        raise SubprocessOutputError(
-            'Ghostscript text extraction failed\n%s\n%s'
-            % (input_file, e.stderr.decode(errors='replace'))
-        )
-
-    return p.stdout
+def _gs_error_reported(stream) -> bool:
+    return True if re.search(r'error', stream, flags=re.IGNORECASE) else False


 def rasterize_pdf(
-    input_file,
-    output_file,
-    xres,
-    yres,
-    raster_device,
-    log,
-    pageno=1,
-    page_dpi=None,
-    rotation=None,
-    filter_vector=False,
+    input_file: os.PathLike,
+    output_file: os.PathLike,
+    *,
+    raster_device: str,
+    raster_dpi: Resolution,
+    pageno: int = 1,
+    page_dpi: Resolution = None,
+    rotation: int = None,
+    filter_vector: bool = False,
 ):
-    """Rasterize one page of a PDF at resolution (xres, yres) in canvas units.
-
-    The image is sized to match the integer pixels dimensions implied by
-    (xres, yres) even if those numbers are noninteger. The image's DPI will
-     be overridden with the values in page_dpi.
-
-    :param input_file: pathlike
-    :param output_file: pathlike
-    :param xres: resolution at which to rasterize page
-    :param yres:
-    :param raster_device:
-    :param log:
-    :param pageno: page number to rasterize (beginning at page 1)
-    :param page_dpi: resolution tuple (x, y) overriding output image DPI
-    :param rotation: 0, 90, 180, 270: clockwise angle to rotate page
-    :param filter_vector: if True, remove vector graphics objects
-    :return:
-    """
-    res = round(xres, 6), round(yres, 6)
+    """Rasterize one page of a PDF at resolution raster_dpi in canvas units."""
+    raster_dpi = raster_dpi.round(6)
    if not page_dpi:
-        page_dpi = res
-    if not log:
-        log = gslog
+        page_dpi = raster_dpi

    args_gs = (
        [
@@ -178,7 +100,7 @@ def rasterize_pdf(
            f'-sDEVICE={raster_device}',
            f'-dFirstPage={pageno}',
            f'-dLastPage={pageno}',
-            f'-r{res[0]:f}x{res[1]:f}',
+            f'-r{raster_dpi.x:f}x{raster_dpi.y:f}',
        ]
        + (['-dFILTERVECTOR'] if filter_vector else [])
        + [
@@ -191,7 +113,6 @@ def rasterize_pdf(
        ]
    )

-    log.debug(args_gs)
    try:
        p = run(args_gs, stdout=PIPE, stderr=PIPE, check=True)
    except CalledProcessError as e:
@@ -216,43 +137,17 @@ def rasterize_pdf(
            elif rotation == 270:
                im = im.transpose(Image.ROTATE_270)
            if rotation % 180 == 90:
-                page_dpi = page_dpi[1], page_dpi[0]
+                page_dpi = page_dpi.flip_axis()
        im.save(fspath(output_file), dpi=page_dpi)


 def generate_pdfa(
    pdf_pages,
-    output_file,
-    compression,
-    log,
-    threads=None,  # deprecated parameter
-    pdf_version='1.5',
-    pdfa_part='2',
+    output_file: os.PathLike,
+    compression: str,
+    pdf_version: str = '1.5',
+    pdfa_part: str = '2',
 ):
-    """Generate a PDF/A.
-
-    The pdf_pages, a list files, will be merged into output_file. One or more
-    PDF files may be merged. One of the files in this list must be a pdfmark
-    file that provides Ghostscript with details on how to perform the PDF/A
-    conversion. By default with we pick PDF/A-2b, but this works for 1 or 3.
-
-    compression can be 'jpeg', 'lossless', or an empty string. In 'jpeg',
-    Ghostscript is instructed to convert color and grayscale images to DCT
-    (JPEG encoding). In 'lossless' Ghostscript is told to convert images to
-    Flate (lossless/PNG). If the parameter is omitted Ghostscript is left to
-    make its own decisions about how to encode images; it appears to use a
-    heuristic to decide how to encode images. As of Ghostscript 9.25, we
-    support passthrough JPEG which allows Ghostscript to avoid transcoding
-    images entirely. (The feature was added in 9.23 but broken, and the 9.24
-    release of Ghostscript had regressions, so we don't support it until 9.25.)
-    """
-    if not log:
-        log = gslog
-    if threads is not None:
-        warnings.warn(
-            "use of deprecated parameter 'threads'", category=DeprecationWarning
-        )
-
    compression_args = []
    if compression == 'jpeg':
        compression_args = [
@@ -1,30 +1,18 @@
 # © 2018 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """Interface to jbig2 executable"""

-from functools import lru_cache
 from subprocess import PIPE

-from ..exceptions import MissingDependencyError
-from . import get_version, run
+from ocrmypdf.exceptions import MissingDependencyError
+from ocrmypdf.subprocess import get_version, run


-@lru_cache(maxsize=1)
 def version():
    return get_version('jbig2', regex=r'jbig2enc (\d+(\.\d+)*).*')

@@ -1,33 +1,21 @@
 # © 2018 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """Interface to pngquant executable"""

-from functools import lru_cache
-from subprocess import run
+from os import fspath
 from tempfile import NamedTemporaryFile

 from PIL import Image

-from ..exceptions import MissingDependencyError
-from . import get_version
+from ocrmypdf.exceptions import MissingDependencyError
+from ocrmypdf.subprocess import get_version, run


-@lru_cache(maxsize=1)
 def version():
    return get_version('pngquant', regex=r'(\d+(\.\d+)*).*')

@@ -41,6 +29,8 @@ def available():


 def quantize(input_file, output_file, quality_min, quality_max):
+    input_file = fspath(input_file)
+    output_file = fspath(output_file)
    if input_file.endswith('.jpg'):
        with Image.open(input_file) as im, NamedTemporaryFile(suffix='.png') as tmp:
            im.save(tmp)
@@ -1,19 +1,9 @@
 # © 2017 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """Interface to Tesseract executable"""

@@ -21,17 +11,21 @@ import logging
 import os
 import shutil
 from collections import namedtuple
-from contextlib import suppress
 from os import fspath
+from pathlib import Path
 from subprocess import PIPE, STDOUT, CalledProcessError, TimeoutExpired
+from typing import List

-from ..exceptions import (
+from PIL import Image
+
+from ocrmypdf.exceptions import (
    MissingDependencyError,
    SubprocessOutputError,
    TesseractConfigError,
 )
-from ..helpers import page_number, safe_symlink
-from . import get_version, run
+from ocrmypdf.subprocess import get_version, run
+
+log = logging.getLogger(__name__)

 OrientationConfidence = namedtuple('OrientationConfidence', ('angle', 'confidence'))

@@ -59,16 +53,11 @@ class TesseractLoggerAdapter(logging.LoggerAdapter):
        return '[tesseract] %s' % (msg), kwargs


-def version(tesseract_env=None):
-    return get_version('tesseract', regex=r'tesseract\s(.+)', env=tesseract_env)
+def version():
+    return get_version('tesseract', regex=r'tesseract\s(.+)')


-def v4(tesseract_env=None):
-    "Is this Tesseract v4.0?"
-    return version(tesseract_env) >= '4'
-
-
-def has_textonly_pdf(tesseract_env=None, langs=None):
+def has_textonly_pdf(langs=None):
    """Does Tesseract have textonly_pdf capability?

    Available in v4.00.00alpha since January 2017. Best to
@@ -77,34 +66,28 @@ def has_textonly_pdf(tesseract_env=None, langs=None):
    args_tess = tess_base_args(langs, engine_mode=None) + ['--print-parameters', 'pdf']
    params = ''
    try:
-        proc = run(
-            args_tess,
-            check=True,
-            universal_newlines=True,
-            stdout=PIPE,
-            stderr=STDOUT,
-            env=tesseract_env,
-        )
+        proc = run(args_tess, check=True, stdout=PIPE, stderr=STDOUT)
        params = proc.stdout
    except CalledProcessError as e:
        raise MissingDependencyError(
-            "Could not --print-parameters from tesseract"
+            "Could not --print-parameters from tesseract. This can happen if the "
+            "TESSDATA_PREFIX environment is not set to a valid tessdata folder. "
        ) from e
-    if 'textonly_pdf' in params:
+    if b'textonly_pdf' in params:
        return True
    return False


-def has_user_words(tesseract_env=None):
+def has_user_words():
    """Does Tesseract have --user-words capability?

    Not available in 4.0, but available in 4.1. Also available in 3.x, but
    we no longer support 3.x.
    """
-    return version(tesseract_env) >= '4.1'
+    return version() >= '4.1'


-def languages(tesseract_env=None):
+def get_languages():
    def lang_error(output):
        msg = (
            "Tesseract failed to report available languages.\n"
@@ -117,12 +100,7 @@ def languages(tesseract_env=None):
    args_tess = ['tesseract', '--list-langs']
    try:
        proc = run(
-            args_tess,
-            universal_newlines=True,
-            stdout=PIPE,
-            stderr=STDOUT,
-            check=True,
-            env=tesseract_env,
+            args_tess, universal_newlines=True, stdout=PIPE, stderr=STDOUT, check=True
        )
        output = proc.stdout
    except CalledProcessError as e:
@@ -131,11 +109,11 @@ def languages(tesseract_env=None):
    for line in output.splitlines():
        if line.startswith('Error'):
            raise MissingDependencyError(lang_error(output))
-    header, *rest = output.splitlines()
+    _header, *rest = output.splitlines()
    return set(lang.strip() for lang in rest)


-def tess_base_args(langs, engine_mode):
+def tess_base_args(langs: List[str], engine_mode: int) -> List[str]:
    args = ['tesseract']
    if langs:
        args.extend(['-l', '+'.join(langs)])
@@ -144,7 +122,7 @@ def tess_base_args(langs, engine_mode):
    return args


-def get_orientation(input_file, engine_mode, timeout: float, log, tesseract_env=None):
+def get_orientation(input_file: Path, engine_mode: int, timeout: float):
    args_tesseract = tess_base_args(['osd'], engine_mode) + [
        '--psm',
        '0',
@@ -153,19 +131,13 @@ def get_orientation(input_file, engine_mode, timeout: float, log, tesseract_env=
    ]

    try:
-        p = run(
-            args_tesseract,
-            stdout=PIPE,
-            stderr=STDOUT,
-            timeout=timeout,
-            check=True,
-            env=tesseract_env,
-        )
+        p = run(args_tesseract, stdout=PIPE, stderr=STDOUT, timeout=timeout, check=True)
        stdout = p.stdout
    except TimeoutExpired:
        return OrientationConfidence(angle=0, confidence=0.0)
    except CalledProcessError as e:
-        tesseract_log_output(log, e.output, input_file)
+        tesseract_log_output(e.stdout)
+        tesseract_log_output(e.stderr)
        if (
            b'Too few characters. Skipping this page' in e.output
            or b'Image too large' in e.output
@@ -187,15 +159,17 @@ def get_orientation(input_file, engine_mode, timeout: float, log, tesseract_env=
        return oc


-def tesseract_log_output(mainlog, stdout, input_file):
-    log = TesseractLoggerAdapter(
-        mainlog, extra=mainlog.extra if hasattr(mainlog, 'extra') else None
+def tesseract_log_output(stream):
+    tlog = TesseractLoggerAdapter(
+        log, extra=log.extra if hasattr(log, 'extra') else None
    )

+    if not stream:
+        return
    try:
-        text = stdout.decode()
+        text = stream.decode()
    except UnicodeDecodeError:
-        text = stdout.decode('utf-8', 'ignore')
+        text = stream.decode('utf-8', 'ignore')

    lines = text.splitlines()
    for line in lines:
@@ -204,67 +178,58 @@ def tesseract_log_output(mainlog, stdout, input_file):
        elif line.startswith("Warning in pixReadMem"):
            continue
        elif 'diacritics' in line:
-            log.warning("lots of diacritics - possibly poor OCR")
+            tlog.warning("lots of diacritics - possibly poor OCR")
        elif line.startswith('OSD: Weak margin'):
-            log.warning("unsure about page orientation")
+            tlog.warning("unsure about page orientation")
        elif 'Error in pixScanForForeground' in line:
            pass  # Appears to be spurious/problem with nonwhite borders
        elif 'Error in boxClipToRectangle' in line:
            pass  # Always appears with pixScanForForeground message
        elif 'parameter not found: ' in line.lower():
-            log.error(line.strip())
+            tlog.error(line.strip())
            problem = line.split('found: ')[1]
            raise TesseractConfigError(problem)
        elif 'error' in line.lower() or 'exception' in line.lower():
-            log.error(line.strip())
+            tlog.error(line.strip())
        elif 'warning' in line.lower():
-            log.warning(line.strip())
+            tlog.warning(line.strip())
        elif 'read_params_file' in line.lower():
-            log.error(line.strip())
+            tlog.error(line.strip())
        else:
-            log.info(line.strip())
+            tlog.info(line.strip())


-def page_timedout(log, input_file, timeout):
+def page_timedout(timeout):
    if timeout == 0:
        return
-    prefix = f"{(page_number(input_file)):4d}: [tesseract] "
-    log.warning(prefix + " took too long to OCR - skipping")
+    log.warning("[tesseract] took too long to OCR - skipping")


-def _generate_null_hocr(output_hocr, output_sidecar, image):
+def _generate_null_hocr(output_hocr, output_text, image):
    """Produce a .hocr file that reports no text detected on a page that is
    the same size as the input image."""
-    from PIL import Image
-
    with Image.open(image) as im:
        w, h = im.size

-    with open(output_hocr, 'w', encoding="utf-8") as f:
-        f.write(HOCR_TEMPLATE.format(w, h))
-    with open(output_sidecar, 'w', encoding='utf-8') as f:
-        f.write('[skipped page]')
+    output_hocr.write_text(HOCR_TEMPLATE.format(w, h), encoding='utf-8')
+    output_text.write_text('[skipped page]', encoding='utf-8')


 def generate_hocr(
-    input_file,
-    output_files,
-    language: list,
-    engine_mode,
-    tessconfig: list,
+    input_file: Path,
+    output_hocr: Path,
+    output_text: Path,
+    languages: List[str],
+    engine_mode: int,
+    tessconfig: List[str],
    timeout: float,
    pagesegmode: int,
    user_words,
    user_patterns,
-    tesseract_env,
-    log,
 ):
+    prefix = output_hocr.with_suffix('')

-    output_hocr = next(o for o in output_files if fspath(o).endswith('.hocr'))
-    output_sidecar = next(o for o in output_files if fspath(o).endswith('.txt'))
-    prefix = os.path.splitext(output_hocr)[0]
-
-    args_tesseract = tess_base_args(language, engine_mode)
+    args_tesseract = tess_base_args(languages, engine_mode)

    if pagesegmode is not None:
        args_tesseract.extend(['--psm', str(pagesegmode)])
@@ -275,94 +240,70 @@ def generate_hocr(
    if user_patterns:
        args_tesseract.extend(['--user-patterns', user_patterns])

-    # Reminder: test suite tesseract spoofers will break after any changes
+    # Reminder: test suite tesseract test plugins will break after any changes
    # to the number of order parameters here
    args_tesseract.extend([input_file, prefix, 'hocr', 'txt'] + tessconfig)
    try:
-        p = run(
-            args_tesseract,
-            stdout=PIPE,
-            stderr=STDOUT,
-            timeout=timeout,
-            check=True,
-            env=tesseract_env,
-        )
+        p = run(args_tesseract, stdout=PIPE, stderr=STDOUT, timeout=timeout, check=True)
        stdout = p.stdout
    except TimeoutExpired:
        # Generate a HOCR file with no recognized text if tesseract times out
        # Temporary workaround to hocrTransform not being able to function if
        # it does not have a valid hOCR file.
-        page_timedout(log, input_file, timeout)
-        _generate_null_hocr(output_hocr, output_sidecar, input_file)
+        page_timedout(timeout)
+        _generate_null_hocr(output_hocr, output_text, input_file)
    except CalledProcessError as e:
-        tesseract_log_output(log, e.output, input_file)
+        tesseract_log_output(e.output)
        if b'Image too large' in e.output:
-            _generate_null_hocr(output_hocr, output_sidecar, input_file)
+            _generate_null_hocr(output_hocr, output_text, input_file)
            return

        raise SubprocessOutputError() from e
    else:
-        tesseract_log_output(log, stdout, input_file)
+        tesseract_log_output(stdout)
        # The sidecar text file will get the suffix .txt; rename it to
        # whatever caller wants it named
-        if os.path.exists(prefix + '.txt'):
-            shutil.move(prefix + '.txt', output_sidecar)
+        if prefix.with_suffix('.txt').exists():
+            shutil.move(prefix.with_suffix('.txt'), output_text)


-def use_skip_page(text_only, skip_pdf, output_pdf, output_text):
-    with open(output_text, 'w') as f:
-        f.write('[skipped page]')
+def use_skip_page(output_pdf, output_text):
+    output_text.write_text('[skipped page]', encoding='utf-8')

-    if skip_pdf and not text_only:
-        # Substitute a "skipped page"
-        with suppress(FileNotFoundError):
-            os.remove(output_pdf)  # In case it was partially created
-        safe_symlink(skip_pdf, output_pdf)
-        return
-
-    # Or normally, just write a 0 byte file to the output to indicate a skip
-    with open(output_pdf, 'wb') as out:
-        out.write(b'')
+    # A 0 byte file to the output to indicate a skip
+    output_pdf.write_bytes(b'')


 def generate_pdf(
    *,
-    input_image,
-    skip_pdf=None,
-    output_pdf,
-    output_text,
-    language: list,
-    engine_mode,
-    text_only: bool,
-    tessconfig: list,
+    input_file: Path,
+    output_pdf: Path,
+    output_text: Path,
+    languages: List[str],
+    engine_mode: int,
+    tessconfig: List[str],
    timeout: float,
    pagesegmode: int,
    user_words,
    user_patterns,
-    tesseract_env,
-    log,
 ):
    """Use Tesseract to render a PDF.

-    input_image -- image to analyze
-    skip_pdf -- if we time out, use this file as output
+    input_file -- image to analyze
    output_pdf -- file to generate
    output_text -- OCR text file
-    language -- list of languages to consider
+    languages -- list of languages to consider
    engine_mode -- engine mode argument for tess v4
-    text_only -- enable tesseract text only mode?
    tessconfig -- tesseract configuration
    timeout -- timeout (seconds)
-    log -- logger object
    """

-    args_tesseract = tess_base_args(language, engine_mode)
+    args_tesseract = tess_base_args(languages, engine_mode)

    if pagesegmode is not None:
        args_tesseract.extend(['--psm', str(pagesegmode)])

-    if text_only and has_textonly_pdf(tesseract_env, language):
-        args_tesseract.extend(['-c', 'textonly_pdf=1'])
+    args_tesseract.extend(['-c', 'textonly_pdf=1'])

    if user_words:
        args_tesseract.extend(['--user-words', user_words])
@@ -372,30 +313,23 @@ def generate_pdf(

    prefix = os.path.splitext(output_pdf)[0]  # Tesseract appends suffixes

-    # Reminder: test suite tesseract spoofers might break after any changes
+    # Reminder: test suite tesseract test plugins might break after any changes
    # to the number of order parameters here

-    args_tesseract.extend([input_image, prefix, 'pdf', 'txt'] + tessconfig)
+    args_tesseract.extend([input_file, prefix, 'pdf', 'txt'] + tessconfig)
    try:
-        p = run(
-            args_tesseract,
-            stdout=PIPE,
-            stderr=STDOUT,
-            timeout=timeout,
-            check=True,
-            env=tesseract_env,
-        )
+        p = run(args_tesseract, stdout=PIPE, stderr=STDOUT, timeout=timeout, check=True)
        stdout = p.stdout
        if os.path.exists(prefix + '.txt'):
            shutil.move(prefix + '.txt', output_text)
    except TimeoutExpired:
-        page_timedout(log, input_image, timeout)
-        use_skip_page(text_only, skip_pdf, output_pdf, output_text)
+        page_timedout(timeout)
+        use_skip_page(output_pdf, output_text)
    except CalledProcessError as e:
-        tesseract_log_output(log, e.output, input_image)
+        tesseract_log_output(e.output)
        if b'Image too large' in e.output:
-            use_skip_page(text_only, skip_pdf, output_pdf, output_text)
+            use_skip_page(output_pdf, output_text)
            return
        raise SubprocessOutputError() from e
    else:
-        tesseract_log_output(log, stdout, input_image)
+        tesseract_log_output(stdout)
@@ -1,50 +1,41 @@
 # © 2015 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 # unpaper documentation:
 # https://github.com/Flameeyes/unpaper/blob/master/doc/basic-concepts.md

 """Interface to unpaper executable"""

+import logging
 import os
 import shlex
-from functools import lru_cache
+from pathlib import Path
 from subprocess import PIPE, STDOUT, CalledProcessError
 from tempfile import TemporaryDirectory
+from typing import Tuple

 from PIL import Image

-from ..exceptions import MissingDependencyError, SubprocessOutputError
-from . import get_version
-from . import run as external_run
+from ocrmypdf.exceptions import MissingDependencyError, SubprocessOutputError
+from ocrmypdf.subprocess import get_version
+from ocrmypdf.subprocess import run as external_run
+
+log = logging.getLogger(__name__)


-@lru_cache(maxsize=1)
 def version():
    return get_version('unpaper')


-def run(input_file, output_file, dpi, log, mode_args):
-    args_unpaper = ['unpaper', '-v', '--dpi', str(dpi)] + mode_args
-
+def _setup_unpaper_io(tmpdir: Path, input_file: Path) -> Tuple[Path, Path]:
    SUFFIXES = {'1': '.pbm', 'L': '.pgm', 'RGB': '.ppm'}
-
-    with TemporaryDirectory() as tmpdir, Image.open(input_file) as im:
-        if im.mode not in SUFFIXES.keys():
+    with Image.open(input_file) as im:
+        im_modified = False
+        if im.mode not in SUFFIXES:
            log.info("Converting image to other colorspace")
            try:
                if im.mode == 'P' and len(im.getcolors()) == 2:
@@ -52,11 +43,11 @@ def run(input_file, output_file, dpi, log, mode_args):
                else:
                    im = im.convert(mode='RGB')
            except IOError as e:
-                im.close()
                raise MissingDependencyError(
                    "Could not convert image with type " + im.mode
                ) from e
-
+            else:
+                im_modified = True
        try:
            suffix = SUFFIXES[im.mode]
        except KeyError:
@@ -64,9 +55,21 @@ def run(input_file, output_file, dpi, log, mode_args):
                "Failed to convert image to a supported format."
            ) from e

-        input_pnm = os.path.join(tmpdir, f'input{suffix}')
-        output_pnm = os.path.join(tmpdir, f'output{suffix}')
-        im.save(input_pnm, format='PPM')
+        if im_modified or input_file.suffix != '.png':
+            input_png = tmpdir / 'input.png'
+            im.save(input_png, format='PNG', compress_level=1)
+        else:
+            # No changes, PNG input, just use the file we already have
+            input_png = input_file
+        output_pnm = tmpdir / f'output{suffix}'
+    return input_png, output_pnm
+
+
+def run(input_file, output_file, dpi, mode_args):
+    args_unpaper = ['unpaper', '-v', '--dpi', str(dpi)] + mode_args
+
+    with TemporaryDirectory() as tmpdir:
+        input_png, output_pnm = _setup_unpaper_io(Path(tmpdir), input_file)

        # To prevent any shenanigans from accepting arbitrary parameters in
        # --unpaper-args, we:
@@ -75,23 +78,22 @@ def run(input_file, output_file, dpi, log, mode_args):
        # 3) append absolute paths for the input and output file
        # This should ensure that a user cannot clobber some other file with
        # their unpaper arguments (whether intentionally or otherwise)
-        args_unpaper.extend([input_pnm, output_pnm])
+        args_unpaper.extend([os.fspath(input_png), os.fspath(output_pnm)])
        try:
            proc = external_run(
                args_unpaper,
                check=True,
                close_fds=True,
                universal_newlines=True,
-                stderr=STDOUT,
-                cwd=tmpdir,
+                stderr=STDOUT,  # unpaper writes logging output to stdout and stderr
+                cwd=tmpdir,  # and cannot send file output to stdout
                stdout=PIPE,
            )
        except CalledProcessError as e:
-            log.debug(e.output)
+            log.debug(e.stderr)
            raise e from e
        else:
-            log.debug(proc.stdout)
-            # unpaper sets dpi to 72; fix this
+            log.debug(proc.stderr)
            try:
                with Image.open(output_pnm) as imout:
                    imout.save(output_file, dpi=(dpi, dpi))
@@ -110,7 +112,7 @@ def validate_custom_args(args: str):
    return unpaper_args


-def clean(input_file, output_file, dpi, log, unpaper_args=None):
+def clean(input_file, output_file, dpi, unpaper_args=None):
    default_args = [
        '--layout',
        'none',
@@ -124,4 +126,4 @@ def clean(input_file, output_file, dpi, log, unpaper_args=None):
    ]
    if not unpaper_args:
        unpaper_args = default_args
-    run(input_file, output_file, dpi, log, unpaper_args)
+    run(input_file, output_file, dpi, unpaper_args)
@@ -1,26 +1,18 @@
 # © 2018 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.

-import os
+
+import logging
 from contextlib import suppress
 from pathlib import Path
+from typing import Optional

 import pikepdf

+log = logging.getLogger(__name__)
 MAX_REPLACE_PAGES = 100


@@ -88,99 +80,10 @@ def strip_invisible_text(pdf, page):
    page.Contents = pikepdf.Stream(pdf, content_stream)


-def _graft_text_layer(
-    *, pdf_base, page_num, text, font, font_key, procset, rotation, strip_old_text, log
-):
-    """Insert the text layer from text page 0 on to pdf_base at page_num"""
-
-    log.debug("Grafting")
-    if Path(text).stat().st_size == 0:
-        return
-
-    # This is a pointer indicating a specific page in the base file
-    pdf_text = pikepdf.open(text)
-    pdf_text_contents = pdf_text.pages[0].Contents.read_bytes()
-
-    base_page = pdf_base.pages.p(page_num)
-
-    # The text page always will be oriented up by this stage but the original
-    # content may have a rotation applied. Wrap the text stream with a rotation
-    # so it will be oriented the same way as the rest of the page content.
-    # (Previous versions OCRmyPDF rotated the content layer to match the text.)
-    mediabox = [float(pdf_text.pages[0].MediaBox[v]) for v in range(4)]
-    wt, ht = mediabox[2] - mediabox[0], mediabox[3] - mediabox[1]
-
-    mediabox = [float(base_page.MediaBox[v]) for v in range(4)]
-    wp, hp = mediabox[2] - mediabox[0], mediabox[3] - mediabox[1]
-
-    translate = pikepdf.PdfMatrix().translated(-wt / 2, -ht / 2)
-    untranslate = pikepdf.PdfMatrix().translated(wp / 2, hp / 2)
-    corner = pikepdf.PdfMatrix().translated(mediabox[0], mediabox[1])
-    # -rotation because the input is a clockwise angle and this formula
-    # uses CCW
-    rotation = -rotation % 360
-    rotate = pikepdf.PdfMatrix().rotated(rotation)
-
-    # Because of rounding of DPI, we might get a text layer that is not
-    # identically sized to the target page. Scale to adjust. Normally this
-    # is within 0.998.
-    if rotation in (90, 270):
-        wt, ht = ht, wt
-    scale_x = wp / wt
-    scale_y = hp / ht
-
-    # log.debug('%r', scale_x, scale_y)
-    scale = pikepdf.PdfMatrix().scaled(scale_x, scale_y)
-
-    # Translate the text so it is centered at (0, 0), rotate it there, adjust
-    # for a size different between initial and text PDF, then untranslate, and
-    # finally move the lower left corner to match the mediabox
-    ctm = translate @ rotate @ scale @ untranslate @ corner
-
-    pdf_text_contents = b'q %s cm\n' % ctm.encode() + pdf_text_contents + b'\nQ\n'
-
-    new_text_layer = pikepdf.Stream(pdf_base, pdf_text_contents)
-
-    if strip_old_text:
-        strip_invisible_text(pdf_base, base_page)
-
-    base_page.page_contents_add(new_text_layer, prepend=True)
-
-    _update_page_resources(
-        page=base_page, font=font, font_key=font_key, procset=procset
-    )
-    pdf_text.close()
-
-
-def _find_font(text, pdf_base):
-    """Copy a font from the filename text into pdf_base"""
-
-    font, font_key = None, None
-    possible_font_names = ('/f-0-0', '/F1')
-    try:
-        with pikepdf.open(text) as pdf_text:
-            try:
-                pdf_text_fonts = pdf_text.pages[0].Resources.get('/Font', {})
-            except (AttributeError, IndexError, KeyError):
-                return None, None
-            for f in possible_font_names:
-                pdf_text_font = pdf_text_fonts.get(f, None)
-                if pdf_text_font is not None:
-                    font_key = f
-                    break
-            if pdf_text_font:
-                font = pdf_base.copy_foreign(pdf_text_font)
-            return font, font_key
-    except (FileNotFoundError, pikepdf.PdfError):
-        # PdfError occurs if a 0-length file is written e.g. due to OCR timeout
-        return None, None
-
-
 class OcrGrafter:
    def __init__(self, context):
        self.context = context
-        self.log = context.log
-        self.path_base = Path(context.origin).resolve()
+        self.path_base = context.origin

        self.pdf_base = pikepdf.open(self.path_base)
        self.font, self.font_key = None, None
@@ -195,10 +98,16 @@ class OcrGrafter:
        self.emplacements = 1
        self.interim_count = 0

-    def graft_page(self, page_result):
-        pageno, image, text, _sidecar, autorotate_correction = page_result
-        if text and not self.font:
-            self.font, self.font_key = _find_font(text, self.pdf_base)
+    def graft_page(
+        self,
+        *,
+        pageno: int,
+        image: Optional[Path],
+        textpdf: Optional[Path],
+        autorotate_correction: int,
+    ):
+        if textpdf and not self.font:
+            self.font, self.font_key = self._find_font(textpdf)

        emplaced_page = False
        content_rotation = self.pdfinfo[pageno].rotation
@@ -206,7 +115,7 @@ class OcrGrafter:
        if path_image is not None and path_image != self.path_base:
            # We are updating the old page with a rasterized PDF of the new
            # page (without changing objgen, to preserve references)
-            self.log.debug("Emplacement update")
+            log.debug("Emplacement update")
            with pikepdf.open(image) as pdf_image:
                self.emplacements += 1
                foreign_image_page = pdf_image.pages[0]
@@ -220,25 +129,23 @@ class OcrGrafter:
            content_rotation = autorotate_correction
        text_rotation = autorotate_correction
        text_misaligned = (text_rotation - content_rotation) % 360
-        self.log.debug(
+        log.debug(
            f"Rotations for page {pageno}: [text, auto, misalign, content] = "
            f"{text_rotation}, {autorotate_correction}, "
            f"{text_misaligned}, {content_rotation}"
        )

-        if text and self.font:
+        if textpdf and self.font:
            # Graft the text layer onto this page, whether new or old
            strip_old = self.context.options.redo_ocr
-            _graft_text_layer(
-                pdf_base=self.pdf_base,
+            self._graft_text_layer(
                page_num=pageno + 1,
-                text=text,
+                textpdf=textpdf,
                font=self.font,
                font_key=self.font_key,
                rotation=text_misaligned,
                procset=self.procset,
                strip_old_text=strip_old,
-                log=self.log,
            )

        # Correct the rotation if applicable
@@ -250,10 +157,13 @@ class OcrGrafter:
            self.save_and_reload()

    def save_and_reload(self):
-        # Periodically save and reload the Pdf object. This will keep a
-        # lid on our memory usage for very large files. Attach the font to
-        # page 1 even if page 1 doesn't use it, so we have a way to get it
-        # back.
+        """Save and reload the Pdf.
+
+        This will keep a lid on our memory usage for very large files. Attach
+        the font to page 1 even if page 1 doesn't use it, so we have a way to get it
+        back.
+        """
+
        page0 = self.pdf_base.pages[0]
        _update_page_resources(
            page=page0, font=self.font, font_key=self.font_key, procset=self.procset
@@ -264,12 +174,14 @@ class OcrGrafter:
        # {interim_count} is the opened file we were updateing
        # {interim_count - 1} can be deleted
        # {interim_count + 1} is the new file will produce and open
-        old_file = self.output_file + f'_working{self.interim_count - 1}.pdf'
+        old_file = self.output_file.with_suffix(f'.working{self.interim_count - 1}.pdf')
        if not self.context.options.keep_temporary_files:
            with suppress(FileNotFoundError):
-                os.unlink(old_file)
+                old_file.unlink()

-        next_file = self.output_file + f'_working{self.interim_count + 1}.pdf'
+        next_file = self.output_file.with_suffix(
+            f'.working{self.interim_count + 1}.pdf'
+        )
        self.pdf_base.save(next_file)
        self.pdf_base.close()

@@ -282,3 +194,98 @@ class OcrGrafter:
        self.pdf_base.save(self.output_file)
        self.pdf_base.close()
        return self.output_file
+
+    def _find_font(self, text):
+        """Copy a font from the filename text into pdf_base"""
+
+        font, font_key = None, None
+        possible_font_names = ('/f-0-0', '/F1')
+        try:
+            with pikepdf.open(text) as pdf_text:
+                try:
+                    pdf_text_fonts = pdf_text.pages[0].Resources.get('/Font', {})
+                except (AttributeError, IndexError, KeyError):
+                    return None, None
+                for f in possible_font_names:
+                    pdf_text_font = pdf_text_fonts.get(f, None)
+                    if pdf_text_font is not None:
+                        font_key = f
+                        break
+                if pdf_text_font:
+                    font = self.pdf_base.copy_foreign(pdf_text_font)
+                return font, font_key
+        except (FileNotFoundError, pikepdf.PdfError):
+            # PdfError occurs if a 0-length file is written e.g. due to OCR timeout
+            return None, None
+
+    def _graft_text_layer(
+        self,
+        *,
+        page_num: int,
+        textpdf: Path,
+        font: pikepdf.Object,
+        font_key: pikepdf.Object,
+        procset: pikepdf.Object,
+        rotation: int,
+        strip_old_text: bool,
+    ):
+        """Insert the text layer from text page 0 on to pdf_base at page_num"""
+
+        log.debug("Grafting")
+        if Path(textpdf).stat().st_size == 0:
+            return
+
+        # This is a pointer indicating a specific page in the base file
+        with pikepdf.open(textpdf) as pdf_text:
+            pdf_text_contents = pdf_text.pages[0].Contents.read_bytes()
+
+            base_page = self.pdf_base.pages.p(page_num)
+
+            # The text page always will be oriented up by this stage but the original
+            # content may have a rotation applied. Wrap the text stream with a rotation
+            # so it will be oriented the same way as the rest of the page content.
+            # (Previous versions OCRmyPDF rotated the content layer to match the text.)
+            mediabox = [float(pdf_text.pages[0].MediaBox[v]) for v in range(4)]
+            wt, ht = mediabox[2] - mediabox[0], mediabox[3] - mediabox[1]
+
+            mediabox = [float(base_page.MediaBox[v]) for v in range(4)]
+            wp, hp = mediabox[2] - mediabox[0], mediabox[3] - mediabox[1]
+
+            translate = pikepdf.PdfMatrix().translated(-wt / 2, -ht / 2)
+            untranslate = pikepdf.PdfMatrix().translated(wp / 2, hp / 2)
+            corner = pikepdf.PdfMatrix().translated(mediabox[0], mediabox[1])
+            # -rotation because the input is a clockwise angle and this formula
+            # uses CCW
+            rotation = -rotation % 360
+            rotate = pikepdf.PdfMatrix().rotated(rotation)
+
+            # Because of rounding of DPI, we might get a text layer that is not
+            # identically sized to the target page. Scale to adjust. Normally this
+            # is within 0.998.
+            if rotation in (90, 270):
+                wt, ht = ht, wt
+            scale_x = wp / wt
+            scale_y = hp / ht
+
+            # log.debug('%r', scale_x, scale_y)
+            scale = pikepdf.PdfMatrix().scaled(scale_x, scale_y)
+
+            # Translate the text so it is centered at (0, 0), rotate it there, adjust
+            # for a size different between initial and text PDF, then untranslate, and
+            # finally move the lower left corner to match the mediabox
+            ctm = translate @ rotate @ scale @ untranslate @ corner
+
+            pdf_text_contents = (
+                b'q %s cm\n' % ctm.encode() + pdf_text_contents + b'\nQ\n'
+            )
+
+            new_text_layer = pikepdf.Stream(self.pdf_base, pdf_text_contents)
+
+            if strip_old_text:
+                strip_invisible_text(self.pdf_base, base_page)
+
+            base_page.page_contents_add(new_text_layer, prepend=True)
+
+            _update_page_resources(
+                page=base_page, font=font, font_key=font_key, procset=procset
+            )
@@ -1,124 +1,79 @@
 # © 2018 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

-import logging
 import os
 import shutil
 import sys
+from argparse import Namespace
+from copy import copy
+from io import IOBase
+from pathlib import Path
+from typing import Iterator
+
+from ocrmypdf.pdfinfo import PdfInfo


-class PicklableLoggerMixin:
-    def __init__(self):
-        self._log = None
-
-    @property
-    def log(self):
-        if not self._log:
-            self._log = self.get_logger()
-        return self._log
-
-    def __getstate__(self):
-        # Python 3.6 is incapable of pickling a logger and marshalling it to another
-        # process (threading._RLock error), so we disconnect it before pickling,
-        # and create a new logger in the worker process.
-        state = self.__dict__.copy()
-        state['_log'] = None
-        return state
-
-
-class PDFContext(PicklableLoggerMixin):
+class PdfContext:
    """Holds our context for a particular run of the pipeline"""

-    def __init__(self, options, work_folder, origin, pdfinfo):
-        PicklableLoggerMixin.__init__(self)
+    def __init__(
+        self,
+        options: Namespace,
+        work_folder: Path,
+        origin: Path,
+        pdfinfo: PdfInfo,
+        plugin_manager,
+    ):
        self.options = options
        self.work_folder = work_folder
        self.origin = origin
        self.pdfinfo = pdfinfo
-        if options:
-            self.name = os.path.basename(options.input_file)
-        else:
-            self.name = 'origin.pdf'
-        if self.name == '-':
-            self.name = 'stdin'
+        self.plugin_manager = plugin_manager

-    def get_logger(self):
-        return make_logger(self.options, filename=self.name)
+    def get_path(self, name: str) -> Path:
+        return self.work_folder / name

-    def get_path(self, name):
-        return os.path.join(self.work_folder, name)
-
-    def get_page_contexts(self):
+    def get_page_contexts(self) -> Iterator['PageContext']:
        npages = len(self.pdfinfo)
        for n in range(npages):
            yield PageContext(self, n)


-class PageContext(PicklableLoggerMixin):
+class PageContext:
    """Holds our context for a page

-    Must be pickable, so only store intrinsic/simple data elements
+    Must be pickable, so stores only intrinsic/simple data elements or those
+    capable of their serializing themselves via __getstate__.
    """

-    def __init__(self, pdf_context, pageno):
-        PicklableLoggerMixin.__init__(self)
+    def __init__(self, pdf_context: PdfContext, pageno):
        self.work_folder = pdf_context.work_folder
        self.origin = pdf_context.origin
        self.options = pdf_context.options
-        self.name = pdf_context.name
        self.pageno = pageno
        self.pageinfo = pdf_context.pdfinfo[pageno]
-        self._log = None
+        self.plugin_manager = pdf_context.plugin_manager

-    def get_logger(self):
-        return make_logger(self.options, filename=self.name, page=self.pageno + 1)
+    def get_path(self, name: str) -> Path:
+        return self.work_folder / ("%06d_%s" % (self.pageno + 1, name))

-    def get_path(self, name):
-        return os.path.join(self.work_folder, "%06d_%s" % (self.pageno + 1, name))
+    def __getstate__(self):
+        state = self.__dict__.copy()
+
+        state['options'] = copy(self.options)
+        if not isinstance(state['options'].input_file, (str, bytes, os.PathLike)):
+            state['options'].input_file = 'stream'
+        if not isinstance(state['options'].output_file, (str, bytes, os.PathLike)):
+            state['options'].output_file = 'stream'
+        return state


-def cleanup_working_files(work_folder, options):
+def cleanup_working_files(work_folder: Path, options: Namespace):
    if options.keep_temporary_files:
        print(f"Temporary working files retained at:\n{work_folder}", file=sys.stderr)
    else:
        shutil.rmtree(work_folder, ignore_errors=True)
-
-
-class LogNameAdapter(logging.LoggerAdapter):
-    def process(self, msg, kwargs):
-        # return '[%s] %s' % (self.extra['input_filename'], msg), kwargs
-        return '%s' % (msg,), kwargs
-
-
-class LogNamePageAdapter(logging.LoggerAdapter):
-    def process(self, msg, kwargs):
-        return (
-            #'[%s:%05u] %s' % (self.extra['input_filename'], self.extra['page'], msg),
-            '%4u: %s' % (self.extra['page'], msg),
-            kwargs,
-        )
-
-
-def make_logger(options=None, prefix='ocrmypdf', filename=None, page=None):
-    log = logging.getLogger(prefix)
-    if filename and page:
-        adapter = LogNamePageAdapter(log, dict(input_filename=filename, page=page))
-    elif filename:
-        adapter = LogNameAdapter(log, dict(input_filename=filename))
-    else:
-        adapter = log
-    return adapter
@@ -0,0 +1,50 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+import logging
+import sys
+from contextlib import suppress
+
+from tqdm import tqdm
+
+
+class PageNumberFilter(logging.Filter):
+    def filter(self, record):
+        pageno = getattr(record, 'pageno', None)
+        if isinstance(pageno, int):
+            record.pageno = f'{pageno:5d} '
+        elif pageno is None:
+            record.pageno = ''
+        return True
+
+
+class TqdmConsole:
+    """Wrapper to log messages in a way that is compatible with tqdm progress bar
+
+    This routes log messages through tqdm so that it can print them above the
+    progress bar, and then refresh the progress bar, rather than overwriting
+    it which looks messy.
+
+    For some reason Python 3.6 prints extra empty messages from time to time,
+    so we suppress those.
+    """
+
+    def __init__(self, file):
+        self.file = file
+        self.py36 = sys.version_info[0:2] == (3, 6)
+
+    def write(self, msg):
+        # When no progress bar is active, tqdm.write() routes to print()
+        if self.py36:
+            if msg.strip() != '':
+                tqdm.write(msg.rstrip(), end='\n', file=self.file)
+        else:
+            tqdm.write(msg.rstrip(), end='\n', file=self.file)
+
+    def flush(self):
+        with suppress(AttributeError):
+            self.file.flush()
@@ -1,67 +1,63 @@
 # © 2016 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.

+
+import logging
 import os
 import re
 import sys
+from contextlib import suppress
 from datetime import datetime, timezone
 from pathlib import Path
 from shutil import copyfileobj
+from typing import BinaryIO, Dict, Iterable, Optional, Union, cast

 import img2pdf
 import pikepdf
 from pikepdf.models.metadata import encode_pdf_date
-from PIL import Image
+from PIL import Image, ImageColor, ImageDraw

-from . import leptonica
-from ._version import PROGRAM_NAME
-from ._version import __version__ as VERSION
-from .exceptions import (
+from ocrmypdf import leptonica
+from ocrmypdf._exec import unpaper
+from ocrmypdf._jobcontext import PageContext, PdfContext
+from ocrmypdf._version import PROGRAM_NAME
+from ocrmypdf._version import __version__ as VERSION
+from ocrmypdf.exceptions import (
    DpiError,
    EncryptedPdfError,
    InputFileError,
    PriorOcrFoundError,
    UnsupportedImageFormatError,
 )
-from .exec import ghostscript, tesseract
-from .helpers import safe_symlink
-from .hocrtransform import HocrTransform
-from .optimize import optimize
-from .pdfa import generate_pdfa_ps
-from .pdfinfo import Colorspace, Encoding, PdfInfo
+from ocrmypdf.helpers import Resolution, safe_symlink
+from ocrmypdf.hocrtransform import HocrTransform
+from ocrmypdf.optimize import optimize
+from ocrmypdf.pdfa import generate_pdfa_ps
+from ocrmypdf.pdfinfo import Colorspace, Encoding, PdfInfo
+
+log = logging.getLogger(__name__)

 VECTOR_PAGE_DPI = 400


-def triage_image_file(input_file, output_file, options, log):
+def triage_image_file(input_file, output_file, options):
    log.info("Input file is not a PDF, checking if it is an image...")
    try:
        im = Image.open(input_file)
    except EnvironmentError as e:
        # Recover the original filename
-        log.error(str(e).replace(input_file, options.input_file))
+        log.error(str(e).replace(str(input_file), str(options.input_file)))
        raise UnsupportedImageFormatError() from e

    with im:
        log.info("Input file is an image")
        if 'dpi' in im.info:
            if im.info['dpi'] <= (96, 96) and not options.image_dpi:
-                log.info("Image size: (%d, %d)" % im.size)
-                log.info("Image resolution: (%d, %d)" % im.info['dpi'])
+                log.info("Image size: (%d, %d)", *im.size)
+                log.info("Image resolution: (%d, %d)", *im.info['dpi'])
                log.error(
                    "Input file is an image, but the resolution (DPI) is "
                    "not credible.  Estimate the resolution at which the "
@@ -69,7 +65,7 @@ def triage_image_file(input_file, output_file, options, log):
                )
                raise DpiError()
        elif not options.image_dpi:
-            log.info("Image size: (%d, %d)" % im.size)
+            log.info("Image size: (%d, %d)", *im.size)
            log.error(
                "Input file is an image, but has no resolution (DPI) "
                "in its metadata.  Estimate the resolution at which "
@@ -96,11 +92,14 @@ def triage_image_file(input_file, output_file, options, log):
        layout_fun = img2pdf.default_layout_fun
        if options.image_dpi:
            layout_fun = img2pdf.get_fixed_dpi_layout_fun(
-                (options.image_dpi, options.image_dpi)
+                Resolution(options.image_dpi, options.image_dpi)
            )
        with open(output_file, 'wb') as outf:
            img2pdf.convert(
-                input_file, layout_fun=layout_fun, with_pdfrw=False, outputstream=outf
+                os.fspath(input_file),
+                layout_fun=layout_fun,
+                with_pdfrw=False,
+                outputstream=outf,
            )
        log.info("Successfully converted to PDF, processing...")
    except img2pdf.ImageOpenError as e:
@@ -124,7 +123,7 @@ def _pdf_guess_version(input_file, search_window=1024):
    return ''


-def triage(original_filename, input_file, output_file, options, log):
+def triage(original_filename, input_file, output_file, options):
    try:
        if _pdf_guess_version(input_file):
            if options.image_dpi:
@@ -137,17 +136,27 @@ def triage(original_filename, input_file, output_file, options, log):
            return output_file
    except EnvironmentError as e:
        log.debug(f"Temporary file was at: {input_file}")
-        msg = str(e).replace(input_file, original_filename)
+        msg = str(e).replace(str(input_file), original_filename)
        raise InputFileError(msg) from e

-    triage_image_file(input_file, output_file, options, log)
+    triage_image_file(input_file, output_file, options)
    return output_file


-def get_pdfinfo(input_file, detailed_page_analysis=False, progbar=False):
+def get_pdfinfo(
+    input_file,
+    detailed_analysis=False,
+    progbar=False,
+    max_workers=None,
+    check_pages=None,
+):
    try:
        return PdfInfo(
-            input_file, detailed_page_analysis=detailed_page_analysis, progbar=progbar
+            input_file,
+            detailed_analysis=detailed_analysis,
+            progbar=progbar,
+            max_workers=max_workers,
+            check_pages=check_pages,
        )
    except pikepdf.PasswordError:
        raise EncryptedPdfError()
@@ -155,8 +164,7 @@ def get_pdfinfo(input_file, detailed_page_analysis=False, progbar=False):
        raise InputFileError()


-def validate_pdfinfo_options(context):
-    log = context.log
+def validate_pdfinfo_options(context: PdfContext):
    pdfinfo = context.pdfinfo
    options = context.options

@@ -194,54 +202,56 @@ def validate_pdfinfo_options(context):
                    "form and all filled form fields. The output PDF will be "
                    "'flattened' and will no longer be fillable."
                )
+    context.plugin_manager.hook.validate(pdfinfo=pdfinfo, options=options)


 def get_page_dpi(pageinfo, options):
    "Get the DPI when nonsquare DPI is tolerable"
    xres = max(
-        pageinfo.xres or VECTOR_PAGE_DPI,
-        options.oversample or 0,
-        VECTOR_PAGE_DPI if pageinfo.has_vector else 0,
+        pageinfo.dpi.x or VECTOR_PAGE_DPI,
+        options.oversample or 0.0,
+        VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
    )
    yres = max(
-        pageinfo.yres or VECTOR_PAGE_DPI,
+        pageinfo.dpi.y or VECTOR_PAGE_DPI,
        options.oversample or 0,
-        VECTOR_PAGE_DPI if pageinfo.has_vector else 0,
+        VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
    )
-    return (float(xres), float(yres))
+    return Resolution(float(xres), float(yres))


-def get_page_square_dpi(pageinfo, options):
+def get_page_square_dpi(pageinfo, options) -> Resolution:
    "Get the DPI when we require xres == yres, scaled to physical units"
-    xres = pageinfo.xres or 0
-    yres = pageinfo.yres or 0
-    userunit = pageinfo.userunit or 1
-    return float(
+    xres = pageinfo.dpi.x or 0.0
+    yres = pageinfo.dpi.y or 0.0
+    userunit = float(pageinfo.userunit) or 1.0
+    units = float(
        max(
            (xres * userunit) or VECTOR_PAGE_DPI,
            (yres * userunit) or VECTOR_PAGE_DPI,
-            VECTOR_PAGE_DPI if pageinfo.has_vector else 0,
-            options.oversample or 0,
+            VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
+            options.oversample or 0.0,
        )
    )
+    return Resolution(units, units)


-def get_canvas_square_dpi(pageinfo, options):
+def get_canvas_square_dpi(pageinfo, options) -> Resolution:
    """Get the DPI when we require xres == yres, in Postscript units"""
-    return float(
+    units = float(
        max(
-            (pageinfo.xres) or VECTOR_PAGE_DPI,
-            (pageinfo.yres) or VECTOR_PAGE_DPI,
-            VECTOR_PAGE_DPI if pageinfo.has_vector else 0,
-            options.oversample or 0,
+            (pageinfo.dpi.x) or VECTOR_PAGE_DPI,
+            (pageinfo.dpi.y) or VECTOR_PAGE_DPI,
+            VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
+            options.oversample or 0.0,
        )
    )
+    return Resolution(units, units)


-def is_ocr_required(page_context):
+def is_ocr_required(page_context: PageContext):
    pageinfo = page_context.pageinfo
    options = page_context.options
-    log = page_context.log

    ocr_required = True

@@ -251,14 +261,15 @@ def is_ocr_required(page_context):
    elif pageinfo.has_text:
        if not options.force_ocr and not (options.skip_text or options.redo_ocr):
            raise PriorOcrFoundError(
-                "page already has text! - aborting (use --force-ocr to force OCR)"
+                "page already has text! - aborting (use --force-ocr to force OCR; "
+                " see also help for the arguments --skip-text and --redo-ocr"
            )
        elif options.force_ocr:
            log.info("page already has text! - rasterizing text and running OCR anyway")
            ocr_required = True
        elif options.redo_ocr:
            if pageinfo.has_corrupt_text:
-                log.warn(
+                log.warning(
                    "some text on this page cannot be mapped to characters: "
                    "consider using --force-ocr instead"
                )
@@ -285,7 +296,7 @@ def is_ocr_required(page_context):
            )
        elif options.force_ocr:
            # Warn the user they might not want to do this
-            log.warn(
+            log.warning(
                "page has no images - "
                "all vector content will be "
                f"rasterized at {VECTOR_PAGE_DPI} DPI, losing some resolution and likely "
@@ -305,31 +316,29 @@ def is_ocr_required(page_context):
        pixel_count = pageinfo.width_pixels * pageinfo.height_pixels
        if pixel_count > (options.skip_big * 1_000_000):
            ocr_required = False
-            log.warn(
+            log.warning(
                "page too big, skipping OCR "
                f"({(pixel_count / 1_000_000):.1f} MPixels > {options.skip_big:.1f} MPixels --skip-big)"
            )
    return ocr_required


-def rasterize_preview(input_file, page_context):
+def rasterize_preview(input_file: Path, page_context: PageContext):
    output_file = page_context.get_path('rasterize_preview.jpg')
    canvas_dpi = get_canvas_square_dpi(page_context.pageinfo, page_context.options)
    page_dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)
-    ghostscript.rasterize_pdf(
-        input_file,
-        output_file,
-        xres=canvas_dpi,
-        yres=canvas_dpi,
+    page_context.plugin_manager.hook.rasterize_pdf_page(
+        input_file=input_file,
+        output_file=output_file,
        raster_device='jpeggray',
-        log=page_context.log,
-        page_dpi=(page_dpi, page_dpi),
+        raster_dpi=canvas_dpi,
+        page_dpi=page_dpi,
        pageno=page_context.pageinfo.pageno + 1,
    )
    return output_file


-def describe_rotation(page_context, orient_conf, correction):
+def describe_rotation(page_context: PageContext, orient_conf, correction: int):
    """
    Describe the page rotation we are going to perform.
    """
@@ -358,34 +367,28 @@ def describe_rotation(page_context, orient_conf, correction):
    return f"{facing}, confidence {orient_conf.confidence:.2f} - {action}"


-def get_orientation_correction(preview, page_context):
-    """
-    Work out orientation correct for each page.
+def get_orientation_correction(preview: Path, page_context: PageContext):
+    """Work out orientation correct for each page.

    We ask Ghostscript to draw a preview page, which will rasterize with the
-    current /Rotate applied, and then ask Tesseract which way the page is
+    current /Rotate applied, and then ask OCR which way the page is
    oriented. If the value of /Rotate is correct (e.g., a user already
-    manually fixed rotation), then Tesseract will say the page is pointing
+    manually fixed rotation), then OCR will say the page is pointing
    up and the correction is zero. Otherwise, the orientation found by
-    Tesseract represents the clockwise rotation, or the counterclockwise
+    OCR represents the clockwise rotation, or the counterclockwise
    correction to rotation.

    When we draw the real page for OCR, we rotate it by the CCW correction,
    which points it (hopefully) upright. _graft.py takes care of the orienting
    the image and text layers.
-
    """

-    orient_conf = tesseract.get_orientation(
-        preview,
-        engine_mode=page_context.options.tesseract_oem,
-        timeout=page_context.options.tesseract_timeout,
-        log=page_context.log,
-        tesseract_env=page_context.options.tesseract_env,
+    orient_conf = page_context.plugin_manager.hook.get_ocr_engine().get_orientation(
+        preview, page_context.options
    )

    correction = orient_conf.angle % 360
-    page_context.log.info(describe_rotation(page_context, orient_conf, correction))
+    log.info(describe_rotation(page_context, orient_conf, correction))
    if (
        orient_conf.confidence >= page_context.options.rotate_pages_threshold
        and correction != 0
@@ -396,7 +399,11 @@ def get_orientation_correction(preview, page_context):


 def rasterize(
-    input_file, page_context, correction=0, output_tag='', remove_vectors=None
+    input_file: Path,
+    page_context: PageContext,
+    correction: int = 0,
+    output_tag: str = '',
+    remove_vectors=None,
 ):
    colorspaces = ['pngmono', 'pnggray', 'png256', 'png16m']
    device_idx = 0
@@ -426,21 +433,19 @@ def rasterize(

    device = colorspaces[device_idx]

-    page_context.log.debug(f"Rasterize with {device}")
+    log.debug(f"Rasterize with {device}")

    # Produce the page image with square resolution or else deskew and OCR
    # will not work properly.
    canvas_dpi = get_canvas_square_dpi(pageinfo, page_context.options)
    page_dpi = get_page_square_dpi(pageinfo, page_context.options)

-    ghostscript.rasterize_pdf(
-        input_file,
-        output_file,
-        xres=canvas_dpi,
-        yres=canvas_dpi,
+    page_context.plugin_manager.hook.rasterize_pdf_page(
+        input_file=input_file,
+        output_file=output_file,
        raster_device=device,
-        log=page_context.log,
-        page_dpi=(page_dpi, page_dpi),
+        raster_dpi=canvas_dpi,
+        page_dpi=page_dpi,
        pageno=pageinfo.pageno + 1,
        rotation=correction,
        filter_vector=remove_vectors,
@@ -448,39 +453,31 @@ def rasterize(
    return output_file


-def preprocess_remove_background(input_file, page_context):
+def preprocess_remove_background(input_file: Path, page_context: PageContext):
    if any(image.bpc > 1 for image in page_context.pageinfo.images):
        output_file = page_context.get_path('pp_rm_bg.png')
        leptonica.remove_background(input_file, output_file)
        return output_file
    else:
-        page_context.log.info("background removal skipped on mono page")
+        log.info("background removal skipped on mono page")
        return input_file


-def preprocess_deskew(input_file, page_context):
+def preprocess_deskew(input_file: Path, page_context: PageContext):
    output_file = page_context.get_path('pp_deskew.png')
    dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)
-    leptonica.deskew(input_file, output_file, dpi)
+    leptonica.deskew(input_file, output_file, dpi.x)
    return output_file


-def preprocess_clean(input_file, page_context):
-    from .exec import unpaper
-
+def preprocess_clean(input_file: Path, page_context: PageContext):
    output_file = page_context.get_path('pp_clean.png')
    dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)
-    unpaper.clean(
-        input_file,
-        output_file,
-        dpi,
-        page_context.log,
-        page_context.options.unpaper_args,
-    )
+    unpaper.clean(input_file, output_file, dpi.x, page_context.options.unpaper_args)
    return output_file


-def create_ocr_image(image, page_context):
+def create_ocr_image(image: Path, page_context: PageContext):
    """Create the image we send for OCR. May not be the same as the display
    image depending on preprocessing. This image will never be shown to the
    user."""
@@ -488,15 +485,11 @@ def create_ocr_image(image, page_context):
    output_file = page_context.get_path('ocr.png')
    options = page_context.options
    with Image.open(image) as im:
-        from PIL import ImageColor
-        from PIL import ImageDraw
-
        white = ImageColor.getcolor('#ffffff', im.mode)
        # pink = ImageColor.getcolor('#ff0080', im.mode)
        draw = ImageDraw.ImageDraw(im)

-        xres, yres = im.info['dpi']
-        page_context.log.debug('resolution %r %r' % (xres, yres))
+        log.debug('resolution %r', im.info['dpi'])

        if not options.force_ocr:
            # Do not mask text areas when forcing OCR, because we need to OCR
@@ -512,46 +505,50 @@ def create_ocr_image(image, page_context):
                # without regard whatever resolution is in pageinfo (may differ or
                # be None)
                bbox = [float(v) for v in textarea]
-                xscale, yscale = float(xres) / 72.0, float(yres) / 72.0
+                xyscale = tuple(float(coord) / 72.0 for coord in im.info['dpi'])
                pixcoords = [
-                    bbox[0] * xscale,
-                    im.height - bbox[3] * yscale,
-                    bbox[2] * xscale,
-                    im.height - bbox[1] * yscale,
+                    bbox[0] * xyscale[0],
+                    im.height - bbox[3] * xyscale[1],
+                    bbox[2] * xyscale[0],
+                    im.height - bbox[1] * xyscale[1],
                ]
                pixcoords = [int(round(c)) for c in pixcoords]
-                page_context.log.debug('blanking %r', pixcoords)
+                log.debug('blanking %r', pixcoords)
                draw.rectangle(pixcoords, fill=white)
                # draw.rectangle(pixcoords, outline=pink)

        if options.threshold:
            pix = leptonica.Pix.frompil(im)
            pix = pix.masked_threshold_on_background_norm()
-            im = pix.topil()
+            im_pix = pix.topil()
+            im_pix.info['dpi'] = im.info['dpi']
+            im = im_pix

        del draw
+
+        filter_im = page_context.plugin_manager.hook.filter_ocr_image(
+            page=page_context, image=im
+        )
+        if filter_im is not None:
+            im = filter_im
+
        # Pillow requires integer DPI
-        dpi = round(xres), round(yres)
+        dpi = tuple(round(coord) for coord in im.info['dpi'])
        im.save(output_file, dpi=dpi)
    return output_file


-def ocr_tesseract_hocr(input_file, page_context):
+def ocr_engine_hocr(input_file: Path, page_context: PageContext):
    hocr_out = page_context.get_path('ocr_hocr.hocr')
    hocr_text_out = page_context.get_path('ocr_hocr.txt')
    options = page_context.options
-    tesseract.generate_hocr(
+
+    ocr_engine = page_context.plugin_manager.hook.get_ocr_engine()
+    ocr_engine.generate_hocr(
        input_file=input_file,
-        output_files=[hocr_out, hocr_text_out],
-        language=options.language,
-        engine_mode=options.tesseract_oem,
-        tessconfig=options.tesseract_config,
-        timeout=options.tesseract_timeout,
-        pagesegmode=options.tesseract_pagesegmode,
-        user_words=options.user_words,
-        user_patterns=options.user_patterns,
-        tesseract_env=options.tesseract_env,
-        log=page_context.log,
+        output_hocr=hocr_out,
+        output_text=hocr_text_out,
+        options=options,
    )
    return (hocr_out, hocr_text_out)

@@ -561,24 +558,26 @@ def should_visible_page_image_use_jpg(pageinfo):
    return pageinfo.images and all(im.enc == Encoding.jpeg for im in pageinfo.images)


-def create_visible_page_jpg(image, page_context):
+def create_visible_page_jpg(image: Path, page_context: PageContext) -> Path:
    output_file = page_context.get_path('visible.jpg')
    with Image.open(image) as im:
        # At this point the image should be a .png, but deskew, unpaper
        # might have removed the DPI information. In this case, fall back to
        # square DPI used to rasterize. When the preview image was
        # rasterized, it was also converted to square resolution, which is
-        # what we want to give tesseract, so keep it square.
-        fallback_dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)
-        dpi = im.info.get('dpi', (fallback_dpi, fallback_dpi))
+        # what we want to give to the OCR engine, so keep it square.
+        if 'dpi' in im.info:
+            dpi = Resolution(*im.info['dpi'])
+        else:
+            # Fallback to page-implied DPI
+            dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)

        # Pillow requires integer DPI
-        dpi = round(dpi[0]), round(dpi[1])
-        im.save(output_file, format='JPEG', dpi=dpi)
+        im.save(output_file, format='JPEG', dpi=dpi.to_int())
    return output_file


-def create_pdf_page_from_image(image, page_context):
+def create_pdf_page_from_image(image: Path, page_context: PageContext):
    # We rasterize a square DPI version of each page because most image
    # processing tools don't support rectangular DPI. Use the square DPI as it
    # accurately describes the image. It would be possible to resample the image
@@ -587,56 +586,50 @@ def create_pdf_page_from_image(image, page_context):
    # sandwich renderer would be fine.
    output_file = page_context.get_path('visible.pdf')
    dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)
-    layout_fun = img2pdf.get_fixed_dpi_layout_fun((dpi, dpi))
+    layout_fun = img2pdf.get_fixed_dpi_layout_fun(dpi)

    # This create a single page PDF
    with open(image, 'rb') as imfile, open(output_file, 'wb') as pdf:
-        page_context.log.debug('convert')
+        log.debug('convert')
        img2pdf.convert(
            imfile, with_pdfrw=False, layout_fun=layout_fun, outputstream=pdf
        )
-        page_context.log.debug('convert done')
+        log.debug('convert done')
    return output_file


-def render_hocr_page(hocr, page_context):
+def render_hocr_page(hocr: Path, page_context: PageContext):
    output_file = page_context.get_path('ocr_hocr.pdf')
    dpi = get_page_square_dpi(page_context.pageinfo, page_context.options)
-    hocrtransform = HocrTransform(hocr, dpi)
+    hocrtransform = HocrTransform(hocr, dpi.x)  # square
    hocrtransform.to_pdf(
        output_file,
-        imageFileName=None,
-        showBoundingboxes=False,
-        invisibleText=True,
-        interwordSpaces=True,
+        image_filename=None,
+        show_bounding_boxes=False,
+        invisible_text=True,
+        interword_spaces=True,
    )
    return output_file


-def ocr_tesseract_textonly_pdf(input_image, page_context):
+def ocr_engine_textonly_pdf(input_image: Path, page_context: PageContext):
    output_pdf = page_context.get_path('ocr_tess.pdf')
    output_text = page_context.get_path('ocr_tess.txt')
    options = page_context.options
-    tesseract.generate_pdf(
-        input_image=input_image,
-        skip_pdf=None,
+
+    ocr_engine = page_context.plugin_manager.hook.get_ocr_engine()
+    ocr_engine.generate_pdf(
+        input_file=input_image,
        output_pdf=output_pdf,
        output_text=output_text,
-        language=options.language,
-        engine_mode=options.tesseract_oem,
-        text_only=True,
-        tessconfig=options.tesseract_config,
-        timeout=options.tesseract_timeout,
-        pagesegmode=options.tesseract_pagesegmode,
-        user_words=options.user_words,
-        user_patterns=options.user_patterns,
-        tesseract_env=options.tesseract_env,
-        log=page_context.log,
+        options=options,
    )
    return (output_pdf, output_text)


-def get_docinfo(base_pdf, options):
+def get_docinfo(base_pdf: pikepdf.Pdf, context: PdfContext) -> Dict[str, str]:
+    options = context.options
+
    def from_document_info(key):
        try:
            s = base_pdf.docinfo[key]
@@ -648,7 +641,6 @@ def get_docinfo(base_pdf, options):
        k: from_document_info(k)
        for k in ('/Title', '/Author', '/Keywords', '/Subject', '/CreationDate')
    }
-    renderer_tag = 'OCR'
    if options is not None:
        if options.title:
            pdfmark['/Title'] = options.title
@@ -659,12 +651,9 @@ def get_docinfo(base_pdf, options):
        if options.subject:
            pdfmark['/Subject'] = options.subject

-        if options.pdf_renderer == 'sandwich':
-            renderer_tag = 'OCR-PDF'
+    creator_tag = context.plugin_manager.hook.get_ocr_engine().creator_tag(options)

-    pdfmark['/Creator'] = (
-        f'{PROGRAM_NAME} {VERSION} / ' f'Tesseract {renderer_tag} {tesseract.version()}'
-    )
+    pdfmark['/Creator'] = f'{PROGRAM_NAME} {VERSION} / {creator_tag}'
    pdfmark['/Producer'] = f'pikepdf {pikepdf.__version__}'
    if 'OCRMYPDF_CREATOR' in os.environ:
        pdfmark['/Creator'] = os.environ['OCRMYPDF_CREATOR']
@@ -675,13 +664,13 @@ def get_docinfo(base_pdf, options):
    return pdfmark


-def generate_postscript_stub(context):
+def generate_postscript_stub(context: PdfContext):
    output_file = context.get_path('pdfa.ps')
    generate_pdfa_ps(output_file)
    return output_file


-def convert_to_pdfa(input_pdf, input_ps_stub, context):
+def convert_to_pdfa(input_pdf: Path, input_ps_stub: Path, context: PdfContext):
    options = context.options
    input_pdfinfo = context.pdfinfo
    fix_docinfo_file = context.get_path('fix_docinfo.pdf')
@@ -697,7 +686,7 @@ def convert_to_pdfa(input_pdf, input_ps_stub, context):
        try:
            len(pdf_file.docinfo)
        except TypeError:
-            context.log.error(
+            log.error(
                "File contains a malformed DocumentInfo block - continuing anyway"
            )
        else:
@@ -711,26 +700,26 @@ def convert_to_pdfa(input_pdf, input_ps_stub, context):
        else:
            safe_symlink(input_pdf, fix_docinfo_file)

-    ghostscript.generate_pdfa(
+    context.plugin_manager.hook.generate_pdfa(
        pdf_version=input_pdfinfo.min_version,
-        pdf_pages=[fix_docinfo_file, input_ps_stub],
+        pdf_pages=[fix_docinfo_file],
+        pdfmark=input_ps_stub,
        output_file=output_file,
        compression=options.pdfa_image_compression,
-        log=context.log,
        pdfa_part=options.output_type[-1],  # is pdfa-1, pdfa-2, or pdfa-3
    )

    return output_file


-def should_linearize(working_file, context):
+def should_linearize(working_file: Path, context: PdfContext):
    filesize = os.stat(working_file).st_size
    if filesize > (context.options.fast_web_view * 1_000_000):
        return True
    return False


-def metadata_fixup(working_file, context):
+def metadata_fixup(working_file: Path, context: PdfContext):
    output_file = context.get_path('metafix.pdf')
    options = context.options

@@ -738,25 +727,21 @@ def metadata_fixup(working_file, context):
        if not missing:
            return
        if options.output_type.startswith('pdfa'):
-            context.log.warning(
+            log.warning(
                "Some input metadata could not be copied because it is not "
                "permitted in PDF/A. You may wish to examine the output "
                "PDF's XMP metadata."
            )
-            context.log.debug(
-                "The following metadata fields were not copied: %r", missing
-            )
+            log.debug("The following metadata fields were not copied: %r", missing)
        else:
-            context.log.error(
+            log.error(
                "Some input metadata could not be copied."
                "You may wish to examine the output PDF's XMP metadata."
            )
-            context.log.info(
-                "The following metadata fields were not copied: %r", missing
-            )
+            log.info("The following metadata fields were not copied: %r", missing)

    with pikepdf.open(context.origin) as original, pikepdf.open(working_file) as pdf:
-        docinfo = get_docinfo(original, options)
+        docinfo = get_docinfo(original, context)
        with pdf.open_metadata() as meta:
            meta.load_from_docinfo(docinfo, delete_missing=False, raise_failure=False)
            # If xmp:CreateDate is missing, set it to the modify date to
@@ -764,6 +749,14 @@ def metadata_fixup(working_file, context):
            if 'xmp:CreateDate' not in meta:
                meta['xmp:CreateDate'] = meta.get('xmp:ModifyDate', '')

+            # Ghostscript likes to set title to Untitled if omitted from input.
+            # Reverse this, because PDF/A TechNote 0003:Metadata in PDF/A-1
+            # and the XMP Spec do not make this recommendation.
+            if meta.get('dc:title') == 'Untitled':
+                with original.open_metadata() as original_meta:
+                    if 'dc:title' not in original_meta:
+                        del meta['dc:title']
+
            meta_original = original.open_metadata()
            missing = set(meta_original.keys()) - set(meta.keys())
            report_on_metadata(missing)
@@ -783,7 +776,7 @@ def metadata_fixup(working_file, context):
    return output_file


-def optimize_pdf(input_file, context):
+def optimize_pdf(input_file: Path, context: PdfContext):
    output_file = context.get_path('optimize.pdf')
    save_settings = dict(
        compress_streams=True,
@@ -795,7 +788,7 @@ def optimize_pdf(input_file, context):
    return output_file


-def merge_sidecars(txt_files, context):
+def merge_sidecars(txt_files: Iterable[Optional[Path]], context: PdfContext):
    output_file = context.get_path('sidecar.txt')
    with open(output_file, 'w', encoding="utf-8") as stream:
        for page_num, txt_file in enumerate(txt_files):
@@ -804,11 +797,9 @@ def merge_sidecars(txt_files, context):
            if txt_file:
                with open(txt_file, 'r', encoding="utf-8") as in_:
                    txt = in_.read()
-                    # Tesseract v4 alpha started adding form feeds in
-                    # commit aa6eb6b
-                    # No obvious way to detect what binaries will do this, so
-                    # for consistency just ignore its form feeds and insert our
-                    # own
+                    # Some OCR engines (e.g. Tesseract v4 alpha) add form feeds
+                    # between pages, and some do not. For consistency, we ignore
+                    # any added by the OCR engine and them on our own.
                    if txt.endswith('\f'):
                        stream.write(txt[:-1])
                    else:
@@ -818,12 +809,17 @@ def merge_sidecars(txt_files, context):
    return output_file


-def copy_final(input_file, output_file, context):
-    context.log.debug('%s -> %s', input_file, output_file)
+def copy_final(input_file, output_file, _context: PdfContext):
+    log.debug('%s -> %s', input_file, output_file)
    with open(input_file, 'rb') as input_stream:
        if output_file == '-':
            copyfileobj(input_stream, sys.stdout.buffer)
            sys.stdout.flush()
+        elif hasattr(output_file, 'writable'):
+            output_stream = output_file
+            copyfileobj(input_stream, output_stream)
+            with suppress(AttributeError):
+                output_stream.flush()
        else:
            # At this point we overwrite the output_file specified by the user
            # use copyfileobj because then we use open() to create the file and
@@ -0,0 +1,103 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+import argparse
+import importlib
+import importlib.util
+import sys
+from functools import partial
+from pathlib import Path
+from typing import Callable, List, Tuple, Union
+
+import pluggy
+
+from ocrmypdf import pluginspec
+from ocrmypdf.cli import get_parser, plugins_only_parser
+
+
+class OcrmypdfPluginManager(pluggy.PluginManager):
+    """pluggy.PluginManager that can fork.
+
+    Capable of reconstructing itself in child workers.
+
+    Arguments:
+        setup_func: callback that initializes the plugin manager with all
+            standard plugins
+    """
+
+    def __init__(
+        self, *args, setup_func: Callable[[pluggy.PluginManager], None], **kwargs
+    ):
+        self._init_args = args
+        self._setup_func = setup_func
+        self._init_kwargs = kwargs
+        super().__init__(*args, **kwargs)
+        setup_func(self)
+
+    def __getstate__(self):
+        state = dict(
+            _init_args=self._init_args,
+            _setup_func=self._setup_func,
+            _init_kwargs=self._init_kwargs,
+        )
+        return state
+
+    def __setstate__(self, state):
+        self.__init__(
+            *state['_init_args'],
+            setup_func=state['_setup_func'],
+            **state['_init_kwargs'],
+        )
+
+
+def _setup_plugins(
+    pm: pluggy.PluginManager, plugins: List[Union[str, Path]], builtins: bool = True
+):
+    pm.add_hookspecs(pluginspec)
+
+    all_plugins: List[Union[str, Path]] = []
+    if builtins:
+        all_plugins.extend(
+            [
+                'ocrmypdf.builtin_plugins.ghostscript',
+                'ocrmypdf.builtin_plugins.tesseract_ocr',
+            ]
+        )
+    all_plugins.extend(plugins)
+    for name in all_plugins:
+        if isinstance(name, Path) or name.endswith('.py'):
+            # Import by filename
+            module_name = Path(name).stem
+            spec = importlib.util.spec_from_file_location(module_name, name)
+            module = importlib.util.module_from_spec(spec)
+            sys.modules[module_name] = module
+            spec.loader.exec_module(module)
+        else:
+            # Import by dotted module name
+            module = importlib.import_module(name)
+        pm.register(module)
+
+
+def get_plugin_manager(plugins: List[str], builtins=True):
+    pm = OcrmypdfPluginManager(
+        project_name='ocrmypdf',
+        setup_func=partial(_setup_plugins, plugins=plugins, builtins=builtins),
+    )
+    return pm
+
+
+def get_parser_options_plugins(
+    args,
+) -> Tuple[argparse.ArgumentParser, argparse.Namespace, pluggy.PluginManager]:
+    pre_options, _unused = plugins_only_parser.parse_known_args(args=args)
+    plugin_manager = get_plugin_manager(pre_options.plugins)
+
+    parser = get_parser()
+    plugin_manager.hook.add_options(parser=parser)  # pylint: disable=no-member
+
+    options = parser.parse_args(args=args)
+    return parser, options, plugin_manager
@@ -1,37 +1,28 @@
 # © 2016 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import logging
 import logging.handlers
-import multiprocessing
 import os
-import signal
 import sys
 import threading
-from collections import namedtuple
+from functools import partial
 from pathlib import Path
 from tempfile import mkdtemp
+from typing import List, NamedTuple, Optional, Tuple

+import pikepdf
 import PIL
-from tqdm import tqdm

-from ._graft import OcrGrafter
-from ._jobcontext import PDFContext, cleanup_working_files, make_logger
-from ._pipeline import (
+from ocrmypdf._concurrent import exec_progress_pool
+from ocrmypdf._graft import OcrGrafter
+from ocrmypdf._jobcontext import PageContext, PdfContext, cleanup_working_files
+from ocrmypdf._logging import PageNumberFilter
+from ocrmypdf._pipeline import (
    convert_to_pdfa,
    copy_final,
    create_ocr_image,
@@ -43,8 +34,8 @@ from ._pipeline import (
    is_ocr_required,
    merge_sidecars,
    metadata_fixup,
-    ocr_tesseract_hocr,
-    ocr_tesseract_textonly_pdf,
+    ocr_engine_hocr,
+    ocr_engine_textonly_pdf,
    optimize_pdf,
    preprocess_clean,
    preprocess_deskew,
@@ -56,22 +47,56 @@ from ._pipeline import (
    triage,
    validate_pdfinfo_options,
 )
-from ._validation import (
+from ocrmypdf._plugin_manager import get_plugin_manager
+from ocrmypdf._validation import (
    check_requested_output_file,
    create_input_file,
    report_output_file_size,
 )
-from .exceptions import ExitCode, ExitCodeException
-from .exec import qpdf
-from .helpers import available_cpu_count
-from .pdfa import file_claims_pdfa
-
-PageResult = namedtuple(
-    'PageResult', 'pageno, pdf_page_from_image, ocr, text, orientation_correction'
+from ocrmypdf.exceptions import ExitCode, ExitCodeException
+from ocrmypdf.helpers import (
+    available_cpu_count,
+    check_pdf,
+    pikepdf_enable_mmap,
+    samefile,
 )
+from ocrmypdf.pdfa import file_claims_pdfa
+
+log = logging.getLogger(__name__)


-def preprocess(page_context, image, remove_background, deskew, clean):
+class PageResult(NamedTuple):
+    pageno: int
+    pdf_page_from_image: Optional[Path]
+    ocr: Optional[Path]
+    text: Optional[Path]
+    orientation_correction: int
+
+
+tls = threading.local()
+tls.pageno = None
+
+
+old_factory = logging.getLogRecordFactory()
+
+
+def record_factory(*args, **kwargs):
+    record = old_factory(*args, **kwargs)
+    if hasattr(tls, 'pageno'):
+        record.pageno = tls.pageno
+    return record
+
+
+logging.setLogRecordFactory(record_factory)
+
+
+def preprocess(
+    page_context: PageContext,
+    image: Path,
+    remove_background: bool,
+    deskew: bool,
+    clean: bool,
+) -> Path:
    if remove_background:
        image = preprocess_remove_background(image, page_context)
    if deskew:
@@ -81,54 +106,55 @@ def preprocess(page_context, image, remove_background, deskew, clean):
    return image


-def exec_page_sync(page_context):
+def make_intermediate_images(
+    page_context: PageContext, orientation_correction: int
+) -> Tuple[Path, Optional[Path]]:
    options = page_context.options
-    orientation_correction = 0
-    pdf_page_from_image_out = None
-    ocr_out = None
-    text_out = None
-    if is_ocr_required(page_context):
-        if options.rotate_pages:
-            # Rasterize
-            rasterize_preview_out = rasterize_preview(page_context.origin, page_context)
-            orientation_correction = get_orientation_correction(
-                rasterize_preview_out, page_context
-            )

-        rasterize_out = rasterize(
-            page_context.origin,
+    ocr_image = preprocess_out = None
+    rasterize_out = rasterize(
+        page_context.origin,
+        page_context,
+        correction=orientation_correction,
+        remove_vectors=False,
+    )
+
+    if not any([options.clean, options.clean_final, options.remove_vectors]):
+        ocr_image = preprocess_out = preprocess(
            page_context,
-            correction=orientation_correction,
-            remove_vectors=False,
+            rasterize_out,
+            options.remove_background,
+            options.deskew,
+            clean=False,
        )
-
-        if not any([options.clean, options.clean_final, options.remove_vectors]):
-            ocr_image = preprocess_out = preprocess(
+    else:
+        if not options.lossless_reconstruction:
+            preprocess_out = preprocess(
                page_context,
                rasterize_out,
                options.remove_background,
                options.deskew,
-                clean=False,
+                clean=options.clean_final,
+            )
+        if options.remove_vectors:
+            rasterize_ocr_out = rasterize(
+                page_context.origin,
+                page_context,
+                correction=orientation_correction,
+                remove_vectors=True,
+                output_tag='_ocr',
            )
        else:
-            if not options.lossless_reconstruction:
-                preprocess_out = preprocess(
-                    page_context,
-                    rasterize_out,
-                    options.remove_background,
-                    options.deskew,
-                    clean=options.clean_final,
-                )
-            if options.remove_vectors:
-                rasterize_ocr_out = rasterize(
-                    page_context.origin,
-                    page_context,
-                    correction=orientation_correction,
-                    remove_vectors=True,
-                    output_tag='_ocr',
-                )
-            else:
-                rasterize_ocr_out = rasterize_out
+            rasterize_ocr_out = rasterize_out
+
+        if (
+            preprocess_out
+            and rasterize_ocr_out == rasterize_out
+            and options.clean == options.clean_final
+        ):
+            # Optimization: image for OCR is identical to presentation image
+            ocr_image = preprocess_out
+        else:
            ocr_image = preprocess(
                page_context,
                rasterize_ocr_out,
@@ -136,28 +162,56 @@ def exec_page_sync(page_context):
                options.deskew,
                clean=options.clean,
            )
+    return ocr_image, preprocess_out

-        ocr_image_out = create_ocr_image(ocr_image, page_context)

-        pdf_page_from_image_out = None
-        if not options.lossless_reconstruction:
-            visible_image_out = preprocess_out
-            if should_visible_page_image_use_jpg(page_context.pageinfo):
-                visible_image_out = create_visible_page_jpg(
-                    visible_image_out, page_context
-                )
-            pdf_page_from_image_out = create_pdf_page_from_image(
-                visible_image_out, page_context
-            )
+def exec_page_sync(page_context: PageContext):
+    options = page_context.options
+    tls.pageno = page_context.pageno + 1

-        if options.pdf_renderer == 'hocr':
-            (hocr_out, text_out) = ocr_tesseract_hocr(ocr_image_out, page_context)
-            ocr_out = render_hocr_page(hocr_out, page_context)
+    if not is_ocr_required(page_context):
+        return PageResult(
+            pageno=page_context.pageno,
+            pdf_page_from_image=None,
+            ocr=None,
+            text=None,
+            orientation_correction=0,
+        )

-        if options.pdf_renderer == 'sandwich':
-            (ocr_out, text_out) = ocr_tesseract_textonly_pdf(
-                ocr_image_out, page_context
-            )
+    orientation_correction = 0
+    if options.rotate_pages:
+        # Rasterize
+        rasterize_preview_out = rasterize_preview(page_context.origin, page_context)
+        orientation_correction = get_orientation_correction(
+            rasterize_preview_out, page_context
+        )
+
+    ocr_image, preprocess_out = make_intermediate_images(
+        page_context, orientation_correction
+    )
+    ocr_image_out = create_ocr_image(ocr_image, page_context)
+
+    pdf_page_from_image_out = None
+    if not options.lossless_reconstruction:
+        assert preprocess_out
+        visible_image_out = preprocess_out
+        if should_visible_page_image_use_jpg(page_context.pageinfo):
+            visible_image_out = create_visible_page_jpg(visible_image_out, page_context)
+        filtered_image = page_context.plugin_manager.hook.filter_page_image(
+            page=page_context, image_filename=visible_image_out
+        )
+        if filtered_image:
+            visible_image_out = filtered_image
+        pdf_page_from_image_out = create_pdf_page_from_image(
+            visible_image_out, page_context
+        )
+
+    if options.pdf_renderer == 'hocr':
+        (hocr_out, text_out) = ocr_engine_hocr(ocr_image_out, page_context)
+        ocr_out = render_hocr_page(hocr_out, page_context)
+
+    if options.pdf_renderer == 'sandwich':
+        (ocr_out, text_out) = ocr_engine_textonly_pdf(ocr_image_out, page_context)

    return PageResult(
        pageno=page_context.pageno,
@@ -168,7 +222,7 @@ def exec_page_sync(page_context):
    )


-def post_process(pdf_file, context):
+def post_process(pdf_file, context: PdfContext):
    pdf_out = pdf_file
    if context.options.output_type.startswith('pdfa'):
        ps_stub_out = generate_postscript_stub(context)
@@ -178,138 +232,51 @@ def post_process(pdf_file, context):
    return optimize_pdf(pdf_out, context)


-def worker_init(queue, max_pixels):
-    """Initialize a process pool worker"""
-
-    # Ignore SIGINT (our parent process will kill us gracefully)
-    signal.signal(signal.SIGINT, signal.SIG_IGN)
-
-    # Reconfigure the root logger for this process to send all messages to a queue
-    h = logging.handlers.QueueHandler(queue)
-    root = logging.getLogger()
-    root.handlers = []
-    root.addHandler(h)
-
+def worker_init(max_pixels: int):
    # In Windows, child process will not inherit our change to this value in
-    # the parent process, so ensure workers get it set
+    # the parent process, so ensure workers get it set. Not needed when running
+    # threaded, but harmless to set again.
    PIL.Image.MAX_IMAGE_PIXELS = max_pixels
+    pikepdf_enable_mmap()


-def worker_thread_init(_queue, max_pixels):
-    # This is probably not needed since threads should all see the same memory,
-    # but done for consistency.
-    PIL.Image.MAX_IMAGE_PIXELS = max_pixels
-
-
-def log_listener(queue):
-    """Listen to the worker processes and forward the messages to logging
-
-    For simplicity this is a thread rather than a process. Only one process
-    should actually write to sys.stderr or whatever we're using, so if this is
-    made into a process the main application needs to be directed to it.
-
-    See https://docs.python.org/3/howto/logging-cookbook.html#logging-to-a-single-file-from-multiple-processes
-    """
-
-    while True:
-        try:
-            record = queue.get()
-            if record is None:
-                break
-            logger = logging.getLogger(record.name)
-            logger.handle(record)
-        except Exception:
-            import traceback
-
-            print("Logging problem", file=sys.stderr)
-            traceback.print_exc(file=sys.stderr)
-
-
-def exec_concurrent(context):
+def exec_concurrent(context: PdfContext):
    """Execute the pipeline concurrently"""

    # Run exec_page_sync on every page context
    max_workers = min(len(context.pdfinfo), context.options.jobs)
    if max_workers > 1:
-        context.log.info("Start processing %d pages concurrently", max_workers)
+        log.info("Start processing %d pages concurrently", max_workers)

-    # Tesseract 4.x can be multithreaded, and we also run multiple workers. We want
-    # to manage how many threads it uses to avoid creating total threads than cores.
-    # Performance testing shows we're better off
-    # parallelizing ocrmypdf and forcing Tesseract to be single threaded, which we
-    # get by setting the envvar OMP_THREAD_LIMIT to 1. But if the page count of the
-    # input file is small, then we allow Tesseract to use threads, subject to the
-    # constraint: (ocrmypdf workers) * (tesseract threads) <= max_workers.
-    # As of Tesseract 4.1, 3 threads is the most effective on a 4 core/8 thread system.
-    tess_threads = min(3, context.options.jobs // max_workers)
-    if context.options.tesseract_env is None:
-        context.options.tesseract_env = os.environ.copy()
-    context.options.tesseract_env.setdefault('OMP_THREAD_LIMIT', str(tess_threads))
-    try:
-        tess_threads = int(context.options.tesseract_env['OMP_THREAD_LIMIT'])
-    except ValueError:  # OMP_THREAD_LIMIT initialized to non-numeric
-        context.log.error("Environment variable OMP_THREAD_LIMIT is not numeric")
-    if tess_threads > 1:
-        context.log.info("Using Tesseract OpenMP thread limit %d", tess_threads)
-
-    if context.options.use_threads:
-        from multiprocessing.dummy import Pool
-
-        initializer = worker_thread_init
-    else:
-        Pool = multiprocessing.Pool
-        initializer = worker_init
-
-    sidecars = [None] * len(context.pdfinfo)
+    sidecars: List[Optional[Path]] = [None] * len(context.pdfinfo)
    ocrgraft = OcrGrafter(context)

-    log_queue = multiprocessing.Queue(-1)
-    listener = threading.Thread(target=log_listener, args=(log_queue,))
-    listener.start()
-    with tqdm(
-        total=(2 * len(context.pdfinfo)),
-        desc='OCR',
-        unit='page',
-        unit_scale=0.5,
-        disable=not context.options.progress_bar,
-    ) as pbar:
-        pool = Pool(
-            processes=max_workers,
-            initializer=initializer,
-            initargs=(log_queue, PIL.Image.MAX_IMAGE_PIXELS),
+    def update_page(result: PageResult, pbar):
+        sidecars[result.pageno] = result.text
+        pbar.update()
+        ocrgraft.graft_page(
+            pageno=result.pageno,
+            image=result.pdf_page_from_image,
+            textpdf=result.ocr,
+            autorotate_correction=result.orientation_correction,
        )
-        try:
-            results = pool.imap_unordered(exec_page_sync, context.get_page_contexts())
-            while True:
-                try:
-                    page_result = results.next()
-                    sidecars[page_result.pageno] = page_result.text
-                    pbar.update()
-                    ocrgraft.graft_page(page_result)
-                    pbar.update()
-                except StopIteration:
-                    break
-        except KeyboardInterrupt:
-            # Terminate pool so we exit instantly
-            pool.terminate()
-            # Don't try listener.join() here, will deadlock
-            raise
-        except Exception:
-            if not os.environ.get("PYTEST_CURRENT_TEST", ""):
-                # Unless inside pytest, exit immediately because no one wants
-                # to wait for child processes to finalize results that will be
-                # thrown away. Inside pytest, we want child processes to exit
-                # cleanly so that they output an error messages or coverage data
-                # we need from them.
-                pool.terminate()
-            raise
-        finally:
-            # Terminate log listener
-            log_queue.put_nowait(None)
-            pool.close()
-            pool.join()
+        pbar.update()

-    listener.join()
+    exec_progress_pool(
+        use_threads=context.options.use_threads,
+        max_workers=max_workers,
+        tqdm_kwargs=dict(
+            total=(2 * len(context.pdfinfo)),
+            desc='OCR',
+            unit='page',
+            unit_scale=0.5,
+            disable=not context.options.progress_bar,
+        ),
+        task_initializer=partial(worker_init, PIL.Image.MAX_IMAGE_PIXELS),
+        task=exec_page_sync,
+        task_arguments=context.get_page_contexts(),
+        task_finished=update_page,
+    )

    # Output sidecar text
    if context.options.sidecar:
@@ -333,61 +300,55 @@ class NeverRaise(Exception):
    pass  # pylint: disable=unnecessary-pass


-def samefile(f1, f2):
-    if os.name == 'nt':
-        return f1 == f2
-    else:
-        return os.path.samefile(f1, f2)
-
-
 def configure_debug_logging(log_filename, prefix=''):
    log_file_handler = logging.FileHandler(log_filename, delay=True)
    log_file_handler.setLevel(logging.DEBUG)
    formatter = logging.Formatter(
-        '[%(asctime)s] - %(name)s - %(levelname)7s - %(message)s'
+        '[%(asctime)s] - %(name)s - %(levelname)7s -%(pageno)s %(message)s'
    )
    log_file_handler.setFormatter(formatter)
+    log_file_handler.addFilter(PageNumberFilter())
    logging.getLogger(prefix).addHandler(log_file_handler)
    return log_file_handler


-def run_pipeline(options, api=False):
-    log = make_logger(options, __name__)
-
+def run_pipeline(options, *, plugin_manager, api=False):
    # Any changes to options will not take effect for options that are already
    # bound to function parameters in the pipeline. (For example
    # options.input_file, options.pdf_renderer are already bound.)
    if not options.jobs:
        options.jobs = available_cpu_count()
+    if not plugin_manager:
+        plugin_manager = get_plugin_manager(options.plugins)

-    work_folder = mkdtemp(prefix="com.github.ocrmypdf.")
+    work_folder = Path(mkdtemp(prefix="com.github.ocrmypdf."))
    debug_log_handler = None
    if (options.keep_temporary_files or options.verbose >= 1) and not os.environ.get(
        'PYTEST_CURRENT_TEST', ''
    ):
        debug_log_handler = configure_debug_logging(Path(work_folder) / "debug.log")

+    pikepdf_enable_mmap()
+
    try:
        check_requested_output_file(options)
        start_input_file, original_filename = create_input_file(options, work_folder)

        # Triage image or pdf
        origin_pdf = triage(
-            original_filename,
-            start_input_file,
-            os.path.join(work_folder, 'origin.pdf'),
-            options,
-            log,
+            original_filename, start_input_file, work_folder / 'origin.pdf', options
        )

        # Gather pdfinfo and create context
        pdfinfo = get_pdfinfo(
            origin_pdf,
-            detailed_page_analysis=options.redo_ocr,
+            detailed_analysis=options.redo_ocr,
            progbar=options.progress_bar,
+            max_workers=options.jobs if not options.use_threads else 1,  # To help debug
+            check_pages=options.pages,
        )

-        context = PDFContext(options, work_folder, origin_pdf, pdfinfo)
+        context = PdfContext(options, work_folder, origin_pdf, pdfinfo, plugin_manager)

        # Validate options are okay for this pdf
        validate_pdfinfo_options(context)
@@ -397,6 +358,10 @@ def run_pipeline(options, api=False):

        if options.output_file == '-':
            log.info("Output sent to stdout")
+        elif (
+            hasattr(options.output_file, 'writable') and options.output_file.writable()
+        ):
+            log.info("Output written to stream")
        elif samefile(options.output_file, os.devnull):
            pass  # Say nothing when sending to dev null
        else:
@@ -412,7 +377,7 @@ def run_pipeline(options, api=False):
                        pdfa_info['conformance'],
                    )
                    return ExitCode.pdfa_conversion_failed
-            if not qpdf.check(options.output_file, log):
+            if not check_pdf(options.output_file):
                log.warning('Output file: The generated PDF is INVALID')
                return ExitCode.invalid_output_pdf
            report_output_file_size(options, start_input_file, options.output_file)
@@ -429,7 +394,7 @@ def run_pipeline(options, api=False):
        else:
            log.error(type(e).__name__)
        return e.exit_code
-    except (Exception if not api else NeverRaise) as e:
+    except (Exception if not api else NeverRaise) as e:  # pylint: disable=broad-except
        log.exception("An exception occurred while executing the pipeline")
        return ExitCode.other_error
    finally:
@@ -1,48 +1,38 @@
 #!/usr/bin/env python3
 # © 2015-17 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.


 import locale
 import logging
 import os
 import sys
+import unicodedata
 from pathlib import Path
 from shutil import copyfileobj
+from typing import Tuple

+import pikepdf
 import PIL

-from ._unicodefun import verify_python3_env
-from .exceptions import (
+from ocrmypdf._exec import jbig2enc, pngquant, unpaper
+from ocrmypdf._unicodefun import verify_python3_env
+from ocrmypdf.exceptions import (
    BadArgsError,
    InputFileError,
    MissingDependencyError,
    OutputFileAccessError,
 )
-from .exec import (
-    check_external_program,
-    ghostscript,
-    jbig2enc,
-    pngquant,
-    qpdf,
-    tesseract,
-    unpaper,
+from ocrmypdf.helpers import (
+    is_file_writable,
+    is_iterable_notstr,
+    monotonic,
+    safe_symlink,
 )
-from .helpers import is_file_writable, is_iterable_notstr, monotonic, safe_symlink
+from ocrmypdf.subprocess import check_external_program

 # -------------
 # External dependencies
@@ -67,35 +57,26 @@ def check_platform():
        )


-def check_options_languages(options):
-    if not options.language:
-        options.language = [DEFAULT_LANGUAGE]
+def check_options_languages(options, ocr_engine_languages):
+    if not options.languages:
+        options.languages = {DEFAULT_LANGUAGE}
        system_lang = locale.getlocale()[0]
        if system_lang and not system_lang.startswith('en'):
            log.debug("No language specified; assuming --language %s", DEFAULT_LANGUAGE)
-
-    # Support v2.x "eng+deu" language syntax
-    if '+' in options.language[0]:
-        options.language = options.language[0].split('+')
-
-    languages = set(options.language)
-    if not languages.issubset(tesseract.languages()):
+    if not ocr_engine_languages:
+        return
+    if not options.languages.issubset(ocr_engine_languages):
        msg = (
-            "The installed version of tesseract does not have language "
-            "data for the following requested languages: \n"
+            f"OCR engine does not have language data for the following "
+            "requested languages: \n"
        )
-        for lang in languages - tesseract.languages():
+        for lang in options.languages - ocr_engine_languages:
            msg += lang + '\n'
        raise MissingDependencyError(msg)


 def check_options_output(options):
-    # We have these constraints to check for.
-    # 1. Ghostscript < 9.20 mangles multibyte Unicode
-    # 2. hocr doesn't work on non-Latin languages (so don't select it)
-
-    languages = set(options.language)
-    is_latin = languages.issubset(HOCR_OK_LANGS)
+    is_latin = options.languages.issubset(HOCR_OK_LANGS)

    if options.pdf_renderer == 'hocr' and not is_latin:
        msg = (
@@ -105,37 +86,6 @@ def check_options_output(options):
        )
        log.warning(msg)

-    if ghostscript.version() < '9.20' and options.output_type != 'pdf' and not is_latin:
-        # https://bugs.ghostscript.com/show_bug.cgi?id=696874
-        # Ghostscript < 9.20 fails to encode multibyte characters properly
-        msg = (
-            "The installed version of Ghostscript does not work correctly "
-            "with the OCR languages you specified. Use --output-type pdf or "
-            "upgrade to Ghostscript 9.20 or later to avoid this issue."
-        )
-        msg += f"Found Ghostscript {ghostscript.version()}"
-        log.warning(msg)
-
-    # Decide on what renderer to use
-    if options.pdf_renderer == 'auto':
-        options.pdf_renderer = 'sandwich'
-
-    if options.pdf_renderer == 'sandwich' and not tesseract.has_textonly_pdf(
-        options.tesseract_env, languages
-    ):
-        raise MissingDependencyError(
-            "You are using an alpha version of Tesseract 4.0 that does not support "
-            "the textonly_pdf parameter. We don't support versions this old."
-        )
-
-    if options.output_type == 'pdfa':
-        options.output_type = 'pdfa-2'
-
-    if options.output_type == 'pdfa-3' and ghostscript.version() < '9.19':
-        raise MissingDependencyError(
-            "--output-type pdfa-3 requires Ghostscript 9.19 or later"
-        )
-
    lossless_reconstruction = False
    if not any(
        (
@@ -270,18 +220,9 @@ def check_options_advanced(options):
            "--pdfa-image-compression argument has no effect when "
            "--output-type is not 'pdfa', 'pdfa-1', or 'pdfa-2'"
        )
-    if not tesseract.has_user_words(options.tesseract_env) and (
-        options.user_words or options.user_patterns
-    ):
-        log.warning(
-            "Tesseract 4.0 ignores --user-words and --user-patterns, so these "
-            "arguments have no effect."
-        )


 def check_options_metadata(options):
-    import unicodedata
-
    docinfo = [options.title, options.author, options.keywords, options.subject]
    for s in (m for m in docinfo if m):
        for c in s:
@@ -300,9 +241,9 @@ def check_options_pillow(options):
        PIL.Image.MAX_IMAGE_PIXELS = None


-def check_options(options):
+def _check_options(options, plugin_manager, ocr_engine_languages):
    check_platform()
-    check_options_languages(options)
+    check_options_languages(options, ocr_engine_languages)
    check_options_metadata(options)
    check_options_output(options)
    check_options_sidecar(options)
@@ -311,7 +252,12 @@ def check_options(options):
    check_options_optimizing(options)
    check_options_advanced(options)
    check_options_pillow(options)
-    check_dependency_versions(options)
+    plugin_manager.hook.check_options(options=options)
+
+
+def check_options(options, plugin_manager):
+    ocr_engine_languages = plugin_manager.hook.get_ocr_engine().languages(options)
+    _check_options(options, plugin_manager, ocr_engine_languages)


 def check_closed_streams(options):  # pragma: no cover
@@ -373,17 +319,25 @@ def log_page_orientations(pdfinfo):
        log.info('Page orientations detected: %s', ' '.join(orientations))


-def create_input_file(options, work_folder):
+def create_input_file(options, work_folder: Path) -> Tuple[Path, str]:
    if options.input_file == '-':
        # stdin
        log.info('reading file from standard input')
-        target = os.path.join(work_folder, 'stdin')
+        target = work_folder / 'stdin'
        with open(target, 'wb') as stream_buffer:
            copyfileobj(sys.stdin.buffer, stream_buffer)
-        return target, "<stdin>"
+        return target, "stdin"
+    elif hasattr(options.input_file, 'readable'):
+        if not options.input_file.readable():
+            raise InputFileError("Input file stream is not readable")
+        log.info('reading file from input stream')
+        target = work_folder / 'stream'
+        with open(target, 'wb') as stream_buffer:
+            copyfileobj(options.input_file, stream_buffer)
+        return target, "stream"
    else:
        try:
-            target = os.path.join(work_folder, 'origin')
+            target = work_folder / 'origin'
            safe_symlink(options.input_file, target)
            return target, os.fspath(options.input_file)
        except FileNotFoundError:
@@ -398,6 +352,9 @@ def check_requested_output_file(options):
                "is connected to a terminal.  Please redirect stdout to a "
                "file."
            )
+    elif hasattr(options.output_file, 'writable'):
+        if not options.output_file.writable():
+            raise OutputFileAccessError("Output stream is not writable")
    elif not is_file_writable(options.output_file):
        raise OutputFileAccessError(
            f"Output file location ({options.output_file}) is not a writable file."
@@ -410,8 +367,15 @@ def report_output_file_size(options, input_file, output_file):
        input_size = Path(input_file).stat().st_size
    except FileNotFoundError:
        return  # Outputting to stream or something
+    with pikepdf.open(output_file) as p:
+        # Overhead constants obtained by estimating amount of data added by OCR
+        # PDF/A conversion, and possible XMP metadata addition, with compression
+        FILE_OVERHEAD = 4000
+        OCR_PER_PAGE_OVERHEAD = 3000
+        reasonable_overhead = FILE_OVERHEAD + OCR_PER_PAGE_OVERHEAD * len(p.pages)
    ratio = output_size / input_size
-    if ratio < 1.35 or input_size < 25000:
+    reasonable_ratio = output_size / (input_size + reasonable_overhead)
+    if reasonable_ratio < 1.35 or input_size < 25000:
        return  # Seems fine

    reasons = []
@@ -441,6 +405,10 @@ def report_output_file_size(options, input_file, output_file):
                    f"The optional dependency '{name}' was not found, so some image "
                    f"optimizations could not be attempted."
                )
+    if options.output_type.startswith('pdfa'):
+        reasons.append("PDF/A conversion was enabled. (Try `--output-type pdf`.)")
+    if options.plugins:
+        reasons.append("Plugins were used.")

    if reasons:
        explanation = "Possible reasons for this include:\n" + '\n'.join(reasons) + "\n"
@@ -451,31 +419,3 @@ def report_output_file_size(options, input_file, output_file):
        f"The output file size is {ratio:.2f}× larger than the input file.\n"
        f"{explanation}"
    )
-
-
-def check_dependency_versions(options):
-    check_external_program(
-        program='tesseract',
-        package={'linux': 'tesseract-ocr'},
-        version_checker=tesseract.version,
-        need_version='4.0.0',  # using backport for Travis CI
-    )
-    check_external_program(
-        program='gs',
-        package='ghostscript',
-        version_checker=ghostscript.version,
-        need_version='9.15',  # limited by Travis CI / Ubuntu 14.04 backports
-    )
-    gs_version = ghostscript.version()
-    if gs_version in ('9.24', '9.51'):
-        raise MissingDependencyError(
-            f"Ghostscript {gs_version} contains serious regressions and is not "
-            "supported. Please upgrade to a newer version, or downgrade to the "
-            "previous version."
-        )
-    check_external_program(
-        program='qpdf',
-        package='qpdf',
-        version_checker=qpdf.version,
-        need_version='8.0.2',
-    )
@@ -1,19 +1,8 @@
 # © 2017 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.


 import pkg_resources
@@ -1,61 +1,31 @@
 # © 2019 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import logging
 import os
 import sys
-from contextlib import suppress
 from enum import IntEnum
 from pathlib import Path
-from typing import Dict, List
+from typing import BinaryIO, Iterable, Union

-from tqdm import tqdm
+from ocrmypdf._logging import PageNumberFilter, TqdmConsole
+from ocrmypdf._plugin_manager import get_plugin_manager
+from ocrmypdf._sync import run_pipeline
+from ocrmypdf._validation import check_options
+from ocrmypdf.cli import ArgumentParser, get_parser
+from ocrmypdf.helpers import is_iterable_notstr

-from ._sync import run_pipeline
-from ._validation import check_options
-from .cli import parser
+try:
+    import coloredlogs
+except ModuleNotFoundError:
+    coloredlogs = None


-class TqdmConsole:
-    """Wrapper to log messages in a way that is compatible with tqdm progress bar
-
-    This routes log messages through tqdm so that it can print them above the
-    progress bar, and then refresh the progress bar, rather than overwriting
-    it which looks messy.
-
-    For some reason Python 3.6 prints extra empty messages from time to time,
-    so we suppress those.
-    """
-
-    def __init__(self, file):
-        self.file = file
-        self.py36 = sys.version_info[0:2] == (3, 6)
-
-    def write(self, msg):
-        # When no progress bar is active, tqdm.write() routes to print()
-        if self.py36:
-            if msg.strip() != '':
-                tqdm.write(msg.rstrip(), end='\n', file=self.file)
-        else:
-            tqdm.write(msg.rstrip(), end='\n', file=self.file)
-
-    def flush(self):
-        with suppress(AttributeError):
-            self.file.flush()
+PathOrIO = Union[BinaryIO, os.PathLike, str, bytes]


 class Verbosity(IntEnum):
@@ -67,7 +37,11 @@ class Verbosity(IntEnum):
    debug_all = 2  #: More detailed debugging from ocrmypdf and dependent modules


-def configure_logging(verbosity, progress_bar_friendly=True, manage_root_logger=False):
+def configure_logging(
+    verbosity: Verbosity,
+    progress_bar_friendly: bool = True,
+    manage_root_logger: bool = False,
+):
    """Set up logging.

    Library users may wish to use this function if they want their log output to be
@@ -94,6 +68,7 @@ def configure_logging(verbosity, progress_bar_friendly=True, manage_root_logger=
    """

    prefix = '' if manage_root_logger else 'ocrmypdf'
+
    log = logging.getLogger(prefix)
    log.setLevel(logging.DEBUG)

@@ -109,9 +84,25 @@ def configure_logging(verbosity, progress_bar_friendly=True, manage_root_logger=
    else:
        console.setLevel(logging.INFO)

-    formatter = logging.Formatter('%(levelname)7s - %(message)s')
+    console.addFilter(PageNumberFilter())
+
    if verbosity >= 2:
-        formatter = logging.Formatter('%(name)s - %(levelname)7s - %(message)s')
+        fmt = '%(levelname)7s %(name)s -%(pageno)s %(message)s'
+    else:
+        fmt = '%(pageno)s%(message)s'
+
+    use_colors = progress_bar_friendly
+    if not coloredlogs:
+        use_colors = False
+    if use_colors:
+        if os.name == 'nt':
+            use_colors = coloredlogs.enable_ansi_support()
+        if use_colors:
+            use_colors = coloredlogs.terminal_supports_colors()
+    if use_colors:
+        formatter = coloredlogs.ColoredFormatter(fmt=fmt)
+    else:
+        formatter = logging.Formatter(fmt=fmt)

    console.setFormatter(formatter)
    log.addHandler(console)
@@ -128,7 +119,9 @@ def configure_logging(verbosity, progress_bar_friendly=True, manage_root_logger=
    return log


-def create_options(*, input_file, output_file, **kwargs):
+def create_options(
+    *, input_file: PathOrIO, output_file: PathOrIO, parser: ArgumentParser, **kwargs
+):
    cmdline = []
    deferred = []

@@ -138,7 +131,7 @@ def create_options(*, input_file, output_file, **kwargs):

        # These arguments with special handling for which we bypass
        # argparse
-        if arg in {'tesseract_env', 'progress_bar'}:
+        if arg in {'progress_bar', 'plugins'}:
            deferred.append((arg, val))
            continue

@@ -150,6 +143,12 @@ def create_options(*, input_file, output_file, **kwargs):
                cmdline.append(f"--{cmd_style_arg}")
            continue

+        if is_iterable_notstr(val):
+            for elem in val:
+                cmdline.append(f"--{cmd_style_arg}")
+                cmdline.append(elem)
+            continue
+
        # We have a parameter
        cmdline.append(f"--{cmd_style_arg}")
        if isinstance(val, (int, float)):
@@ -161,26 +160,33 @@ def create_options(*, input_file, output_file, **kwargs):
        else:
            raise TypeError(f"{arg}: {val} ({type(val)})")

-    cmdline.append(str(input_file))
-    cmdline.append(str(output_file))
+    try:
+        cmdline.append(os.fspath(input_file))
+    except TypeError:
+        cmdline.append('stream://input_file')
+    try:
+        cmdline.append(os.fspath(output_file))
+    except TypeError:
+        cmdline.append('stream://output_file')

-    parser.api_mode = True
+    parser._api_mode = True
    options = parser.parse_args(cmdline)
    for keyword, val in deferred:
        setattr(options, keyword, val)

-    # If we are running a Tesseract spoof, ensure it knows what the input file is
-    if os.environ.get('PYTEST_CURRENT_TEST') and options.tesseract_env:
-        options.tesseract_env['_OCRMYPDF_TEST_INFILE'] = os.fspath(input_file)
+    if options.input_file == 'stream://input_file':
+        options.input_file = input_file
+    if options.output_file == 'stream://output_file':
+        options.output_file = output_file

    return options


 def ocr(  # pylint: disable=unused-argument
-    input_file: os.PathLike,
-    output_file: os.PathLike,
+    input_file: PathOrIO,
+    output_file: PathOrIO,
    *,
-    language: List[str] = None,
+    language: Iterable[str] = None,
    image_dpi: int = None,
    output_type=None,
    sidecar: os.PathLike = None,
@@ -210,7 +216,7 @@ def ocr(  # pylint: disable=unused-argument
    jbig2_page_group_size: int = None,
    pages: str = None,
    max_image_mpixels: float = None,
-    tesseract_config: List[str] = None,
+    tesseract_config: Iterable[str] = None,
    tesseract_pagesegmode: int = None,
    tesseract_oem: int = None,
    pdf_renderer=None,
@@ -220,9 +226,10 @@ def ocr(  # pylint: disable=unused-argument
    user_words: os.PathLike = None,
    user_patterns: os.PathLike = None,
    fast_web_view: float = None,
+    plugins: Iterable[str] = None,
    keep_temporary_files: bool = None,
    progress_bar: bool = None,
-    tesseract_env: Dict[str, str] = None,
+    **kwargs,
 ):
    """Run OCRmyPDF on one PDF or image.

@@ -230,10 +237,24 @@ def ocr(  # pylint: disable=unused-argument
    A few specific arguments are discussed here:

    Args:
-        use_threads (bool): Use worker threads instead of processes. This reduces
+        use_threads: Use worker threads instead of processes. This reduces
            performance but may make debugging easier since it is easier to set
            breakpoints.
-        tesseract_env (dict): Override environment variables for Tesseract
+        input_file: If a :class:`pathlib.Path`, ``str`` or ``bytes``, this is
+            interpreted as file system path to the input file. If the object
+            appears to be a readable stream (with methods such as ``.read()``
+            and ``.seek()``), the object will be read in its entirety and saved to
+            a temporary file. If ``input_file`` is  ``"-"``, standard input will be
+            read.
+        output_file: If a :class:`pathlib.Path`, ``str`` or ``bytes``, this is
+            interpreted as file system path to the output file. If the object
+            appears to be a writable stream (with methods such as ``.read()`` and
+            ``.seek()``), the output will be written to this stream. If
+            ``output_file`` is ``"-"``, the output will be written to ``sys.stdout``
+            (provided that standard output does not seem to be a terminal device).
+            When a stream is used as output, whether via a writable object or
+            ``"-"``, some final validation steps are not performed (we do not read
+            back the stream after it is written).
    Raises:
        ocrmypdf.PdfMergeFailedError: If the input PDF is malformed, preventing merging
            with the OCR layer.
@@ -257,7 +278,20 @@ def ocr(  # pylint: disable=unused-argument
    Returns:
        :class:`ocrmypdf.ExitCode`
    """
+    if not plugins:
+        plugins = []
+    else:
+        plugins = list(plugins)

-    options = create_options(**locals())
-    check_options(options)
-    return run_pipeline(options, api=True)
+    parser = get_parser()
+    _plugin_manager = get_plugin_manager(plugins)
+    _plugin_manager.hook.add_options(parser=parser)  # pylint: disable=no-member
+
+    create_options_kwargs = {
+        k: v for k, v in locals().items() if not k.startswith('_') and k != 'kwargs'
+    }
+    create_options_kwargs.update(kwargs)
+
+    options = create_options(**create_options_kwargs)
+    check_options(options, _plugin_manager)
+    return run_pipeline(options=options, plugin_manager=_plugin_manager, api=True)
@@ -0,0 +1,5 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
@@ -0,0 +1,92 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+import logging
+
+from ocrmypdf import hookimpl
+from ocrmypdf._exec import ghostscript
+from ocrmypdf._validation import HOCR_OK_LANGS
+from ocrmypdf.exceptions import MissingDependencyError
+from ocrmypdf.subprocess import check_external_program
+
+log = logging.getLogger(__name__)
+
+
+@hookimpl
+def check_options(options):
+    gs_version = ghostscript.version()
+    check_external_program(
+        program='gs',
+        package='ghostscript',
+        version_checker=gs_version,
+        need_version='9.15',  # limited by Travis CI / Ubuntu 14.04 backports
+    )
+    if gs_version in ('9.24', '9.51'):
+        raise MissingDependencyError(
+            f"Ghostscript {gs_version} contains serious regressions and is not "
+            "supported. Please upgrade to a newer version, or downgrade to the "
+            "previous version."
+        )
+
+    # We have these constraints to check for.
+    # 1. Ghostscript < 9.20 mangles multibyte Unicode
+    # 2. hocr doesn't work on non-Latin languages (so don't select it)
+    is_latin = options.languages.issubset(HOCR_OK_LANGS)
+    if gs_version < '9.20' and options.output_type != 'pdf' and not is_latin:
+        # https://bugs.ghostscript.com/show_bug.cgi?id=696874
+        # Ghostscript < 9.20 fails to encode multibyte characters properly
+        msg = (
+            "The installed version of Ghostscript does not work correctly "
+            "with the OCR languages you specified. Use --output-type pdf or "
+            "upgrade to Ghostscript 9.20 or later to avoid this issue."
+        )
+        msg += f"Found Ghostscript {gs_version}"
+        log.warning(msg)
+
+    if options.output_type == 'pdfa':
+        options.output_type = 'pdfa-2'
+
+    if options.output_type == 'pdfa-3' and ghostscript.version() < '9.19':
+        raise MissingDependencyError(
+            "--output-type pdfa-3 requires Ghostscript 9.19 or later"
+        )
+
+
+@hookimpl
+def rasterize_pdf_page(
+    input_file,
+    output_file,
+    raster_device,
+    raster_dpi,
+    pageno,
+    page_dpi=None,
+    rotation=None,
+    filter_vector=False,
+):
+    ghostscript.rasterize_pdf(
+        input_file,
+        output_file,
+        raster_device=raster_device,
+        raster_dpi=raster_dpi,
+        pageno=pageno,
+        page_dpi=page_dpi,
+        rotation=rotation,
+        filter_vector=filter_vector,
+    )
+    return output_file
+
+
+@hookimpl
+def generate_pdfa(pdf_pages, pdfmark, output_file, compression, pdf_version, pdfa_part):
+    ghostscript.generate_pdfa(
+        pdf_pages=[*pdf_pages, pdfmark],
+        output_file=output_file,
+        compression=compression,
+        pdf_version=pdf_version,
+        pdfa_part=pdfa_part,
+    )
+    return output_file
@@ -0,0 +1,187 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+import logging
+import os
+
+from ocrmypdf import hookimpl
+from ocrmypdf._exec import tesseract
+from ocrmypdf.cli import numeric
+from ocrmypdf.exceptions import MissingDependencyError
+from ocrmypdf.helpers import clamp
+from ocrmypdf.pluginspec import OcrEngine
+from ocrmypdf.subprocess import check_external_program
+
+log = logging.getLogger(__name__)
+
+
+@hookimpl
+def add_options(parser):
+    tess = parser.add_argument_group("Tesseract", "Advanced control of Tesseract OCR")
+    tess.add_argument(
+        '--tesseract-config',
+        action='append',
+        metavar='CFG',
+        default=[],
+        help="Additional Tesseract configuration files -- see documentation",
+    )
+    tess.add_argument(
+        '--tesseract-pagesegmode',
+        action='store',
+        type=int,
+        metavar='PSM',
+        choices=range(0, 14),
+        help="Set Tesseract page segmentation mode (see tesseract --help)",
+    )
+    tess.add_argument(
+        '--tesseract-oem',
+        action='store',
+        type=int,
+        metavar='MODE',
+        choices=range(0, 4),
+        help=(
+            "Set Tesseract 4.0 OCR engine mode: "
+            "0 - original Tesseract only; "
+            "1 - neural nets LSTM only; "
+            "2 - Tesseract + LSTM; "
+            "3 - default."
+        ),
+    )
+    tess.add_argument(
+        '--tesseract-timeout',
+        default=180.0,
+        type=numeric(float, 0),
+        metavar='SECONDS',
+        help='Give up on OCR after the timeout, but copy the preprocessed page '
+        'into the final output',
+    )
+    tess.add_argument(
+        '--user-words',
+        metavar='FILE',
+        help="Specify the location of the Tesseract user words file. This is a "
+        "list of words Tesseract should consider while performing OCR in "
+        "addition to its standard language dictionaries. This can improve "
+        "OCR quality especially for specialized and technical documents.",
+    )
+    tess.add_argument(
+        '--user-patterns',
+        metavar='FILE',
+        help="Specify the location of the Tesseract user patterns file.",
+    )
+
+
+@hookimpl
+def check_options(options):
+    check_external_program(
+        program='tesseract',
+        package={'linux': 'tesseract-ocr'},
+        version_checker=tesseract.version,
+        need_version='4.0.0',  # using backport for Travis CI
+    )
+
+    # Decide on what renderer to use
+    if options.pdf_renderer == 'auto':
+        options.pdf_renderer = 'sandwich'
+
+    if options.pdf_renderer == 'sandwich' and not tesseract.has_textonly_pdf(
+        set(options.languages)
+    ):
+        raise MissingDependencyError(
+            "You are using an alpha version of Tesseract 4.0 that does not support "
+            "the textonly_pdf parameter. We don't support versions this old."
+        )
+    if not tesseract.has_user_words() and (options.user_words or options.user_patterns):
+        log.warning(
+            "Tesseract 4.0 ignores --user-words and --user-patterns, so these "
+            "arguments have no effect."
+        )
+    if options.tesseract_pagesegmode in (0, 2):
+        log.warning(
+            "The --tesseract-pagesegmode argument you select will disable OCR. "
+            "This may cause processing to fail."
+        )
+
+
+@hookimpl
+def validate(pdfinfo, options):
+    # Tesseract 4.x can be multithreaded, and we also run multiple workers. We want
+    # to manage how many threads it uses to avoid creating total threads than cores.
+    # Performance testing shows we're better off
+    # parallelizing ocrmypdf and forcing Tesseract to be single threaded, which we
+    # get by setting the envvar OMP_THREAD_LIMIT to 1. But if the page count of the
+    # input file is small, then we allow Tesseract to use threads, subject to the
+    # constraint: (ocrmypdf workers) * (tesseract threads) <= max_workers.
+    # As of Tesseract 4.1, 3 threads is the most effective on a 4 core/8 thread system.
+    if not os.environ.get('OMP_THREAD_LIMIT', '').isnumeric():
+        tess_threads = clamp(options.jobs // len(pdfinfo), 1, 3)
+        os.environ['OMP_THREAD_LIMIT'] = str(tess_threads)
+    else:
+        tess_threads = int(os.environ['OMP_THREAD_LIMIT'])
+
+    if tess_threads > 1:
+        log.info("Using Tesseract OpenMP thread limit %d", tess_threads)
+
+
+class TesseractOcrEngine(OcrEngine):
+    @staticmethod
+    def version():
+        return tesseract.version()
+
+    @staticmethod
+    def creator_tag(options):
+        tag = '-PDF' if options.pdf_renderer == 'sandwich' else ''
+        return f"Tesseract OCR{tag} {TesseractOcrEngine.version()}"
+
+    def __str__(self):
+        return f"Tesseract OCR {TesseractOcrEngine.version()}"
+
+    @staticmethod
+    def languages(options):
+        return tesseract.get_languages()
+
+    @staticmethod
+    def get_orientation(input_file, options):
+        return tesseract.get_orientation(
+            input_file,
+            engine_mode=options.tesseract_oem,
+            timeout=options.tesseract_timeout,
+        )
+
+    @staticmethod
+    def generate_hocr(input_file, output_hocr, output_text, options):
+        tesseract.generate_hocr(
+            input_file=input_file,
+            output_hocr=output_hocr,
+            output_text=output_text,
+            languages=options.languages,
+            engine_mode=options.tesseract_oem,
+            tessconfig=options.tesseract_config,
+            timeout=options.tesseract_timeout,
+            pagesegmode=options.tesseract_pagesegmode,
+            user_words=options.user_words,
+            user_patterns=options.user_patterns,
+        )
+
+    @staticmethod
+    def generate_pdf(input_file, output_pdf, output_text, options):
+        tesseract.generate_pdf(
+            input_file=input_file,
+            output_pdf=output_pdf,
+            output_text=output_text,
+            languages=options.languages,
+            engine_mode=options.tesseract_oem,
+            tessconfig=options.tesseract_config,
+            timeout=options.tesseract_timeout,
+            pagesegmode=options.tesseract_pagesegmode,
+            user_words=options.user_words,
+            user_patterns=options.user_patterns,
+        )
+
+
+@hookimpl
+def get_ocr_engine():
+    return TesseractOcrEngine()
@@ -1,26 +1,14 @@
 # © 2015-19 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import argparse

-from ._version import PROGRAM_NAME as _PROGRAM_NAME
-from ._version import __version__ as _VERSION
-
-__all__ = ['parser']
+from ocrmypdf._version import PROGRAM_NAME as _PROGRAM_NAME
+from ocrmypdf._version import __version__ as _VERSION


 def numeric(basetype, min_=None, max_=None):
@@ -47,30 +35,46 @@ class ArgumentParser(argparse.ArgumentParser):

    def __init__(self, *args, **kwargs):
        super().__init__(*args, **kwargs)
-        self.api_mode = False
+        self._api_mode = False

    def error(self, message):
-        if not self.api_mode:
+        if not self._api_mode:
            super().error(message)
            return
        raise ValueError(message)


-parser = ArgumentParser(
-    prog=_PROGRAM_NAME,
-    fromfile_prefix_chars='@',
-    formatter_class=argparse.RawDescriptionHelpFormatter,
-    description="""\
+class LanguageSetAction(argparse.Action):
+    def __init__(self, option_strings, dest, default=None, **kwargs):
+        if default is None:
+            default = set()
+        super().__init__(option_strings, dest, default=default, **kwargs)
+
+    def __call__(self, parser, namespace, values, option_string=None):
+        dest = getattr(namespace, self.dest)
+        if '+' in values:
+            dest.update(lang for lang in values.split('+'))
+        else:
+            dest.add(values)
+
+
+def get_parser():
+    parser = ArgumentParser(
+        prog=_PROGRAM_NAME,
+        allow_abbrev=True,
+        fromfile_prefix_chars='@',
+        formatter_class=argparse.RawDescriptionHelpFormatter,
+        description="""\
 Generates a searchable PDF or PDF/A from a regular PDF.

 OCRmyPDF rasterizes each page of the input PDF, optionally corrects page
 rotation and performs image processing, runs the Tesseract OCR engine on the
 image, and then creates a PDF from the OCR information.
 """,
-    epilog="""\
+        epilog="""\
 OCRmyPDF attempts to keep the output file at about the same size.  If a file
-contains losslessly compressed images, and output file will be losslessly
-compressed as well.
+contains losslessly compressed images, and images in the output file will be
+losslessly compressed as well.

 PDF is a page description file that attempts to preserve a layout exactly.
 A PDF can contain vector objects (such as text or lines) and raster objects
@@ -89,9 +93,8 @@ all objects on the page and produce an image-only PDF as output.

 If you are concerned about long-term archiving of PDFs, use the default option
 --output-type pdfa which converts the PDF to a standardized PDF/A-2b.  This
-converts images to sRGB colorspace, removes some features from the PDF such
-as Javascript or forms. If you want to minimize the number of changes made to
-your PDF, use --output-type pdf.
+removes some features from the PDF such as Javascript or forms. If you want to
+minimize the number of changes made to your PDF, use --output-type pdf.

 If OCRmyPDF is given an image file as input, it will attempt to convert the
 image to a PDF before processing.  For more control over the conversion of
@@ -99,8 +102,7 @@ images to PDF, use the Python package img2pdf or other image to PDF software.

 For example, this command uses img2pdf to convert all .png files beginning
 with the 'page' prefix to a PDF, fitting each image on A4-sized paper, and
-sending the result to OCRmyPDF through a pipe.  img2pdf is a dependency of
-ocrmypdf so it is already installed.
+sending the result to OCRmyPDF through a pipe.

    img2pdf --pagesize A4 page*.png | ocrmypdf - myfile.pdf

@@ -108,386 +110,373 @@ Online documentation is located at:
    https://ocrmypdf.readthedocs.io/en/latest/introduction.html

 """,
-)
+    )

-parser.add_argument(
-    'input_file',
-    metavar="input_pdf_or_image",
-    help="PDF file containing the images to be OCRed (or '-' to read from "
-    "standard input)",
+    parser.add_argument(
+        'input_file',
+        metavar="input_pdf_or_image",
+        help="PDF file containing the images to be OCRed (or '-' to read from "
+        "standard input)",
+    )
+    parser.add_argument(
+        'output_file',
+        metavar="output_pdf",
+        help="Output searchable PDF file (or '-' to write to standard output). "
+        "Existing files will be ovewritten. If same as input file, the "
+        "input file will be updated only if processing is successful.",
+    )
+    parser.add_argument(
+        '-l',
+        '--language',
+        dest='languages',
+        action=LanguageSetAction,
+        help="Language(s) of the file to be OCRed (see tesseract --list-langs for "
+        "all language packs installed in your system). Use -l eng+deu for "
+        "multiple languages.",
+    )
+    parser.add_argument(
+        '--image-dpi',
+        metavar='DPI',
+        type=int,
+        help="For input image instead of PDF, use this DPI instead of file's.",
+    )
+    parser.add_argument(
+        '--output-type',
+        choices=['pdfa', 'pdf', 'pdfa-1', 'pdfa-2', 'pdfa-3'],
+        default='pdfa',
+        help="Choose output type. 'pdfa' creates a PDF/A-2b compliant file for "
+        "long term archiving (default, recommended) but may not suitable "
+        "for users who want their file altered as little as possible. 'pdfa' "
+        "also has problems with full Unicode text. 'pdf' attempts to "
+        "preserve file contents as much as possible. 'pdf-a1' creates a "
+        "PDF/A1-b file. 'pdf-a2' is equivalent to 'pdfa'. 'pdf-a3' creates a "
+        "PDF/A3-b file.",
+    )
+
+    # Use null string '\0' as sentinel to indicate the user supplied no argument,
+    # since that is the only invalid character for filepaths on all platforms
+    # bool('\0') is True in Python
+    parser.add_argument(
+        '--sidecar',
+        nargs='?',
+        const='\0',
+        default=None,
+        metavar='FILE',
+        help="Generate sidecar text files that contain the same text recognized "
+        "by Tesseract. This may be useful for building a OCR text database. "
+        "If FILE is omitted, the sidecar file be named {output_file}.txt "
+        "If FILE is set to '-', the sidecar is written to stdout (a "
+        "convenient way to preview OCR quality). The output file and sidecar "
+        "may not both use stdout at the same time.",
+    )
+
+    parser.add_argument(
+        '--version',
+        action='version',
+        version=_VERSION,
+        help="Print program version and exit",
+    )
+
+    jobcontrol = parser.add_argument_group("Job control options")
+    jobcontrol.add_argument(
+        '-j',
+        '--jobs',
+        metavar='N',
+        type=numeric(int, 0, 256),
+        help="Use up to N CPU cores simultaneously (default: use all).",
+    )
+    jobcontrol.add_argument(
+        '-q', '--quiet', action='store_true', help="Suppress INFO messages"
+    )
+    jobcontrol.add_argument(
+        '-v',
+        '--verbose',
+        type=numeric(int, 0, 2),
+        default=0,
+        const=1,
+        nargs='?',
+        help="Print more verbose messages for each additional verbose level. Use "
+        "`-v 1` typically for much more detailed logging. Higher numbers "
+        "are probably only useful in debugging.",
+    )
+    jobcontrol.add_argument(
+        '--no-progress-bar',
+        action='store_false',
+        dest='progress_bar',
+        help=argparse.SUPPRESS,
+    )
+    jobcontrol.add_argument(
+        '--use-threads', action='store_true', help=argparse.SUPPRESS
+    )
+
+    metadata = parser.add_argument_group(
+        "Metadata options",
+        "Set output PDF/A metadata (default: copy input document's metadata)",
+    )
+    metadata.add_argument(
+        '--title', type=str, help="Set document title (place multiple words in quotes)"
+    )
+    metadata.add_argument('--author', type=str, help="Set document author")
+    metadata.add_argument(
+        '--subject', type=str, help="Set document subject description"
+    )
+    metadata.add_argument('--keywords', type=str, help="Set document keywords")
+
+    preprocessing = parser.add_argument_group(
+        "Image preprocessing options",
+        "Options to improve the quality of the final PDF and OCR",
+    )
+    preprocessing.add_argument(
+        '-r',
+        '--rotate-pages',
+        action='store_true',
+        help="Automatically rotate pages based on detected text orientation",
+    )
+    preprocessing.add_argument(
+        '--remove-background',
+        action='store_true',
+        help="Attempt to remove background from gray or color pages, setting it "
+        "to white ",
+    )
+    preprocessing.add_argument(
+        '-d',
+        '--deskew',
+        action='store_true',
+        help="Deskew each page before performing OCR",
+    )
+    preprocessing.add_argument(
+        '-c',
+        '--clean',
+        action='store_true',
+        help="Clean pages from scanning artifacts before performing OCR, and send "
+        "the cleaned page to OCR, but do not include the cleaned page in "
+        "the output",
+    )
+    preprocessing.add_argument(
+        '-i',
+        '--clean-final',
+        action='store_true',
+        help="Clean page as above, and incorporate the cleaned image in the final "
+        "PDF.  Might remove desired content.",
+    )
+    preprocessing.add_argument(
+        '--unpaper-args',
+        type=str,
+        default=None,
+        help="A quoted string of arguments to pass to unpaper. Requires --clean. "
+        "Example: --unpaper-args '--layout double'.",
+    )
+    preprocessing.add_argument(
+        '--oversample',
+        metavar='DPI',
+        type=numeric(int, 0, 5000),
+        default=0,
+        help="Oversample images to at least the specified DPI, to improve OCR "
+        "results slightly",
+    )
+    preprocessing.add_argument(
+        '--remove-vectors',
+        action='store_true',
+        help="EXPERIMENTAL. Mask out any vector objects in the PDF so that they "
+        "will not be included in OCR. This can eliminate false characters.",
+    )
+    preprocessing.add_argument(
+        '--threshold',
+        action='store_true',
+        help=(
+            "EXPERIMENTAL. Threshold image to 1bpp before sending it to Tesseract "
+            "for OCR. Can improve OCR quality compared to Tesseract's thresholder."
+        ),
+    )
+
+    ocrsettings = parser.add_argument_group("OCR options", "Control how OCR is applied")
+    ocrsettings.add_argument(
+        '-f',
+        '--force-ocr',
+        action='store_true',
+        help="Rasterize any text or vector objects on each page, apply OCR, and "
+        "save the rastered output (this rewrites the PDF)",
+    )
+    ocrsettings.add_argument(
+        '-s',
+        '--skip-text',
+        action='store_true',
+        help="Skip OCR on any pages that already contain text, but include the "
+        "page in final output; useful for PDFs that contain a mix of "
+        "images, text pages, and/or previously OCRed pages",
+    )
+    ocrsettings.add_argument(
+        '--redo-ocr',
+        action='store_true',
+        help="Attempt to detect and remove the hidden OCR layer from files that "
+        "were previously OCRed with OCRmyPDF or another program. Apply OCR "
+        "to text found in raster images. Existing visible text objects will "
+        "not be changed. If there is no existing OCR, OCR will be added.",
+    )
+    ocrsettings.add_argument(
+        '--skip-big',
+        type=numeric(float, 0, 5000),
+        metavar='MPixels',
+        help="Skip OCR on pages larger than the specified amount of megapixels, "
+        "but include skipped pages in final output",
+    )
+
+    optimizing = parser.add_argument_group(
+        "Optimization options", "Control how the PDF is optimized after OCR"
+    )
+    optimizing.add_argument(
+        '-O',
+        '--optimize',
+        type=int,
+        choices=range(0, 4),
+        default=1,
+        help=(
+            "Control how PDF is optimized after processing:"
+            "0 - do not optimize; "
+            "1 - do safe, lossless optimizations (default); "
+            "2 - do some lossy optimizations; "
+            "3 - do aggressive lossy optimizations (including lossy JBIG2)"
+        ),
+    )
+    optimizing.add_argument(
+        '--jpeg-quality',
+        type=numeric(int, 0, 100),
+        default=0,
+        metavar='Q',
+        help=(
+            "Adjust JPEG quality level for JPEG optimization. "
+            "100 is best quality and largest output size; "
+            "1 is lowest quality and smallest output; "
+            "0 uses the default."
+        ),
+    )
+    optimizing.add_argument(
+        '--jpg-quality',
+        type=numeric(int, 0, 100),
+        default=0,
+        metavar='Q',
+        dest='jpeg_quality',
+        help=argparse.SUPPRESS,  # Alias for --jpeg-quality
+    )
+    optimizing.add_argument(
+        '--png-quality',
+        type=numeric(int, 0, 100),
+        default=0,
+        metavar='Q',
+        help=(
+            "Adjust PNG quality level to use when quantizing PNGs. "
+            "Values have same meaning as with --jpeg-quality"
+        ),
+    )
+    optimizing.add_argument(
+        '--jbig2-lossy',
+        action='store_true',
+        help=(
+            "Enable JBIG2 lossy mode (better compression, not suitable for some "
+            "use cases - see documentation)."
+        ),
+    )
+    optimizing.add_argument(
+        '--jbig2-page-group-size',
+        type=numeric(int, 1, 10000),
+        default=0,
+        metavar='N',
+        # Adjust number of pages to consider at once for JBIG2 compression
+        help=argparse.SUPPRESS,
+    )
+
+    advanced = parser.add_argument_group(
+        "Advanced", "Advanced options to control OCRmyPDF"
+    )
+    advanced.add_argument(
+        '--pages',
+        type=str,
+        help=(
+            "Limit OCR to the specified pages (ranges or comma separated), "
+            "skipping others"
+        ),
+    )
+    advanced.add_argument(
+        '--max-image-mpixels',
+        action='store',
+        type=numeric(float, 0),
+        metavar='MPixels',
+        help="Set maximum number of pixels to unpack before treating an image as a "
+        "decompression bomb",
+        default=128.0,
+    )
+    advanced.add_argument(
+        '--pdf-renderer',
+        choices=['auto', 'hocr', 'sandwich'],
+        default='auto',
+        help="Choose OCR PDF renderer - the default option is to let OCRmyPDF "
+        "choose.  See documentation for discussion.",
+    )
+    advanced.add_argument(
+        '--rotate-pages-threshold',
+        default=14.0,
+        type=numeric(float, 0, 1000),
+        metavar='CONFIDENCE',
+        help="Only rotate pages when confidence is above this value (arbitrary "
+        "units reported by tesseract)",
+    )
+    advanced.add_argument(
+        '--pdfa-image-compression',
+        choices=['auto', 'jpeg', 'lossless'],
+        default='auto',
+        help="Specify how to compress images in the output PDF/A. 'auto' lets "
+        "OCRmyPDF decide.  'jpeg' changes all grayscale and color images to "
+        "JPEG compression.  'lossless' uses PNG-style lossless compression "
+        "for all images.  Monochrome images are always compressed using a "
+        "lossless codec.  Compression settings "
+        "are applied to all pages, including those for which OCR was "
+        "skipped.  Not supported for --output-type=pdf ; that setting "
+        "preserves the original compression of all images.",
+    )
+    advanced.add_argument(
+        '--fast-web-view',
+        type=numeric(float, 0),
+        default=1.0,
+        metavar="MEGABYTES",
+        help="If the size of file is more than this threshold (in MB), then "
+        "linearize the PDF for fast web viewing. This allows the PDF to be "
+        "displayed before it is fully downloaded in web browsers, but increases "
+        "the space required slightly. By default we skip this for small files "
+        "which do not benefit. If the threshold is 0 it will be apply to all files. "
+        "Set the threshold very high to disable.",
+    )
+    advanced.add_argument(
+        '--plugin',
+        dest='plugins',
+        action='append',
+        default=[],
+        help="Name of plugin to import. Argument may be issued multiple times to "
+        "import multiple plugins. Plugins may be specified as module names in "
+        "Python syntax, provided they are installed in the same Python (virtual) "
+        "environment as ocrmypdf; or you may give the path to the Python file that "
+        "contains the plugin. Plugins must conform to the specification in the "
+        "OCRmyPDF documentation.",
+    )
+
+    debugging = parser.add_argument_group(
+        "Debugging", "Arguments to help with troubleshooting and debugging"
+    )
+    debugging.add_argument(
+        '-k',
+        '--keep-temporary-files',
+        action='store_true',
+        help="Keep temporary files (helpful for debugging)",
+    )
+    return parser
+
+
+plugins_only_parser = ArgumentParser(
+    prog=_PROGRAM_NAME, fromfile_prefix_chars='@', add_help=False, allow_abbrev=False
 )
-parser.add_argument(
-    'output_file',
-    metavar="output_pdf",
-    help="Output searchable PDF file (or '-' to write to standard output). "
-    "Existing files will be ovewritten. If same as input file, the "
-    "input file will be updated only if processing is successful.",
-)
-parser.add_argument(
-    '-l',
-    '--language',
+plugins_only_parser.add_argument(
+    '--plugin',
+    dest='plugins',
    action='append',
-    help="Language(s) of the file to be OCRed (see tesseract --list-langs for "
-    "all language packs installed in your system). Use -l eng+deu for "
-    "multiple languages.",
-)
-parser.add_argument(
-    '--image-dpi',
-    metavar='DPI',
-    type=int,
-    help="For input image instead of PDF, use this DPI instead of file's.",
-)
-parser.add_argument(
-    '--output-type',
-    choices=['pdfa', 'pdf', 'pdfa-1', 'pdfa-2', 'pdfa-3'],
-    default='pdfa',
-    help="Choose output type. 'pdfa' creates a PDF/A-2b compliant file for "
-    "long term archiving (default, recommended) but may not suitable "
-    "for users who want their file altered as little as possible. 'pdfa' "
-    "also has problems with full Unicode text. 'pdf' attempts to "
-    "preserve file contents as much as possible. 'pdf-a1' creates a "
-    "PDF/A1-b file. 'pdf-a2' is equivalent to 'pdfa'. 'pdf-a3' creates a "
-    "PDF/A3-b file.",
-)
-
-# Use null string '\0' as sentinel to indicate the user supplied no argument,
-# since that is the only invalid character for filepaths on all platforms
-# bool('\0') is True in Python
-parser.add_argument(
-    '--sidecar',
-    nargs='?',
-    const='\0',
-    default=None,
-    metavar='FILE',
-    help="Generate sidecar text files that contain the same text recognized "
-    "by Tesseract. This may be useful for building a OCR text database. "
-    "If FILE is omitted, the sidecar file be named {output_file}.txt "
-    "If FILE is set to '-', the sidecar is written to stdout (a "
-    "convenient way to preview OCR quality). The output file and sidecar "
-    "may not both use stdout at the same time.",
-)
-
-parser.add_argument(
-    '--version',
-    action='version',
-    version=_VERSION,
-    help="Print program version and exit",
-)
-
-jobcontrol = parser.add_argument_group("Job control options")
-jobcontrol.add_argument(
-    '-j',
-    '--jobs',
-    metavar='N',
-    type=numeric(int, 0, 256),
-    help="Use up to N CPU cores simultaneously (default: use all).",
-)
-jobcontrol.add_argument(
-    '-q', '--quiet', action='store_true', help="Suppress INFO messages"
-)
-jobcontrol.add_argument(
-    '-v',
-    '--verbose',
-    type=numeric(int, 0, 2),
-    default=0,
-    const=1,
-    nargs='?',
-    help="Print more verbose messages for each additional verbose level. Use "
-    "`-v 1` typically for much more detailed logging. Higher numbers "
-    "are probably only useful in debugging.",
-)
-jobcontrol.add_argument(
-    '--no-progress-bar',
-    action='store_false',
-    dest='progress_bar',
-    help=argparse.SUPPRESS,
-)
-jobcontrol.add_argument('--use-threads', action='store_true', help=argparse.SUPPRESS)
-
-metadata = parser.add_argument_group(
-    "Metadata options",
-    "Set output PDF/A metadata (default: copy input document's metadata)",
-)
-metadata.add_argument(
-    '--title', type=str, help="Set document title (place multiple words in quotes)"
-)
-metadata.add_argument('--author', type=str, help="Set document author")
-metadata.add_argument('--subject', type=str, help="Set document subject description")
-metadata.add_argument('--keywords', type=str, help="Set document keywords")
-
-preprocessing = parser.add_argument_group(
-    "Image preprocessing options",
-    "Options to improve the quality of the final PDF and OCR",
-)
-preprocessing.add_argument(
-    '-r',
-    '--rotate-pages',
-    action='store_true',
-    help="Automatically rotate pages based on detected text orientation",
-)
-preprocessing.add_argument(
-    '--remove-background',
-    action='store_true',
-    help="Attempt to remove background from gray or color pages, setting it "
-    "to white ",
-)
-preprocessing.add_argument(
-    '-d', '--deskew', action='store_true', help="Deskew each page before performing OCR"
-)
-preprocessing.add_argument(
-    '-c',
-    '--clean',
-    action='store_true',
-    help="Clean pages from scanning artifacts before performing OCR, and send "
-    "the cleaned page to OCR, but do not include the cleaned page in "
-    "the output",
-)
-preprocessing.add_argument(
-    '-i',
-    '--clean-final',
-    action='store_true',
-    help="Clean page as above, and incorporate the cleaned image in the final "
-    "PDF.  Might remove desired content.",
-)
-preprocessing.add_argument(
-    '--unpaper-args',
-    type=str,
-    default=None,
-    help="A quoted string of arguments to pass to unpaper. Requires --clean. "
-    "Example: --unpaper-args '--layout double'.",
-)
-preprocessing.add_argument(
-    '--oversample',
-    metavar='DPI',
-    type=numeric(int, 0, 5000),
-    default=0,
-    help="Oversample images to at least the specified DPI, to improve OCR "
-    "results slightly",
-)
-preprocessing.add_argument(
-    '--remove-vectors',
-    action='store_true',
-    help="EXPERIMENTAL. Mask out any vector objects in the PDF so that they "
-    "will not be included in OCR. This can eliminate false characters.",
-)
-preprocessing.add_argument(
-    '--threshold',
-    action='store_true',
-    help="EXPERIMENTAL. Threshold image to 1bpp before sending it to Tesseract for OCR. Can "
-    "improve OCR quality compared to Tesseract's thresholder.",
-)
-
-ocrsettings = parser.add_argument_group("OCR options", "Control how OCR is applied")
-ocrsettings.add_argument(
-    '-f',
-    '--force-ocr',
-    action='store_true',
-    help="Rasterize any text or vector objects on each page, apply OCR, and "
-    "save the rastered output (this rewrites the PDF)",
-)
-ocrsettings.add_argument(
-    '-s',
-    '--skip-text',
-    action='store_true',
-    help="Skip OCR on any pages that already contain text, but include the "
-    "page in final output; useful for PDFs that contain a mix of "
-    "images, text pages, and/or previously OCRed pages",
-)
-ocrsettings.add_argument(
-    '--redo-ocr',
-    action='store_true',
-    help="Attempt to detect and remove the hidden OCR layer from files that "
-    "were previously OCRed with OCRmyPDF or another program. Apply OCR "
-    "to text found in raster images. Existing visible text objects will "
-    "not be changed. If there is no existing OCR, OCR will be added.",
-)
-ocrsettings.add_argument(
-    '--skip-big',
-    type=numeric(float, 0, 5000),
-    metavar='MPixels',
-    help="Skip OCR on pages larger than the specified amount of megapixels, "
-    "but include skipped pages in final output",
-)
-
-optimizing = parser.add_argument_group(
-    "Optimization options", "Control how the PDF is optimized after OCR"
-)
-optimizing.add_argument(
-    '-O',
-    '--optimize',
-    type=int,
-    choices=range(0, 4),
-    default=1,
-    help=(
-        "Control how PDF is optimized after processing:"
-        "0 - do not optimize; "
-        "1 - do safe, lossless optimizations (default); "
-        "2 - do some lossy optimizations; "
-        "3 - do aggressive lossy optimizations (including lossy JBIG2)"
-    ),
-)
-optimizing.add_argument(
-    '--jpeg-quality',
-    type=numeric(int, 0, 100),
-    default=0,
-    metavar='Q',
-    help=(
-        "Adjust JPEG quality level for JPEG optimization. "
-        "100 is best quality and largest output size; "
-        "1 is lowest quality and smallest output; "
-        "0 uses the default."
-    ),
-)
-optimizing.add_argument(
-    '--jpg-quality',
-    type=numeric(int, 0, 100),
-    default=0,
-    metavar='Q',
-    dest='jpeg_quality',
-    help=argparse.SUPPRESS,  # Alias for --jpeg-quality
-)
-optimizing.add_argument(
-    '--png-quality',
-    type=numeric(int, 0, 100),
-    default=0,
-    metavar='Q',
-    help=(
-        "Adjust PNG quality level to use when quantizing PNGs. "
-        "Values have same meaning as with --jpeg-quality"
-    ),
-)
-optimizing.add_argument(
-    '--jbig2-lossy',
-    action='store_true',
-    help=(
-        "Enable JBIG2 lossy mode (better compression, not suitable for some "
-        "use cases - see documentation)."
-    ),
-)
-optimizing.add_argument(
-    '--jbig2-page-group-size',
-    type=numeric(int, 1, 10000),
-    default=0,
-    metavar='N',
-    # Adjust number of pages to consider at once for JBIG2 compression
-    help=argparse.SUPPRESS,
-)
-
-advanced = parser.add_argument_group(
-    "Advanced", "Advanced options to control Tesseract's OCR behavior"
-)
-advanced.add_argument(
-    '--pages',
-    type=str,
-    help="Limit OCR to the specified pages (ranges or comma separated), skipping others",
-)
-advanced.add_argument(
-    '--max-image-mpixels',
-    action='store',
-    type=numeric(float, 0),
-    metavar='MPixels',
-    help="Set maximum number of pixels to unpack before treating an image as a "
-    "decompression bomb",
-    default=128.0,
-)
-advanced.add_argument(
-    '--tesseract-config',
-    action='append',
-    metavar='CFG',
    default=[],
-    help="Additional Tesseract configuration files -- see documentation",
+    help="Name of plugin to import.",
 )
-advanced.add_argument(
-    '--tesseract-pagesegmode',
-    action='store',
-    type=int,
-    metavar='PSM',
-    choices=range(0, 14),
-    help="Set Tesseract page segmentation mode (see tesseract --help)",
-)
-advanced.add_argument(
-    '--tesseract-oem',
-    action='store',
-    type=int,
-    metavar='MODE',
-    choices=range(0, 4),
-    help=(
-        "Set Tesseract 4.0 OCR engine mode: "
-        "0 - original Tesseract only; "
-        "1 - neural nets LSTM only; "
-        "2 - Tesseract + LSTM; "
-        "3 - default."
-    ),
-)
-advanced.add_argument(
-    '--pdf-renderer',
-    choices=['auto', 'hocr', 'sandwich'],
-    default='auto',
-    help="Choose OCR PDF renderer - the default option is to let OCRmyPDF "
-    "choose.  See documentation for discussion.",
-)
-advanced.add_argument(
-    '--tesseract-timeout',
-    default=180.0,
-    type=numeric(float, 0),
-    metavar='SECONDS',
-    help='Give up on OCR after the timeout, but copy the preprocessed page '
-    'into the final output',
-)
-advanced.add_argument(
-    '--rotate-pages-threshold',
-    default=14.0,
-    type=numeric(float, 0, 1000),
-    metavar='CONFIDENCE',
-    help="Only rotate pages when confidence is above this value (arbitrary "
-    "units reported by tesseract)",
-)
-advanced.add_argument(
-    '--pdfa-image-compression',
-    choices=['auto', 'jpeg', 'lossless'],
-    default='auto',
-    help="Specify how to compress images in the output PDF/A. 'auto' lets "
-    "OCRmyPDF decide.  'jpeg' changes all grayscale and color images to "
-    "JPEG compression.  'lossless' uses PNG-style lossless compression "
-    "for all images.  Monochrome images are always compressed using a "
-    "lossless codec.  Compression settings "
-    "are applied to all pages, including those for which OCR was "
-    "skipped.  Not supported for --output-type=pdf ; that setting "
-    "preserves the original compression of all images.",
-)
-advanced.add_argument(
-    '--user-words',
-    metavar='FILE',
-    help="Specify the location of the Tesseract user words file. This is a "
-    "list of words Tesseract should consider while performing OCR in "
-    "addition to its standard language dictionaries. This can improve "
-    "OCR quality especially for specialized and technical documents.",
-)
-advanced.add_argument(
-    '--user-patterns',
-    metavar='FILE',
-    help="Specify the location of the Tesseract user patterns file.",
-)
-advanced.add_argument(
-    '--fast-web-view',
-    type=numeric(float, 0),
-    default=1.0,
-    metavar="MEGABYTES",
-    help="If the size of file is more than this threshold (in MB), then "
-    "linearize the PDF for fast web viewing. This allows the PDF to be "
-    "displayed before it is fully downloaded in web browsers, but increases "
-    "the space required slightly. By default we skip this for small files "
-    "which do not benefit. If the threshold is 0 it will be apply to all files. "
-    "Set the threshold very high to disable.",
-)
-
-debugging = parser.add_argument_group(
-    "Debugging", "Arguments to help with troubleshooting and debugging"
-)
-debugging.add_argument(
-    '-k',
-    '--keep-temporary-files',
-    action='store_true',
-    help="Keep temporary files (helpful for debugging)",
-)
-debugging.add_argument('--tesseract-env', type=str, help=argparse.SUPPRESS)
@@ -1,19 +1,8 @@
 # © 2016 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.


 from enum import IntEnum
@@ -1,61 +0,0 @@
-# © 2017 James R. Barlow: github.com/jbarlow83
-#
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
-
-"""Interface to qpdf executable"""
-
-from io import StringIO
-
-import pikepdf
-
-
-def version():
-    return pikepdf.__libqpdf_version__
-
-
-def check(input_file, log=None):
-    pdf = None
-    try:
-        pdf = pikepdf.open(input_file)
-    except pikepdf.PdfError as e:
-        if log:
-            log.error(e)
-        return False
-    else:
-        messages = pdf.check()
-        for msg in messages:
-            if 'error' in msg.lower():
-                log.error(msg)
-            else:
-                log.warning(msg)
-
-        sio = StringIO()
-        linearize = None
-        try:
-            pdf.check_linearization(sio)
-        except RuntimeError:
-            pass
-        else:
-            linearize = sio.getvalue()
-            if linearize:
-                log.warning(linearize)
-
-        if not messages and not linearize:
-            return True
-        return False
-    finally:
-        if pdf:
-            pdf.close()
@@ -1,42 +1,67 @@
 # © 2016 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import logging
 import multiprocessing
 import os
 import shutil
 import warnings
+from collections import namedtuple
 from collections.abc import Iterable
 from contextlib import suppress
 from functools import wraps
+from io import StringIO
+from math import isclose
 from pathlib import Path
+from typing import Any, Sequence, TypeVar
+
+import pikepdf

 log = logging.getLogger(__name__)


-def safe_symlink(input_file, soft_link_name, *args, **kwargs):
+class Resolution(namedtuple('Resolution', ('x', 'y'))):
+    """The number of pixels per inch in each 2D direction."""
+
+    __slots__ = ()
+
+    def round(self, ndigits: int):
+        return Resolution(round(self.x, ndigits), round(self.y, ndigits))
+
+    def to_int(self):
+        return Resolution(int(round(self.x)), int(round(self.y)))
+
+    @property
+    def is_square(self) -> bool:
+        return isclose(self.x, self.y, rel_tol=1e-3)
+
+    def take_max(self, vals, yvals=None):
+        if yvals is not None:
+            return Resolution(max(self.x, *vals), max(self.y, *yvals))
+        max_x, max_y = self.x, self.y
+        for x, y in vals:
+            max_x = max(x, max_x)
+            max_y = max(y, max_y)
+        return Resolution(max_x, max_y)
+
+    def flip_axis(self):
+        return Resolution(self.y, self.x)
+
+    def __str__(self):
+        return f"{self.x:f}x{self.y:f}"
+
+    def __repr__(self):
+        return f"Resolution({self.x}x{self.y} dpi)"
+
+
+def safe_symlink(input_file: os.PathLike, soft_link_name: os.PathLike):
    """
    Helper function: relinks soft symbolic link if necessary
    """
-    if len(args) == 1 and isinstance(args[0], logging.Logger):
-        log.warning("Deprecated: safe_symlink(,log)")
-    if 'log' in kwargs:
-        log.warning('Deprecated: safe_symlink(...log=)')
-
    input_file = os.fspath(input_file)
    soft_link_name = os.fspath(soft_link_name)

@@ -72,21 +97,30 @@ def safe_symlink(input_file, soft_link_name, *args, **kwargs):
    os.symlink(os.path.abspath(input_file), soft_link_name)


-def is_iterable_notstr(thing):
+def samefile(f1: os.PathLike, f2: os.PathLike):
+    if os.name == 'nt':
+        return f1 == f2
+    else:
+        return os.path.samefile(f1, f2)
+
+
+def is_iterable_notstr(thing: Any) -> bool:
+    """Is this is an iterable type, other than a string?"""
    return isinstance(thing, Iterable) and not isinstance(thing, str)


-def monotonic(L):
+def monotonic(L: Sequence) -> bool:
    """Does list increase monotonically?"""
    return all(b > a for a, b in zip(L, L[1:]))


-def page_number(input_file):
+def page_number(input_file: os.PathLike) -> int:
    """Get one-based page number implied by filename (000002.pdf -> 2)"""
    return int(os.path.basename(os.fspath(input_file))[0:6])


-def available_cpu_count():
+def available_cpu_count() -> int:
+    """Returns number of CPUs in the system."""
    try:
        return multiprocessing.cpu_count()
    except NotImplementedError:
@@ -97,7 +131,7 @@ def available_cpu_count():
    return 1


-def is_file_writable(test_file):
+def is_file_writable(test_file: os.PathLike) -> bool:
    """Intentionally racy test if target is writable.

    We intend to write to the output file if and only if we succeed and
@@ -105,11 +139,7 @@ def is_file_writable(test_file):
    the location is writable.
    """
    try:
-        if not isinstance(test_file, Path):
-            p = Path(test_file)
-        else:
-            p = test_file
-
+        p = Path(test_file)
        if p.is_symlink():
            p = p.resolve(strict=False)

@@ -136,6 +166,60 @@ def is_file_writable(test_file):
        return False


+def check_pdf(input_file: Path) -> bool:
+    """Check if a PDF complies with the PDF specification.
+
+    Checks for proper formatting and proper linearization.
+    """
+    pdf = None
+    try:
+        pdf = pikepdf.open(input_file)
+    except pikepdf.PdfError as e:
+        log.error(e)
+        return False
+    else:
+        messages = pdf.check()
+        for msg in messages:
+            if 'error' in msg.lower():
+                log.error(msg)
+            else:
+                log.warning(msg)
+
+        sio = StringIO()
+        linearize = None
+        try:
+            pdf.check_linearization(sio)
+        except RuntimeError:
+            pass
+        else:
+            linearize = sio.getvalue()
+            if linearize:
+                log.warning(linearize)
+
+        if not messages and not linearize:
+            return True
+        return False
+    finally:
+        if pdf:
+            pdf.close()
+
+
+T = TypeVar('T')
+
+
+def clamp(n: T, smallest: T, largest: T) -> T:
+    """Clamps the value of n to between smallest and largest."""
+    return max(smallest, min(n, largest))
+
+
+def pikepdf_enable_mmap():
+    try:
+        if pikepdf._qpdf.set_access_default_mmap(True):
+            log.debug("pikepdf mmap enabled")
+    except AttributeError:
+        log.debug("pikepdf mmap not available")
+
+
 def deprecated(func):
    """Warn that function is deprecated"""

@@ -29,11 +29,16 @@
 # SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

 import argparse
+import os
 import re
 from collections import namedtuple
+from itertools import chain
 from math import atan, cos, sin
+from pathlib import Path
+from typing import Optional, Tuple, Union
 from xml.etree import ElementTree

+from reportlab.lib.colors import black, cyan, magenta, red
 from reportlab.lib.units import inch
 from reportlab.pdfgen.canvas import Canvas

@@ -64,9 +69,9 @@ class HocrTransform:
        {'ﬀ': 'ff', 'ﬃ': 'f‌f‌i', 'ﬄ': 'f‌f‌l', 'ﬁ': 'fi', 'ﬂ': 'fl'}
    )

-    def __init__(self, hocrFileName, dpi):
+    def __init__(self, hocr_filename: Union[str, Path], dpi: float):
        self.dpi = dpi
-        self.hocr = ElementTree.parse(hocrFileName)
+        self.hocr = ElementTree.parse(os.fspath(hocr_filename))

        # if the hOCR file has a namespace, ElementTree requires its use to
        # find elements
@@ -77,7 +82,7 @@ class HocrTransform:

        # get dimension in pt (not pixel!!!!) of the OCRed image
        self.width, self.height = None, None
-        for div in self.hocr.findall(".//%sdiv[@class='ocr_page']" % (self.xmlns)):
+        for div in self.hocr.findall(self._child_xpath('div', 'ocr_page')):
            coords = self.element_coordinates(div)
            pt_coords = self.pt_from_pixel(coords)
            self.width = pt_coords.x2 - pt_coords.x1
@@ -94,7 +99,7 @@ class HocrTransform:
        """
        if self.hocr is None:
            return ''
-        body = self.hocr.find(".//%sbody" % (self.xmlns))
+        body = self.hocr.find(self._child_xpath('body'))
        if body:
            return self._get_element_text(body)
        else:
@@ -107,19 +112,19 @@ class HocrTransform:
        text = ''
        if element.text is not None:
            text += element.text
-        for child in element.getchildren():
+        for child in element:
            text += self._get_element_text(child)
        if element.tail is not None:
            text += element.tail
        return text

    @classmethod
-    def element_coordinates(cls, element):
+    def element_coordinates(cls, element) -> Rect:
        """
        Returns a tuple containing the coordinates of the bounding box around
        an element
        """
-        out = (0, 0, 0, 0)
+        out = Rect._make(0 for _ in range(4))
        if 'title' in element.attrib:
            matches = cls.box_pattern.search(element.attrib['title'])
            if matches:
@@ -128,7 +133,7 @@ class HocrTransform:
        return out

    @classmethod
-    def baseline(cls, element):
+    def baseline(cls, element) -> Tuple[float, float]:
        """
        Returns a tuple containing the baseline slope and intercept.
        """
@@ -136,32 +141,43 @@ class HocrTransform:
            matches = cls.baseline_pattern.search(element.attrib['title'])
            if matches:
                return float(matches.group(1)), int(matches.group(2))
-        return (0, 0)
+        return (0.0, 0.0)

-    def pt_from_pixel(self, pxl):
+    def pt_from_pixel(self, pxl) -> Rect:
        """
        Returns the quantity in PDF units (pt) given quantity in pixels
        """
        return Rect._make((c / self.dpi * inch) for c in pxl)

+    def _child_xpath(self, html_tag, html_class=None):
+        xpath = f".//{self.xmlns}{html_tag}"
+        if html_class:
+            xpath += f"[@class='{html_class}']"
+        return xpath
+
    @classmethod
-    def replace_unsupported_chars(cls, s):
+    def replace_unsupported_chars(cls, s: str) -> str:
        """
        Given an input string, returns the corresponding string that:
-        - is available in the helvetica facetype
-        - does not contain any ligature (to allow easy search in the PDF file)
+        * is available in the Helvetica facetype
+        * does not contain any ligature (to allow easy search in the PDF file)
        """
        return s.translate(cls.ligatures)

+    def topdown_position(self, element):
+        pxl_line_coords = self.element_coordinates(element)
+        line_box = self.pt_from_pixel(pxl_line_coords)
+        return -line_box.y2
+
    def to_pdf(
        self,
-        outFileName,
-        imageFileName=None,
-        showBoundingboxes=False,
-        fontname="Helvetica",
-        invisibleText=False,
-        interwordSpaces=False,
-    ):
+        out_filename: Path,
+        image_filename: Optional[Path] = None,
+        show_bounding_boxes: bool = False,
+        fontname: str = "Helvetica",
+        invisible_text: bool = False,
+        interword_spaces: bool = False,
+    ) -> None:
        """
        Creates a PDF file with an image superimposed on top of the text.
        Text is positioned according to the bounding box of the lines in
@@ -169,19 +185,36 @@ class HocrTransform:
        The image need not be identical to the image used to create the hOCR
        file.
        It can have a lower resolution, different color mode, etc.
+
+        Arguments:
+            out_filename: Path of PDF to write.
+            image_filename: Image to use for this file. If omitted, the OCR text
+                is shown.
+            show_bounding_boxes: Show bounding boxes around various text regions,
+                for debugging.
+            fontname: Name of font to use.
+            invisible_text: If True, text is rendered invisible so that is
+                selectable but never drawn. If False, text is visible and may
+                be seen if the image is skipped or deleted in Acrobat.
+            interword_spaces: If True, insert spaces between words rather than
+                drawing each word without spaces. Generally this improves text
+                extraction.
        """
        # create the PDF file
        # page size in points (1/72 in.)
-        pdf = Canvas(outFileName, pagesize=(self.width, self.height), pageCompression=1)
+        pdf = Canvas(
+            os.fspath(out_filename),
+            pagesize=(self.width, self.height),
+            pageCompression=1,
+        )

        # draw bounding box for each paragraph
        # light blue for bounding box of paragraph
-        pdf.setStrokeColorRGB(0, 1, 1)
+        pdf.setStrokeColor(cyan)
        # light blue for bounding box of paragraph
-        pdf.setFillColorRGB(0, 1, 1)
+        pdf.setFillColor(cyan)
        pdf.setLineWidth(0)  # no line for bounding box
-        for elem in self.hocr.findall(".//%sp[@class='%s']" % (self.xmlns, "ocr_par")):
-
+        for elem in self.hocr.iterfind(self._child_xpath('p', 'ocr_par')):
            elemtxt = self._get_element_text(elem).rstrip()
            if len(elemtxt) == 0:
                continue
@@ -190,14 +223,19 @@ class HocrTransform:
            pt = self.pt_from_pixel(pxl_coords)

            # draw the bbox border
-            if showBoundingboxes:  # pragma: no cover
+            if show_bounding_boxes:  # pragma: no cover
                pdf.rect(
                    pt.x1, self.height - pt.y2, pt.x2 - pt.x1, pt.y2 - pt.y1, fill=1
                )

        found_lines = False
-        for line in self.hocr.findall(
-            ".//%sspan[@class='%s']" % (self.xmlns, "ocr_line")
+        for line in sorted(
+            chain(
+                self.hocr.iterfind(self._child_xpath('span', 'ocr_header')),
+                self.hocr.iterfind(self._child_xpath('span', 'ocr_line')),
+                self.hocr.iterfind(self._child_xpath('span', 'ocr_textfloat')),
+            ),
+            key=self.topdown_position,
        ):
            found_lines = True
            self._do_line(
@@ -205,26 +243,28 @@ class HocrTransform:
                line,
                "ocrx_word",
                fontname,
-                invisibleText,
-                interwordSpaces,
-                showBoundingboxes,
+                invisible_text,
+                interword_spaces,
+                show_bounding_boxes,
            )

        if not found_lines:
            # Tesseract did not report any lines (just words)
-            root = self.hocr.find(".//%sdiv[@class='%s']" % (self.xmlns, "ocr_page"))
+            root = self.hocr.find(self._child_xpath('div', 'ocr_page'))
            self._do_line(
                pdf,
                root,
                "ocrx_word",
                fontname,
-                invisibleText,
-                interwordSpaces,
-                showBoundingboxes,
+                invisible_text,
+                interword_spaces,
+                show_bounding_boxes,
            )
        # put the image on the page, scaled to fill the page
-        if imageFileName is not None:
-            pdf.drawImage(imageFileName, 0, 0, width=self.width, height=self.height)
+        if image_filename is not None:
+            pdf.drawImage(
+                os.fspath(image_filename), 0, 0, width=self.width, height=self.height
+            )

        # finish up the page and save it
        pdf.showPage()
@@ -236,13 +276,13 @@ class HocrTransform:

    def _do_line(
        self,
-        pdf,
+        pdf: Canvas,
        line,
-        elemclass,
-        fontname,
-        invisibleText,
-        interwordSpaces,
-        showBoundingboxes,
+        elemclass: str,
+        fontname: str,
+        invisible_text: bool,
+        interword_spaces: bool,
+        show_bounding_boxes: bool,
    ):
        pxl_line_coords = self.element_coordinates(line)
        line_box = self.pt_from_pixel(pxl_line_coords)
@@ -262,17 +302,17 @@ class HocrTransform:
        # on a sloped baseline and the edge of the bounding box.
        fontsize = (line_height - abs(intercept)) / cos_a
        text.setFont(fontname, fontsize)
-        if invisibleText:
+        if invisible_text:
            text.setTextRenderMode(3)  # Invisible (indicates OCR text)

        # Intercept is normally negative, so this places it above the bottom
        # of the line box
        baseline_y2 = self.height - (line_box.y2 + intercept)

-        if showBoundingboxes:  # pragma: no cover
+        if show_bounding_boxes:  # pragma: no cover
            # draw the baseline in magenta, dashed
            pdf.setDash()
-            pdf.setStrokeColorRGB(0.95, 0.65, 0.95)
+            pdf.setStrokeColor(magenta)
            pdf.setLineWidth(0.5)
            # negate slope because it is defined as a rise/run in pixel
            # coordinates and page coordinates have the y axis flipped
@@ -284,12 +324,12 @@ class HocrTransform:
            )
            # light green for bounding box of word/line
            pdf.setDash(6, 3)
-            pdf.setStrokeColorRGB(1, 0, 0)
+            pdf.setStrokeColor(red)

        text.setTextTransform(cos_a, -sin_a, sin_a, cos_a, line_box.x1, baseline_y2)
-        pdf.setFillColorRGB(0, 0, 0)  # text in black
+        pdf.setFillColor(black)  # text in black

-        elements = line.findall(".//%sspan[@class='%s']" % (self.xmlns, elemclass))
+        elements = line.findall(self._child_xpath('span', elemclass))
        for elem in elements:
            elemtxt = self._get_element_text(elem).strip()
            elemtxt = self.replace_unsupported_chars(elemtxt)
@@ -298,7 +338,7 @@ class HocrTransform:

            pxl_coords = self.element_coordinates(elem)
            box = self.pt_from_pixel(pxl_coords)
-            if interwordSpaces:
+            if interword_spaces:
                # if  `--interword-spaces` is true, append a space
                # to the end of each text element to allow simpler PDF viewers
                # such as PDF.js to better recognize words in search and copy
@@ -318,7 +358,7 @@ class HocrTransform:
            font_width = pdf.stringWidth(elemtxt, fontname, fontsize)

            # draw the bbox border
-            if showBoundingboxes:  # pragma: no cover
+            if show_bounding_boxes:  # pragma: no cover
                pdf.rect(
                    box.x1, self.height - line_box.y2, box_width, line_height, fill=0
                )
@@ -385,5 +425,5 @@ if __name__ == "__main__":
        args.outputfile,
        args.image,
        args.boundingboxes,
-        interwordSpaces=args.interword_spaces,
+        interword_spaces=args.interword_spaces,
    )
@@ -3,20 +3,10 @@
 #
 # © 2013-16: jbarlow83 from Github (https://github.com/jbarlow83)
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
 #
 # Python FFI wrapper for Leptonica library

@@ -24,18 +14,20 @@ import argparse
 import logging
 import os
 import sys
+import threading
 import warnings
+from collections import deque
 from collections.abc import Sequence
 from contextlib import suppress
 from ctypes.util import find_library
 from functools import lru_cache
-from io import BytesIO
+from io import BytesIO, UnsupportedOperation
 from os import fspath
 from tempfile import TemporaryFile

-from .exceptions import MissingDependencyError
-from .exec import shim_paths_with_program_files
-from .lib._leptonica import ffi
+from ocrmypdf.exceptions import MissingDependencyError
+from ocrmypdf.lib._leptonica import ffi
+from ocrmypdf.subprocess import shim_paths_with_program_files

 # pylint: disable=protected-access

@@ -75,7 +67,7 @@ except ffi.error as e:
    ) from e


-class _LeptonicaErrorTrap:
+class _LeptonicaErrorTrap_Redirect:
    """
    Context manager to trap errors reported by Leptonica.

@@ -90,20 +82,21 @@ class _LeptonicaErrorTrap:

    """

+    leptonica_lock = threading.Lock()
+
    def __init__(self):
        self.tmpfile = None
        self.copy_of_stderr = -1
        self.no_stderr = False

    def __enter__(self):
-        from io import UnsupportedOperation
-
        self.tmpfile = TemporaryFile()

        # Save the old stderr, and redirect stderr to temporary file
-        with suppress(AttributeError):
-            sys.stderr.flush()
+        self.leptonica_lock.acquire()
        try:
+            with suppress(AttributeError):
+                sys.stderr.flush()
            self.copy_of_stderr = os.dup(sys.stderr.fileno())
            os.dup2(self.tmpfile.fileno(), sys.stderr.fileno(), inheritable=False)
        except AttributeError:
@@ -115,7 +108,10 @@ class _LeptonicaErrorTrap:
            os.dup2(self.tmpfile.fileno(), 2, inheritable=False)
        except UnsupportedOperation:
            self.copy_of_stderr = None
-        return
+        except Exception:
+            self.leptonica_lock.release()
+            raise
+        return self

    def __exit__(self, exc_type, exc_value, traceback):
        # Restore old stderr
@@ -132,6 +128,8 @@ class _LeptonicaErrorTrap:
        self.tmpfile.seek(0)  # Cursor will be at end, so move back to beginning
        leptonica_output = self.tmpfile.read().decode(errors='replace')
        self.tmpfile.close()
+        self.leptonica_lock.release()
+
        # If there are Python errors, record them
        if exc_type:
            logger.warning(leptonica_output)
@@ -149,6 +147,62 @@ class _LeptonicaErrorTrap:
        return False


+tls = threading.local()
+tls.trap = None
+
+
+@ffi.callback("void(char *)")
+def _stderr_handler(cstr):
+    msg = ffi.string(cstr).decode(errors='replace')
+    if msg.startswith("Error"):
+        logger.error(msg)
+    elif msg.startswith("Warning"):
+        logger.warning(msg)
+    else:
+        logger.debug(msg)
+    if tls.trap is not None:
+        tls.trap.append(msg)
+    return
+
+
+class _LeptonicaErrorTrap_Queue:
+    def __init__(self):
+        self.queue = deque()
+
+    def __enter__(self):
+        self.queue.clear()
+        tls.trap = self.queue
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        tls.trap = None
+        output = ''.join(self.queue)
+        self.queue.clear()
+
+        # If there are Python errors, record them
+        if exc_type:
+            logger.warning(output)
+
+        if 'Error' in output:
+            if 'image file not found' in output:
+                raise FileNotFoundError()
+            if 'pixWrite: stream not opened' in output:
+                raise LeptonicaIOError()
+            if 'index not valid' in output:
+                raise IndexError()
+            raise LeptonicaError(output)
+        return False
+
+
+try:
+    lept.leptSetStderrHandler(_stderr_handler)
+except ffi.error:
+    # Pre-1.79 Leptonica does not have leptSetStderrHandler
+    _LeptonicaErrorTrap = _LeptonicaErrorTrap_Redirect
+else:
+    # 1.79 have this new symbol
+    _LeptonicaErrorTrap = _LeptonicaErrorTrap_Queue
+
+
 class LeptonicaError(Exception):
    pass

@@ -351,7 +405,7 @@ class Pix(LeptonicaObject):
            py_file.write(buffer)

    @classmethod
-    def frompil(self, pillow_image):
+    def frompil(cls, pillow_image):
        """Create a copy of a PIL.Image from this Pix"""
        bio = BytesIO()
        pillow_image.save(bio, format='png', compress_level=1)
@@ -363,7 +417,7 @@ class Pix(LeptonicaObject):

    def topil(self):
        """Returns a PIL.Image version of this Pix"""
-        from PIL import Image
+        from PIL import Image  # pylint: disable=import-outside-toplevel

        # Leptonica manages data in words, so it implicitly does an endian
        # swap.  Tell Pillow about this when it reads the data.
@@ -534,16 +588,7 @@ class Pix(LeptonicaObject):
            )
            return Pix(thresh_pix)

-    def crop_to_foreground(
-        self,
-        threshold=128,
-        mindist=70,
-        erasedist=30,
-        pagenum=0,
-        showmorph=0,
-        display=0,
-        pdfdir=ffi.NULL,
-    ):
+    def crop_to_foreground(self, threshold=128, mindist=70, erasedist=30, showmorph=0):
        if get_leptonica_version() < 'leptonica-1.76':
            # Leptonica 1.76 changed the API for pixFindPageForeground; we don't
            # support the old version
@@ -866,6 +911,8 @@ def get_leptonica_version():
    Caveat: Leptonica expects the caller to free this memory.  We don't,
    since that would involve binding to libc to access libc.free(),
    a pointless effort to reclaim 100 bytes of memory.
+
+    Reminder that this returns "leptonica-1.xx" or "leptonica-1.yy.0".
    """
    return ffi.string(lept.getLeptonicaVersion()).decode()

@@ -1,18 +1,8 @@
 # © 2017 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """Bindings to external libraries"""
@@ -1,20 +1,10 @@
 #!/usr/bin/env python3
 # © 2017 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 from pathlib import Path

@@ -509,6 +499,8 @@ void selDestroy ( SEL **psel );
 l_int32
 setMsgSeverity(l_int32 newsev);

+void
+leptSetStderrHandler(void (*handler)(const char *));
 """
 )

@@ -1,66 +1,84 @@
 # © 2018 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.

-import concurrent.futures
+
+import logging
 import sys
 import tempfile
 from collections import defaultdict
+from functools import partial
 from os import fspath
 from pathlib import Path
+from typing import (
+    Any,
+    Callable,
+    Dict,
+    Iterator,
+    List,
+    MutableSet,
+    NamedTuple,
+    NewType,
+    Optional,
+    Sequence,
+    Tuple,
+    Union,
+)

 import pikepdf
-from pikepdf import Dictionary, Name
+from pikepdf import Dictionary, Name, Object, Pdf, PdfImage
 from PIL import Image
 from tqdm import tqdm

-from . import leptonica
-from ._jobcontext import PDFContext
-from .exceptions import OutputFileAccessError
-from .exec import jbig2enc, pngquant
-from .helpers import safe_symlink
+from ocrmypdf import leptonica
+from ocrmypdf._concurrent import exec_progress_pool
+from ocrmypdf._exec import jbig2enc, pngquant
+from ocrmypdf._jobcontext import PdfContext
+from ocrmypdf.exceptions import OutputFileAccessError
+from ocrmypdf.helpers import safe_symlink
+
+log = logging.getLogger(__name__)

 DEFAULT_JPEG_QUALITY = 75
 DEFAULT_PNG_QUALITY = 70


-def img_name(root, xref, ext):
-    return fspath(root / f'{xref:08d}{ext}')
+Xref = NewType('Xref', int)


-def png_name(root, xref):
+class XrefExt(NamedTuple):
+    xref: Xref
+    ext: str
+
+
+def img_name(root: Path, xref: Xref, ext: str) -> Path:
+    return root / f'{xref:08d}{ext}'
+
+
+def png_name(root: Path, xref: Xref) -> Path:
    return img_name(root, xref, '.png')


-def jpg_name(root, xref):
+def jpg_name(root: Path, xref: Xref) -> Path:
    return img_name(root, xref, '.jpg')


-def tif_name(root, xref):
+def tif_name(root: Path, xref: Xref) -> Path:
    return img_name(root, xref, '.tif')


-def extract_image_filter(pike, root, log, image, xref):
+def extract_image_filter(
+    pike: Pdf, root: Path, image: Object, xref: Xref
+) -> Optional[Tuple[PdfImage, Tuple[Name, Object]]]:
    if image.Subtype != Name.Image:
        return None
    if image.Length < 100:
        log.debug("Skipping small image, xref %s", xref)
        return None

-    pim = pikepdf.PdfImage(image)
+    pim = PdfImage(image)

    if len(pim.filter_decodeparms) > 1:
        log.debug("Skipping multiply filtered, xref %s", xref)
@@ -79,30 +97,34 @@ def extract_image_filter(pike, root, log, image, xref):
    return pim, filtdp


-def extract_image_jbig2(*, pike, root, log, image, xref, options):
-    result = extract_image_filter(pike, root, log, image, xref)
+def extract_image_jbig2(
+    *, pike: pikepdf.Pdf, root: Path, image: Object, xref: Xref, options
+) -> Optional[XrefExt]:
+    result = extract_image_filter(pike, root, image, xref)
    if result is None:
        return None
    pim, filtdp = result

    if (
        pim.bits_per_component == 1
-        and filtdp != Name.JBIG2Decode
+        and filtdp[0] != Name.JBIG2Decode
        and jbig2enc.available()
    ):
        try:
-            imgname = Path(root / f'{xref:08d}')
+            imgname = root / f'{xref:08d}'
            with imgname.open('wb') as f:
                ext = pim.extract_to(stream=f)
            imgname.rename(imgname.with_suffix(ext))
        except pikepdf.UnsupportedImageTypeError:
            return None
-        return xref, ext
+        return XrefExt(xref, ext)
    return None


-def extract_image_generic(*, pike, root, log, image, xref, options):
-    result = extract_image_filter(pike, root, log, image, xref)
+def extract_image_generic(
+    *, pike: Pdf, root: Path, image: PdfImage, xref: Xref, options
+) -> Optional[XrefExt]:
+    result = extract_image_filter(pike, root, image, xref)
    if result is None:
        return None
    pim, filtdp = result
@@ -134,13 +156,13 @@ def extract_image_generic(*, pike, root, log, image, xref, options):
        #     with Image.open(stream) as im:
        #         im.save(jpg_name(root, xref), icc_profile=iccbytes)
        try:
-            imgname = Path(root / f'{xref:08d}')
+            imgname = root / f'{xref:08d}'
            with imgname.open('wb') as f:
                ext = pim.extract_to(stream=f)
            imgname.rename(imgname.with_suffix(ext))
        except pikepdf.UnsupportedImageTypeError:
            return None
-        return xref, ext
+        return XrefExt(xref, ext)
    elif (
        pim.indexed
        and pim.colorspace in pim.SIMPLE_COLORSPACES
@@ -149,12 +171,12 @@ def extract_image_generic(*, pike, root, log, image, xref, options):
        # Try to improve on indexed images - these are far from low hanging
        # fruit in most cases
        pim.as_pil_image().save(png_name(root, xref))
-        return xref, '.png'
+        return XrefExt(xref, '.png')
    elif not pim.indexed and pim.colorspace in pim.SIMPLE_COLORSPACES:
        # An optimization opportunity here, not currently taken, is directly
        # generating a PNG from compressed data
        pim.as_pil_image().save(png_name(root, xref))
-        return xref, '.png'
+        return XrefExt(xref, '.png')
    elif (
        not pim.indexed
        and pim.colorspace == Name.ICCBased
@@ -165,12 +187,14 @@ def extract_image_generic(*, pike, root, log, image, xref, options):
        # paying any attention to the ICC profile, provided we're not doing
        # lossy JBIG2
        pim.as_pil_image().save(png_name(root, xref))
-        return xref, '.png'
+        return XrefExt(xref, '.png')

    return None


-def extract_images(pike, root, log, options, extract_fn):
+def extract_images(
+    pike: Pdf, root: Path, options, extract_fn: Callable[..., Optional[XrefExt]],
+) -> Iterator[Tuple[int, XrefExt]]:
    """Extract image using extract_fn

    Enumerate images on each page, lookup their xref/ID number in the PDF.
@@ -186,8 +210,8 @@ def extract_images(pike, root, log, options, extract_fn):
    extension. extract_fn must also extract the file it finds interesting.
    """

-    include_xrefs = set()
-    exclude_xrefs = set()
+    include_xrefs: MutableSet[Xref] = set()
+    exclude_xrefs: MutableSet[Xref] = set()
    pageno_for_xref = {}
    errors = 0
    for pageno, page in enumerate(pike.pages):
@@ -198,10 +222,10 @@ def extract_images(pike, root, log, options, extract_fn):
        for _imname, image in dict(xobjs).items():
            if image.objgen[1] != 0:
                continue  # Ignore images in an incremental PDF
-            xref = image.objgen[0]
+            xref = Xref(image.objgen[0])
            if hasattr(image, 'SMask'):
                # Ignore soft masks
-                smask_xref = image.SMask.objgen[0]
+                smask_xref = Xref(image.SMask.objgen[0])
                exclude_xrefs.add(smask_xref)
            include_xrefs.add(xref)
            if xref not in pageno_for_xref:
@@ -212,41 +236,41 @@ def extract_images(pike, root, log, options, extract_fn):
        image = pike.get_object((xref, 0))
        try:
            result = extract_fn(
-                pike=pike, root=root, log=log, image=image, xref=xref, options=options
+                pike=pike, root=root, image=image, xref=xref, options=options
            )
-        except Exception as e:
+        except Exception as e:  # pylint: disable=broad-except
            log.debug("Image xref %s, error %s", xref, repr(e))
            errors += 1
        else:
            if result:
                _, ext = result
-                yield pageno_for_xref[xref], xref, ext
+                yield pageno_for_xref[xref], XrefExt(xref, ext)


-def extract_images_generic(pike, root, log, options):
+def extract_images_generic(
+    pike: Pdf, root: Path, options
+) -> Tuple[List[Xref], List[Xref]]:
    """Extract any >=2bpp image we think we can improve"""

    jpegs = []
    pngs = []
-    for _, xref, ext in extract_images(pike, root, log, options, extract_image_generic):
-        log.debug('xref = %s ext = %s', xref, ext)
-        if ext == '.png':
-            pngs.append(xref)
-        elif ext == '.jpg':
-            jpegs.append(xref)
+    for _, xref_ext in extract_images(pike, root, options, extract_image_generic):
+        log.debug('%s', xref_ext)
+        if xref_ext.ext == '.png':
+            pngs.append(xref_ext.xref)
+        elif xref_ext.ext == '.jpg':
+            jpegs.append(xref_ext.xref)
    log.debug("Optimizable images: JPEGs: %s PNGs: %s", len(jpegs), len(pngs))
    return jpegs, pngs


-def extract_images_jbig2(pike, root, log, options):
+def extract_images_jbig2(pike: Pdf, root: Path, options) -> Dict[int, List[XrefExt]]:
    """Extract any bitonal image that we think we can improve as JBIG2"""

    jbig2_groups = defaultdict(list)
-    for pageno, xref, ext in extract_images(
-        pike, root, log, options, extract_image_jbig2
-    ):
+    for pageno, xref_ext in extract_images(pike, root, options, extract_image_jbig2):
        group = pageno // options.jbig2_page_group_size
-        jbig2_groups[group].append((xref, ext))
+        jbig2_groups[group].append(xref_ext)

    # Elide empty groups
    jbig2_groups = {
@@ -256,55 +280,59 @@ def extract_images_jbig2(pike, root, log, options):
    return jbig2_groups


-def _produce_jbig2_images(jbig2_groups, root, log, options):
+def _produce_jbig2_images(
+    jbig2_groups: Dict[int, List[XrefExt]], root: Path, options
+) -> None:
    """Produce JBIG2 images from their groups"""

-    def jbig2_group_futures(executor, root, groups):
+    def jbig2_group_args(root: Path, groups: Dict[int, List[XrefExt]]):
        for group, xref_exts in groups.items():
            prefix = f'group{group:08d}'
-            future = executor.submit(
-                jbig2enc.convert_group,
+            yield dict(
                cwd=fspath(root),
                infiles=(img_name(root, xref, ext) for xref, ext in xref_exts),
                out_prefix=prefix,
            )
-            yield future

-    def jbig2_single_futures(executor, root, groups):
+    def jbig2_single_args(root, groups: Dict[int, List[XrefExt]]):
        for group, xref_exts in groups.items():
            prefix = f'group{group:08d}'
            # Second loop is to ensure multiple images per page are unpacked
            for n, xref_ext in enumerate(xref_exts):
                xref, ext = xref_ext
-                future = executor.submit(
-                    jbig2enc.convert_single,
+                yield dict(
                    cwd=fspath(root),
                    infile=img_name(root, xref, ext),
                    outfile=root / f'{prefix}.{n:04d}',
                )
-                yield future
+
+    def convert_generic(fn, kwargs_dict):
+        return fn(**kwargs_dict)

    if options.jbig2_page_group_size > 1:
-        jbig2_futures = jbig2_group_futures
+        jbig2_args = jbig2_group_args
+        jbig2_convert = partial(convert_generic, jbig2enc.convert_group)
    else:
-        jbig2_futures = jbig2_single_futures
+        jbig2_args = jbig2_single_args
+        jbig2_convert = partial(convert_generic, jbig2enc.convert_single)

-    with concurrent.futures.ThreadPoolExecutor(max_workers=options.jobs) as executor:
-        futures = jbig2_futures(executor, root, jbig2_groups)
-        with tqdm(
+    exec_progress_pool(
+        use_threads=True,
+        max_workers=options.jobs,
+        tqdm_kwargs=dict(
            total=len(jbig2_groups),
            desc="JBIG2",
            unit='item',
            disable=not options.progress_bar,
-        ) as pbar:
-            for future in concurrent.futures.as_completed(futures):
-                proc = future.result()
-                if proc.stderr:
-                    log.debug(proc.stderr.decode())
-                pbar.update()
+        ),
+        task=jbig2_convert,
+        task_arguments=jbig2_args(root, jbig2_groups),
+    )


-def convert_to_jbig2(pike, jbig2_groups, root, log, options):
+def convert_to_jbig2(
+    pike: Pdf, jbig2_groups: Dict[int, List[XrefExt]], root: Path, options
+) -> None:
    """Convert images to JBIG2 and insert into PDF.

    When the JBIG2 page group size is > 1 we do several JBIG2 images at once
@@ -318,7 +346,7 @@ def convert_to_jbig2(pike, jbig2_groups, root, log, options):
    and needs no dictionary. Currently this must be lossless JBIG2.
    """

-    _produce_jbig2_images(jbig2_groups, root, log, options)
+    _produce_jbig2_images(jbig2_groups, root, options)

    for group, xref_exts in jbig2_groups.items():
        prefix = f'group{group:08d}'
@@ -342,19 +370,19 @@ def convert_to_jbig2(pike, jbig2_groups, root, log, options):
            )


-def transcode_jpegs(pike, jpegs, root, log, options):
+def transcode_jpegs(pike: Pdf, jpegs: Sequence[Xref], root: Path, options) -> None:
    for xref in tqdm(
        jpegs, desc="JPEGs", unit='image', disable=not options.progress_bar
    ):
-        in_jpg = Path(jpg_name(root, xref))
+        in_jpg = jpg_name(root, xref)
        opt_jpg = in_jpg.with_suffix('.opt.jpg')

        # This produces a debug warning from PIL
        # DEBUG:PIL.Image:Error closing: 'NoneType' object has no attribute
        # 'close'.  Seems to be mostly harmless
        # https://github.com/python-pillow/Pillow/issues/1144
-        with Image.open(fspath(in_jpg)) as im:
-            im.save(fspath(opt_jpg), optimize=True, quality=options.jpeg_quality)
+        with Image.open(in_jpg) as im:
+            im.save(opt_jpg, optimize=True, quality=options.jpeg_quality)

        if opt_jpg.stat().st_size > in_jpg.stat().st_size:
            log.debug("xref %s, jpeg, made larger - skip", xref)
@@ -365,37 +393,46 @@ def transcode_jpegs(pike, jpegs, root, log, options):
        im_obj.write(compdata.read(), filter=Name.DCTDecode)


-def transcode_pngs(pike, images, image_name_fn, root, log, options):
-    modified = set()
+def transcode_pngs(
+    pike: Pdf,
+    images: Sequence[Xref],
+    image_name_fn: Callable[[Path, Xref], Path],
+    root: Path,
+    options,
+) -> None:
+    modified: MutableSet[Xref] = set()
    if options.optimize >= 2:
        png_quality = (
            max(10, options.png_quality - 10),
            min(100, options.png_quality + 10),
        )
-        with concurrent.futures.ThreadPoolExecutor(
-            max_workers=options.jobs
-        ) as executor:
-            futures = []
+
+        def pngquant_args():
            for xref in images:
                log.debug(image_name_fn(root, xref))
-                futures.append(
-                    executor.submit(
-                        pngquant.quantize,
-                        image_name_fn(root, xref),
-                        png_name(root, xref),
-                        png_quality[0],
-                        png_quality[1],
-                    )
+                yield (
+                    image_name_fn(root, xref),
+                    png_name(root, xref),
+                    png_quality[0],
+                    png_quality[1],
                )
                modified.add(xref)
-            with tqdm(
+
+        def pngquant_fn(args):
+            pngquant.quantize(*args)
+
+        exec_progress_pool(
+            use_threads=True,
+            max_workers=options.jobs,
+            tqdm_kwargs=dict(
                desc="PNGs",
-                total=len(futures),
+                total=len(images),
                unit='image',
                disable=not options.progress_bar,
-            ) as pbar:
-                for _future in concurrent.futures.as_completed(futures):
-                    pbar.update()
+            ),
+            task=pngquant_fn,
+            task_arguments=pngquant_args(),
+        )

    for xref in modified:
        im_obj = pike.get_object(xref, 0)
@@ -421,12 +458,12 @@ def transcode_pngs(pike, images, image_name_fn, root, log, options):
            )
            continue
        if compdata.type == leptonica.lept.L_FLATE_ENCODE:
-            return rewrite_png(pike, im_obj, compdata, log)
+            rewrite_png(pike, im_obj, compdata)
        elif compdata.type == leptonica.lept.L_G4_ENCODE:
-            return rewrite_png_as_g4(pike, im_obj, compdata, log)
+            rewrite_png_as_g4(pike, im_obj, compdata)


-def rewrite_png_as_g4(pike, im_obj, compdata, log):
+def rewrite_png_as_g4(pike: Pdf, im_obj: Object, compdata) -> None:
    im_obj.BitsPerComponent = 1
    im_obj.Width = compdata.w
    im_obj.Height = compdata.h
@@ -446,7 +483,7 @@ def rewrite_png_as_g4(pike, im_obj, compdata, log):
    return


-def rewrite_png(pike, im_obj, compdata, log):
+def rewrite_png(pike: Pdf, im_obj: Object, compdata) -> None:
    # When a PNG is inserted into a PDF, we more or less copy the IDAT section from
    # the PDF and transfer the rest of the PNG headers to PDF image metadata.
    # One thing we have to do is tell the PDF reader whether a predictor was used
@@ -499,8 +536,7 @@ def rewrite_png(pike, im_obj, compdata, log):
    im_obj.write(compdata.read(), filter=Name.FlateDecode, decode_parms=dparms)


-def optimize(input_file, output_file, context, save_settings):
-    log = context.log
+def optimize(input_file: Path, output_file: Path, context, save_settings) -> None:
    options = context.options
    if options.optimize == 0:
        safe_symlink(input_file, output_file)
@@ -514,25 +550,25 @@ def optimize(input_file, output_file, context, save_settings):
        options.jbig2_page_group_size = 10 if options.jbig2_lossy else 1

    with pikepdf.Pdf.open(input_file) as pike:
-        root = Path(output_file).parent / 'images'
+        root = output_file.parent / 'images'
        root.mkdir(exist_ok=True)

-        jpegs, pngs = extract_images_generic(pike, root, log, options)
-        transcode_jpegs(pike, jpegs, root, log, options)
+        jpegs, pngs = extract_images_generic(pike, root, options)
+        transcode_jpegs(pike, jpegs, root, options)
        # if options.optimize >= 2:
        # Try pngifying the jpegs
-        #    transcode_pngs(pike, jpegs, jpg_name, root, log, options)
-        transcode_pngs(pike, pngs, png_name, root, log, options)
+        #    transcode_pngs(pike, jpegs, jpg_name, root, options)
+        transcode_pngs(pike, pngs, png_name, root, options)

-        jbig2_groups = extract_images_jbig2(pike, root, log, options)
-        convert_to_jbig2(pike, jbig2_groups, root, log, options)
+        jbig2_groups = extract_images_jbig2(pike, root, options)
+        convert_to_jbig2(pike, jbig2_groups, root, options)

-        target_file = Path(output_file).with_suffix('.opt.pdf')
+        target_file = output_file.with_suffix('.opt.pdf')
        pike.remove_unreferenced_resources()
        pike.save(target_file, **save_settings)

-    input_size = Path(input_file).stat().st_size
-    output_size = Path(target_file).stat().st_size
+    input_size = input_file.stat().st_size
+    output_size = target_file.stat().st_size
    if output_size == 0:
        raise OutputFileAccessError(
            f"Output file not created after optimizing. We probably ran "
@@ -553,8 +589,8 @@ def optimize(input_file, output_file, context, save_settings):


 def main(infile, outfile, level, jobs=1):
-    from tempfile import TemporaryDirectory
-    from shutil import copy
+    from shutil import copy  # pylint: disable=import-outside-toplevel
+    from tempfile import TemporaryDirectory  # pylint: disable=import-outside-toplevel

    class OptimizeOptions:
        """Emulate ocrmypdf's options"""
@@ -572,6 +608,7 @@ def main(infile, outfile, level, jobs=1):
            self.quiet = True
            self.progress_bar = False

+    infile = Path(infile)
    options = OptimizeOptions(
        input_file=infile,
        jobs=jobs,
@@ -582,7 +619,7 @@ def main(infile, outfile, level, jobs=1):
    )

    with TemporaryDirectory() as td:
-        context = PDFContext(options, td, infile, None)
+        context = PdfContext(options, td, infile, None, None)
        tmpout = Path(td) / 'out.pdf'
        optimize(
            infile,
@@ -1,39 +1,17 @@
-# © 2015 James R. Barlow: github.com/jbarlow83
+# © 2020 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """
-Generate a PDFMARK file for Ghostscript >= 9.14, for PDF/A conversion
-
-pdfmark is an extension to the Postscript language that describes some PDF
-features like bookmarks and annotations. It was originally specified Adobe
-Distiller, for Postscript to PDF conversion:
-https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/pdfmark_reference.pdf
-
-Ghostscript uses pdfmark for PDF to PDF/A conversion as well. To use Ghostscript
-to create a PDF/A, we need to create a pdfmark file with the necessary metadata.
-
-This takes care of the many version-specific bugs and pecularities in
-Ghostscript's handling of pdfmark.
-
+Utilities for PDF/A production and confirmation with Ghostspcript.
 """

 import base64
 from pathlib import Path
-from string import Template
+from typing import Dict, Iterator, Union

 import pikepdf
 import pkg_resources
@@ -43,58 +21,88 @@ ICC_PROFILE_RELPATH = 'data/sRGB.icc'
 SRGB_ICC_PROFILE = pkg_resources.resource_filename('ocrmypdf', ICC_PROFILE_RELPATH)


-# This is a template written in PostScript which is needed to create PDF/A
-# files, from the Ghostscript documentation. Lines beginning with % are
-# comments. Python substitution variables have a '$' prefix.
-pdfa_def_template = u"""%!
-% Define an ICC profile :
-/ICCProfile $icc_profile
-def
+def _postscript_objdef(
+    alias: str,
+    dictionary: Dict[str, str],
+    *,
+    stream_name: str = None,
+    stream_data: bytes = None,
+) -> Iterator[str]:
+    assert (stream_name is None) == (stream_data is None)

-[/_objdef {icc_PDFA} /type /stream /OBJ pdfmark
-[{icc_PDFA} << /N 3 >> /PUT pdfmark
-[{icc_PDFA} ICCProfile /PUT pdfmark
+    objtype = '/stream' if stream_name else '/dict'

-% Define the output intent dictionary :
+    if stream_name:
+        a85_data = base64.a85encode(stream_data, adobe=True).decode('ascii')
+        yield f'{stream_name} ' + a85_data
+        yield 'def'

-[/_objdef {OutputIntent_PDFA} /type /dict /OBJ pdfmark
-[{OutputIntent_PDFA} <<
-  /Type /OutputIntent             % Must be so (the standard requires).
-  /S /GTS_PDFA1                   % Must be so (the standard requires).
-  /DestOutputProfile {icc_PDFA}            % Must be so (see above).
-  /OutputConditionIdentifier ($icc_identifier)
->> /PUT pdfmark
-[{Catalog} <</OutputIntents [ {OutputIntent_PDFA} ]>> /PUT pdfmark
-"""
+    if alias != '{Catalog}':  # Catalog needs no definition
+        yield f'[/_objdef {alias} /type {objtype} /OBJ pdfmark'
+
+    yield f'[{alias} <<'
+    for key, val in dictionary.items():
+        yield f'  {key} {val}'
+    yield '>> /PUT pdfmark'
+
+    if stream_name:
+        yield f'[{alias} {stream_name[1:]} /PUT pdfmark'


-def generate_pdfa_ps(target_filename, icc='sRGB'):
-    """Create a Postscript pdfmark file for Ghostscript PDF/A conversion
+def _make_postscript(icc_name: str, icc_data: bytes, colors: int) -> Iterator[str]:
+    yield '%!'
+    yield from _postscript_objdef(
+        '{icc_PDFA}',  # Not an f-string
+        {'/N': str(colors)},
+        stream_name='/ICCProfile',
+        stream_data=icc_data,
+    )
+    yield ''
+    yield from _postscript_objdef(
+        '{OutputIntent_PDFA}',
+        {
+            '/Type': '/OutputIntent',
+            '/S': '/GTS_PDFA1',
+            '/DestOutputProfile': '{icc_PDFA}',
+            '/OutputConditionIdentifier': f'({icc_name})',  # Only f-string
+        },
+    )
+    yield ''
+    yield from _postscript_objdef(
+        '{Catalog}', {'/OutputIntents': '[ {OutputIntent_PDFA} ]'}
+    )

-    A pdfmark file is a small Postscript program that provides some information
-    Ghostscript needs to perform PDF/A conversion. The only information we put
-    in specifies that we want the file to be a PDF/A, and we want to Ghostscript
-    to convert objects to the sRGB colorspace if it runs into any object that
-    it decides must be converted.

-    See the Adobe pdfmark Reference for details:
-    https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/pdfmark_reference.pdf
+def generate_pdfa_ps(target_filename: Path, icc: str = 'sRGB'):
+    """Create a Postscript PDFMARK file for Ghostscript PDF/A conversion

-    :param target_filename: filename to save
-    :param icc: ICC identifier such as 'sRGB'
+    pdfmark is an extension to the Postscript language that describes some PDF
+    features like bookmarks and annotations. It was originally specified Adobe
+    Distiller, for Postscript to PDF conversion.
+
+    Ghostscript uses pdfmark for PDF to PDF/A conversion as well. To use Ghostscript
+    to create a PDF/A, we need to create a pdfmark file with the necessary metadata.
+
+    This function takes care of the many version-specific bugs and pecularities in
+    Ghostscript's handling of pdfmark.
+
+    The only information we put in specifies that we want the file to be a
+    PDF/A, and we want to Ghostscript to convert objects to the sRGB colorspace
+    if it runs into any object that it decides must be converted.
+
+    Arguments:
+        target_filename: filename to save
+        icc: ICC identifier such as 'sRGB'
+    References:
+        Adobe PDFMARK Reference: https://www.adobe.com/content/dam/acom/en/devnet/acrobat/pdfs/pdfmark_reference.pdf
    """
    if icc == 'sRGB':
        icc_profile = SRGB_ICC_PROFILE
    else:
        raise NotImplementedError("Only supporting sRGB")

-    # Read the ICC profile, encode as ASCII85 and convert to a string which we
-    # will insert in the .ps file
    bytes_icc_profile = Path(icc_profile).read_bytes()
-    icc_profile = base64.a85encode(bytes_icc_profile, adobe=True).decode('ascii')
-
-    t = Template(pdfa_def_template)
-    ps = t.substitute(icc_profile=icc_profile, icc_identifier=icc)
+    ps = '\n'.join(_make_postscript(icc, bytes_icc_profile, 3))

    # We should have encoded everything to pure ASCII by this point, and
    # to be safe, only allow ASCII in PostScript
@@ -102,7 +110,7 @@ def generate_pdfa_ps(target_filename, icc='sRGB'):
    return target_filename


-def file_claims_pdfa(filename):
+def file_claims_pdfa(filename: Path):
    """Determines if the file claims to be PDF/A compliant

    This only checks if the XMP metadata contains a PDF/A marker. It does not
@@ -119,7 +127,7 @@ def file_claims_pdfa(filename):
            }
        valid_part_conforms = {'1A', '1B', '2A', '2B', '2U', '3A', '3B', '3U'}
        conformance = f'PDF/A-{pdfmeta.pdfa_status}'
-        pdfa_dict = {}
+        pdfa_dict: Dict[str, Union[str, bool]] = {}
        if pdfmeta.pdfa_status in valid_part_conforms:
            pdfa_dict['pass'] = True
            pdfa_dict['output'] = 'pdfa'
@@ -1,19 +1,9 @@
 #!/usr/bin/env python3
 # © 2015 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.

-from .info import Colorspace, Encoding, PdfInfo
+
+from ocrmypdf.pdfinfo.info import Colorspace, Encoding, PdfInfo
@@ -1,102 +0,0 @@
-# © 2018 James R. Barlow: github.com/jbarlow83
-#
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
-
-import logging
-import re
-import xml.etree.ElementTree as ET
-
-from ..exec import ghostscript
-
-gslog = logging.getLogger()
-
-# Forgive me for I have sinned
-# I am using regular expressions to parse XML. However the XML in this case,
-# generated by Ghostscript, is self-consistent enough to be parseable.
-regex_remove_char_tags = re.compile(
-    br"""
-    <char\b
-    (?:   [^>]   # anything single character but >
-        | \">\"  # special case: trap ">"
-    )*
-    />           # terminate with '/>'
-""",
-    re.VERBOSE,
-)
-
-
-def page_get_textblocks(infile, pageno, xmltext, height):
-    """Get text boxes out of Ghostscript txtwrite xml"""
-
-    root = xmltext
-    if not hasattr(xmltext, 'findall'):
-        return []
-
-    def blocks():
-        for span in root.findall('.//span'):
-            bbox_str = span.attrib['bbox']
-            font_size = span.attrib['size']
-            pts = [int(pt) for pt in bbox_str.split()]
-            pts[1] = pts[1] - int(float(font_size) + 0.5)
-            bbox_topdown = tuple(pts)
-            bb = bbox_topdown
-            bbox_bottomup = (bb[0], height - bb[3], bb[2], height - bb[1])
-            yield bbox_bottomup
-
-    def joined_blocks():
-        prev = None
-        for bbox in blocks():
-            if prev is None:
-                prev = bbox
-            if bbox[1] == prev[1] and bbox[3] == prev[3]:
-                gap = prev[2] - bbox[0]
-                height = abs(bbox[3] - bbox[1])
-                if gap < height:
-                    # Join boxes
-                    prev = (prev[0], prev[1], bbox[2], bbox[3])
-                    continue
-            # yield previously joined bboxes and start anew
-            yield prev
-            prev = bbox
-        if prev is not None:
-            yield prev
-
-    return [block for block in joined_blocks()]
-
-
-def extract_text_xml(infile, pdf, pageno=None, log=gslog):
-    existing_text = ghostscript.extract_text(infile, pageno=None)
-    existing_text = regex_remove_char_tags.sub(b' ', existing_text)
-
-    try:
-        root = ET.fromstringlist([b'<document>\n', existing_text, b'</document>\n'])
-        page_xml = root.findall('page')
-    except ET.ParseError as e:
-        log.error(
-            "An error occurred while attempting to retrieve existing text in "
-            "the input file. Will attempt to continue assuming that there is "
-            "no existing text in the file. The error was:"
-        )
-        log.error(e)
-        page_xml = [None] * len(pdf.pages)
-
-    page_count_difference = len(pdf.pages) - len(page_xml)
-    if page_count_difference != 0:
-        log.error("The number of pages in the input file is inconsistent.")
-        log.error(f"Expected {len(pdf.pages)}, txtwrite says {len(page_xml)}")
-        if page_count_difference > 0:
-            page_xml.extend([None] * page_count_difference)
-    return page_xml
@@ -1,38 +1,29 @@
 #!/usr/bin/env python3
 # © 2015 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import logging
 import re
 from collections import defaultdict, namedtuple
 from decimal import Decimal
 from enum import Enum
+from functools import partial
 from math import hypot, isclose
-from os import fspath
+from os import PathLike
 from pathlib import Path
+from typing import Any, Dict, List, Optional, Union
 from warnings import warn

 import pikepdf
 from pikepdf import PdfMatrix
-from tqdm import tqdm

+from ocrmypdf._concurrent import exec_progress_pool
 from ocrmypdf.exceptions import EncryptedPdfError
-from ocrmypdf.exec import ghostscript
-from ocrmypdf.pdfinfo import ghosttext
+from ocrmypdf.helpers import Resolution, available_cpu_count, pikepdf_enable_mmap
 from ocrmypdf.pdfinfo.layout import get_page_analysis, get_text_boxes

 logger = logging.getLogger()
@@ -40,7 +31,7 @@ logger = logging.getLogger()
 Colorspace = Enum('Colorspace', 'gray rgb cmyk lab icc index sep devn pattern jpeg2000')

 Encoding = Enum(
-    'Encoding', 'ccitt jpeg jpeg2000 jbig2 asciihex ascii85 lzw flate ' + 'runlength'
+    'Encoding', 'ccitt jpeg jpeg2000 jbig2 asciihex ascii85 lzw flate runlength'
 )

 FRIENDLY_COLORSPACE = {
@@ -90,7 +81,7 @@ UNIT_SQUARE = (1.0, 0.0, 0.0, 1.0, 0.0, 0.0)
 def _is_unit_square(shorthand):
    values = map(float, shorthand)
    pairwise = zip(values, UNIT_SQUARE)
-    return all([isclose(a, b, rel_tol=1e-3) for a, b in pairwise])
+    return all(isclose(a, b, rel_tol=1e-3) for a, b in pairwise)


 XobjectSettings = namedtuple('XobjectSettings', ['name', 'shorthand', 'stack_depth'])
@@ -98,15 +89,19 @@ XobjectSettings = namedtuple('XobjectSettings', ['name', 'shorthand', 'stack_dep
 InlineSettings = namedtuple('InlineSettings', ['iimage', 'shorthand', 'stack_depth'])

 ContentsInfo = namedtuple(
-    'ContentsInfo', ['xobject_settings', 'inline_images', 'found_vector', 'name_index']
+    'ContentsInfo',
+    ['xobject_settings', 'inline_images', 'found_vector', 'found_text', 'name_index'],
 )

 TextboxInfo = namedtuple('TextboxInfo', ['bbox', 'is_visible', 'is_corrupt'])


-class VectorInfo:
-    def __init__(self):
-        pass
+class VectorMarker:
+    pass
+
+
+class TextMarker:
+    pass


 def _normalize_stack(graphobjs):
@@ -153,9 +148,11 @@ def _interpret_contents(contentstream, initial_shorthand=UNIT_SQUARE):
    inline_images = []
    name_index = defaultdict(lambda: [])
    found_vector = False
+    found_text = False
    vector_ops = set('S s f F f* B B* b b*'.split())
+    text_showing_ops = set("""TJ Tj " '""".split())
    image_ops = set('BI ID EI q Q Do cm'.split())
-    operator_whitelist = ' '.join(vector_ops | image_ops)
+    operator_whitelist = ' '.join(vector_ops | text_showing_ops | image_ops)

    for n, graphobj in enumerate(
        _normalize_stack(
@@ -195,11 +192,14 @@ def _interpret_contents(contentstream, initial_shorthand=UNIT_SQUARE):
            inline_images.append(inline)
        elif operator in vector_ops:
            found_vector = True
+        elif operator in text_showing_ops:
+            found_text = True

    return ContentsInfo(
        xobject_settings=xobject_settings,
        inline_images=inline_images,
        found_vector=found_vector,
+        found_text=found_text,
        name_index=name_index,
    )

@@ -227,7 +227,7 @@ def _get_dpi(ctm_shorthand, image_size):
    width-axis vector v0 (1, 0), height-axis vector vh (0, 1) with the matrix,
    which gives the dimensions of the image in PDF units. From there we can
    compare to actual image dimensions. PDF uses
-    row vector * matrix_tranposed unlike the traditional
+    row vector * matrix_transposed unlike the traditional
    matrix * column vector.

    The offset, width and height vectors can be combined in a matrix and
@@ -265,7 +265,7 @@ def _get_dpi(ctm_shorthand, image_size):
    dpi_w = scale_w * 72.0
    dpi_h = scale_h * 72.0

-    return dpi_w, dpi_h
+    return Resolution(dpi_w, dpi_h)


 class ImageInfo:
@@ -356,12 +356,8 @@ class ImageInfo:
        return self._enc

    @property
-    def xres(self):
-        return _get_dpi(self._shorthand, (self._width, self._height))[0]
-
-    @property
-    def yres(self):
-        return _get_dpi(self._shorthand, (self._width, self._height))[1]
+    def dpi(self):
+        return _get_dpi(self._shorthand, (self._width, self._height))

    def __repr__(self):
        class_locals = {
@@ -371,7 +367,7 @@ class ImageInfo:
        }
        return (
            "<ImageInfo '{name}' {type_} {width}x{height} {color} "
-            "{comp} {bpc} {enc} {xres}x{yres}>"
+            "{comp} {bpc} {enc} {dpi}>"
        ).format(**class_locals)


@@ -509,13 +505,15 @@ def _process_content_streams(*, pdf, container, shorthand=None):
    contentsinfo = _interpret_contents(container, initial_shorthand)

    if contentsinfo.found_vector:
-        yield VectorInfo()
+        yield VectorMarker()
+    if contentsinfo.found_text:
+        yield TextMarker()
    yield from _find_inline_images(contentsinfo)
    yield from _find_regular_images(container, contentsinfo)
    yield from _find_form_xobject_images(pdf, container, contentsinfo)


-def _page_has_text(text_blocks, page_width, page_height):
+def _page_has_text(text_blocks, page_width, page_height) -> bool:
    """Smarter text detection that ignores text in margins"""

    pw, ph = float(page_width), float(page_height)
@@ -558,8 +556,10 @@ def simplify_textboxes(miner, textbox_getter):
        yield TextboxInfo(box.bbox, visible, corrupt)


-def _pdf_get_pageinfo(pdf, pageno: int, infile, xmltext):
-    pageinfo = {}
+def _pdf_get_pageinfo(
+    pdf, pageno: int, infile: PathLike, check_pages, detailed_analysis: bool
+):
+    pageinfo: Dict[str, Any] = {}
    pageinfo['pageno'] = pageno
    pageinfo['images'] = []

@@ -568,18 +568,18 @@ def _pdf_get_pageinfo(pdf, pageno: int, infile, xmltext):
    width_pt = mediabox[2] - mediabox[0]
    height_pt = mediabox[3] - mediabox[1]

-    if xmltext is not None:
-        bboxes = ghosttext.page_get_textblocks(
-            fspath(infile), pageno, xmltext=xmltext, height=height_pt
-        )
-        pageinfo['bboxes'] = bboxes
-    else:
+    check_this_page = pageno in check_pages
+
+    if check_this_page and detailed_analysis:
        pscript5_mode = str(pdf.docinfo.get('/Creator')).startswith('PScript5')
        miner = get_page_analysis(infile, pageno, pscript5_mode)
        pageinfo['textboxes'] = list(simplify_textboxes(miner, get_text_boxes))
        bboxes = (box.bbox for box in pageinfo['textboxes'])

-    pageinfo['has_text'] = _page_has_text(bboxes, width_pt, height_pt)
+        pageinfo['has_text'] = _page_has_text(bboxes, width_pt, height_pt)
+    else:
+        pageinfo['textboxes'] = []
+        pageinfo['has_text'] = None  # i.e. "no information"

    userunit = page.get('/UserUnit', Decimal(1.0))
    if not isinstance(userunit, Decimal):
@@ -594,99 +594,134 @@ def _pdf_get_pageinfo(pdf, pageno: int, infile, xmltext):
        pageinfo['rotate'] = 0

    userunit_shorthand = (userunit, 0, 0, userunit, 0, 0)
-    contentsinfo = [
-        ci
+
+    if check_this_page:
+        pageinfo['has_vector'] = False
+        pageinfo['has_text'] = False
+        pageinfo['images'] = []
        for ci in _process_content_streams(
            pdf=pdf, container=page, shorthand=userunit_shorthand
-        )
-    ]
+        ):
+            if isinstance(ci, VectorMarker):
+                pageinfo['has_vector'] = True
+            elif isinstance(ci, TextMarker):
+                pageinfo['has_text'] = True
+            elif isinstance(ci, ImageInfo):
+                pageinfo['images'].append(ci)
+            else:
+                raise NotImplementedError()
+    else:
+        pageinfo['has_vector'] = None  # i.e. "no information"
+        pageinfo['has_text'] = None
+        pageinfo['images'] = None

-    pageinfo['has_vector'] = False
-    if any(isinstance(ci, VectorInfo) for ci in contentsinfo):
-        pageinfo['has_vector'] = True
-
-    pageinfo['images'] = [im for im in contentsinfo if isinstance(im, ImageInfo)]
    if pageinfo['images']:
-        xres = Decimal(max(image.xres for image in pageinfo['images']))
-        yres = Decimal(max(image.yres for image in pageinfo['images']))
-        pageinfo['xres'], pageinfo['yres'] = xres, yres
-        pageinfo['width_pixels'] = int(round(xres * pageinfo['width_inches']))
-        pageinfo['height_pixels'] = int(round(yres * pageinfo['height_inches']))
+        dpi = Resolution(0.0, 0.0).take_max(image.dpi for image in pageinfo['images'])
+        pageinfo['dpi'] = dpi
+        pageinfo['width_pixels'] = int(round(dpi.x * float(pageinfo['width_inches'])))
+        pageinfo['height_pixels'] = int(round(dpi.y * float(pageinfo['height_inches'])))

    return pageinfo


-def _pdf_get_all_pageinfo(infile, detailed_analysis=False, log=None, progbar=False):
-    pdf = pikepdf.open(infile)  # Do not close in this function
-    try:
-        if pdf.is_encrypted:
-            raise EncryptedPdfError()  # Triggered by encryption with empty passwd
-        if detailed_analysis:
-            pages_xml = None
-        else:
-            pages_xml = ghosttext.extract_text_xml(infile, pdf, pageno=None, log=log)
+worker_pdf = None

-        pages = []
-        for n, _ in tqdm(
-            enumerate(pdf.pages),
-            total=len(pdf.pages),
-            desc="Scan",
-            unit='page',
-            disable=not progbar,
-        ):
-            page_xml = pages_xml[n] if pages_xml else None
-            page = PageInfo(pdf, n, infile, page_xml, detailed_analysis)
-            pages.append(page)
-    except Exception:
-        pdf.close()
-        raise

-    return pages, pdf
+def _pdf_pageinfo_sync_init(infile):
+    global worker_pdf  # pylint: disable=global-statement
+    pikepdf_enable_mmap()
+    worker_pdf = pikepdf.open(infile)
+
+
+def _pdf_pageinfo_sync(args):
+    global worker_pdf  # pylint: disable=global-statement
+    pageno, infile, check_pages, detailed_analysis = args
+    page = PageInfo(worker_pdf, pageno, infile, check_pages, detailed_analysis)
+    return page
+
+
+def _pdf_pageinfo_concurrent(
+    pdf, infile, progbar, max_workers, check_pages, detailed_analysis=False
+):
+    pages = [None] * len(pdf.pages)
+
+    def update_pageinfo(result, pbar):
+        page = result
+        pages[page.pageno] = page
+        pbar.update()
+
+    if max_workers is None:
+        max_workers = available_cpu_count()
+
+    total = len(pdf.pages)
+    contexts = ((n, infile, check_pages, detailed_analysis) for n in range(total))
+
+    use_threads = False  # No performance gain if threaded due to GIL
+    n_workers = min(1 + len(pages) // 4, max_workers)
+    if n_workers == 1:
+        # But if we decided on only one worker, there is no point in using
+        # a separate process.
+        use_threads = True
+
+    exec_progress_pool(
+        use_threads=use_threads,
+        max_workers=n_workers,
+        tqdm_kwargs=dict(
+            total=total, desc="Scanning contents", unit='page', disable=not progbar
+        ),
+        task_initializer=partial(_pdf_pageinfo_sync_init, infile),
+        task=_pdf_pageinfo_sync,
+        task_arguments=contexts,
+        task_finished=update_pageinfo,
+    )
+    return pages


 class PageInfo:
-    def __init__(self, pdf, pageno, infile, xmltext, detailed_analysis=False):
+    def __init__(self, pdf, pageno, infile, check_pages, detailed_analysis=False):
        self._pageno = pageno
        self._infile = infile
-        self._pageinfo = _pdf_get_pageinfo(pdf, pageno, infile, xmltext)
        self._detailed_analysis = detailed_analysis
+        self._pageinfo = _pdf_get_pageinfo(
+            pdf, pageno, infile, check_pages, detailed_analysis
+        )

    @property
-    def pageno(self):
+    def pageno(self) -> int:
        return self._pageno

    @property
-    def has_text(self):
+    def has_text(self) -> bool:
        return self._pageinfo['has_text']

    @property
-    def has_corrupt_text(self):
+    def has_corrupt_text(self) -> bool:
        if not self._detailed_analysis:
            raise NotImplementedError('Did not do detailed analysis')
        return any(tbox.is_corrupt for tbox in self._pageinfo['textboxes'])

    @property
-    def has_vector(self):
+    def has_vector(self) -> bool:
        return self._pageinfo['has_vector']

    @property
-    def width_inches(self):
+    def width_inches(self) -> Decimal:
        return self._pageinfo['width_inches']

    @property
-    def height_inches(self):
+    def height_inches(self) -> Decimal:
        return self._pageinfo['height_inches']

    @property
-    def width_pixels(self):
-        return int(round(self.width_inches * self.xres))
+    def width_pixels(self) -> int:
+        return int(round(float(self.width_inches) * self.dpi.x))

    @property
-    def height_pixels(self):
-        return int(round(self.height_inches * self.yres))
+    def height_pixels(self) -> int:
+        return int(round(float(self.height_inches) * self.dpi.y))

    @property
-    def rotation(self):
+    def rotation(self) -> int:
        return self._pageinfo.get('rotate', None)

    @rotation.setter
@@ -700,7 +735,9 @@ class PageInfo:
    def images(self):
        return self._pageinfo['images']

-    def get_textareas(self, visible=None, corrupt=None):
+    def get_textareas(
+        self, visible: Optional[bool] = None, corrupt: Optional[bool] = None
+    ):
        def predicate(obj, want_visible, want_corrupt):
            result = True
            if want_visible is not None:
@@ -713,7 +750,7 @@ class PageInfo:

        if 'textboxes' not in self._pageinfo:
            if visible is not None and corrupt is not None:
-                raise NotImplementedError('Ghostscript textboxes cannot be classified')
+                raise NotImplementedError('Incomplete information on textboxes')
            return self._pageinfo['bboxes']

        return (
@@ -723,19 +760,15 @@ class PageInfo:
        )

    @property
-    def xres(self):
-        return self._pageinfo.get('xres', None)
+    def dpi(self) -> Resolution:
+        return self._pageinfo.get('dpi', Resolution(0.0, 0.0))

    @property
-    def yres(self):
-        return self._pageinfo.get('yres', None)
-
-    @property
-    def userunit(self):
+    def userunit(self) -> Decimal:
        return self._pageinfo.get('userunit', None)

    @property
-    def min_version(self):
+    def min_version(self) -> str:
        if self.userunit is not None:
            return '1.6'
        else:
@@ -743,65 +776,74 @@ class PageInfo:

    def __repr__(self):
        return (
-            '<PageInfo ' 'pageno={} {}"x{}" rotation={} res={}x{} has_text={}>'
-        ).format(
-            self.pageno,
-            self.width_inches,
-            self.height_inches,
-            self.rotation,
-            self.xres,
-            self.yres,
-            self.has_text,
+            f'<PageInfo '
+            f'pageno={self.pageno} {self.width_inches}"x{self.height_inches}" '
+            f'rotation={self.rotation} dpi={self.dpi} has_text={self.has_text}>'
        )


 class PdfInfo:
    """Get summary information about a PDF"""

-    def __init__(self, infile, detailed_page_analysis=False, log=logger, progbar=False):
+    def __init__(
+        self,
+        infile,
+        detailed_analysis: bool = False,
+        progbar: bool = False,
+        max_workers: int = None,
+        check_pages=None,
+    ):
        self._infile = infile
-        if ghostscript.version() in ('9.52',):
-            detailed_page_analysis = True  # txtwrite doesn't work in these versions
-        self._pages, pdf = _pdf_get_all_pageinfo(
-            infile, detailed_page_analysis, log=log, progbar=progbar
-        )
-        self._needs_rendering = pdf.root.get('/NeedsRendering', False)
-        self._has_acroform = False
-        if '/AcroForm' in pdf.root:
-            if len(pdf.root.AcroForm.get('/Fields', [])) > 0:
-                self._has_acroform = True
-            elif '/XFA' in pdf.root.AcroForm:
-                self._has_acroform = True
-        pdf.close()
+        if check_pages is None:
+            check_pages = range(0, 1_000_000_000)
+
+        with pikepdf.open(infile) as pdf:
+            if pdf.is_encrypted:
+                raise EncryptedPdfError()  # Triggered by encryption with empty passwd
+            self._pages = _pdf_pageinfo_concurrent(
+                pdf,
+                infile,
+                progbar,
+                max_workers,
+                check_pages=check_pages,
+                detailed_analysis=detailed_analysis,
+            )
+            self._needs_rendering = pdf.root.get('/NeedsRendering', False)
+            self._has_acroform = False
+            if '/AcroForm' in pdf.root:
+                if len(pdf.root.AcroForm.get('/Fields', [])) > 0:
+                    self._has_acroform = True
+                elif '/XFA' in pdf.root.AcroForm:
+                    self._has_acroform = True

    @property
    def pages(self):
        return self._pages

    @property
-    def min_version(self):
+    def min_version(self) -> str:
        # The minimum PDF is the maximum version that any particular page needs
        return max(page.min_version for page in self.pages)

    @property
-    def has_userunit(self):
+    def has_userunit(self) -> bool:
        return any(page.userunit != 1.0 for page in self.pages)

    @property
-    def has_acroform(self):
+    def has_acroform(self) -> bool:
        return self._has_acroform

    @property
-    def filename(self):
+    def filename(self) -> Union[str, Path]:
        if not isinstance(self._infile, (str, Path)):
            raise NotImplementedError("can't get filename from stream")
        return self._infile

    @property
-    def needs_rendering(self):
+    def needs_rendering(self) -> bool:
        return self._needs_rendering

-    def __getitem__(self, item):
+    def __getitem__(self, item) -> PageInfo:
        return self._pages[item]

    def __len__(self):
@@ -812,16 +854,16 @@ class PdfInfo:


 def main():
-    import argparse
+    import argparse  # pylint: disable=import-outside-toplevel
+    from pprint import pprint  # pylint: disable=import-outside-toplevel

    parser = argparse.ArgumentParser()
    parser.add_argument('infile')
    args = parser.parse_args()
-    pagesinfo, pdfinfo = _pdf_get_all_pageinfo(args.infile)
-    from pprint import pprint
+    pdfinfo = PdfInfo(args.infile)

    pprint(pdfinfo)
-    for page in pagesinfo:
+    for page in pdfinfo.pages:
        pprint(page)
        for im in page.images:
            pprint(im)
@@ -1,19 +1,9 @@
 # © 2018 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 import re
 from math import copysign
@@ -25,65 +15,16 @@ import pdfminer.encodingdb
 import pdfminer.pdfdevice
 import pdfminer.pdfinterp
 from pdfminer.converter import PDFLayoutAnalyzer
-from pdfminer.glyphlist import glyphname2unicode
 from pdfminer.layout import LAParams, LTChar, LTPage, LTTextBox
 from pdfminer.pdfdocument import PDFTextExtractionNotAllowed
-from pdfminer.pdffont import PDFFont, PDFSimpleFont, PDFUnicodeNotDefined
+from pdfminer.pdffont import PDFSimpleFont, PDFUnicodeNotDefined
 from pdfminer.pdfpage import PDFPage
 from pdfminer.utils import bbox2str, matrix2str

-from ..exceptions import EncryptedPdfError
+from ocrmypdf.exceptions import EncryptedPdfError

 STRIP_NAME = re.compile(r'[0-9]+')

-#
-#  pdfminer 20181108 patches
-#
-
-if pdfminer.__version__ == '20181108':
-
-    def name2unicode(name):
-        """Fix pdfminer's name2unicode function
-
-        Font cids that are mapped to names of the form /g123 seem to be, by convention
-        characters with no corresponding Unicode entry. These can be subsetted fonts
-        or symbolic fonts. There seems to be no way to map /g123 fonts to Unicode,
-        barring a ToUnicode data structure.
-        """
-        if name in glyphname2unicode:
-            return glyphname2unicode[name]
-        if name.startswith('g') or name.startswith('a'):
-            raise KeyError(name)
-        if name.startswith('uni'):
-            try:
-                return chr(int(name[3:], 16))
-            except ValueError:  # Not hexadecimal
-                raise KeyError(name)
-        m = STRIP_NAME.search(name)
-        if not m:
-            raise KeyError(name)
-        return chr(int(m.group(0)))
-
-    pdfminer.encodingdb.name2unicode = name2unicode
-
-    original_PDFFont_init = PDFFont.__init__
-
-    def PDFFont__init__(self, descriptor, widths, default_width=None):
-        original_PDFFont_init(self, descriptor, widths, default_width)
-        # PDF spec says descent should be negative
-        # A font with a positive descent implies it floats entirely above the
-        # baseline, i.e. it's not really a baseline anymore. I have fonts that
-        # claim a positive descent, but treating descent as positive always seems
-        # to misposition text.
-        if self.descent > 0:
-            self.descent = -self.descent
-
-    PDFFont.__init__ = PDFFont__init__
-
-#
-# end of pdfminer 20181108 patches
-#
-

 original_PDFSimpleFont_init = PDFSimpleFont.__init__

@@ -269,7 +210,17 @@ class TextPositionTracker(PDFLayoutAnalyzer):

 def get_page_analysis(infile, pageno, pscript5_mode):
    rman = pdfminer.pdfinterp.PDFResourceManager(caching=True)
-    dev = TextPositionTracker(rman, laparams=LAParams())
+    if pdfminer.__version__ < '20200402':
+        # Workaround for https://github.com/pdfminer/pdfminer.six/issues/395
+        disable_boxes_flow = 2
+    else:
+        disable_boxes_flow = None
+    dev = TextPositionTracker(
+        rman,
+        laparams=LAParams(
+            all_texts=True, detect_vertical=True, boxes_flow=disable_boxes_flow
+        ),
+    )
    interp = pdfminer.pdfinterp.PDFPageInterpreter(rman, dev)

    if pscript5_mode:
@@ -0,0 +1,293 @@
+# © 2020 James R. Barlow: github.com/jbarlow83
+#
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+from abc import ABC, abstractmethod, abstractstaticmethod
+from argparse import ArgumentParser, Namespace
+from collections import namedtuple
+from pathlib import Path
+from typing import TYPE_CHECKING, AbstractSet, List, Optional
+
+import pluggy
+
+from ocrmypdf.helpers import Resolution
+
+if TYPE_CHECKING:
+    from PIL import Image
+
+    from ocrmypdf._jobcontext import PageContext
+    from ocrmypdf.pdfinfo import PdfInfo
+
+hookspec = pluggy.HookspecMarker('ocrmypdf')
+
+# pylint: disable=unused-argument
+
+
+@hookspec
+def add_options(parser: ArgumentParser) -> None:
+    """Allows the plugin to add its own command line and API arguments.
+
+    OCRmyPDF converts command line arguments to API arguments, so adding
+    arguments here will cause new arguments to be processed for API calls
+    to ``ocrmypdf.ocr``, or when invoked on the command line.
+
+    Note:
+        This hook will be called from the main process, and may modify global state
+        before child worker processes are forked.
+    """
+
+
+@hookspec
+def check_options(options: Namespace) -> None:
+    """Called to ask the plugin to check all of the options.
+
+    The plugin may check if options that it added are valid.
+
+    Warnings or other messages may be passed to the user by creating a logger
+    object using ``log = logging.getLogger(__name__)`` and logging to this.
+
+    The plugin may also modify the *options*. All objects that are in options
+    must be picklable so they can be marshalled to child worker processes.
+
+    Raises:
+        ocrmypdf.exceptions.ExitCodeException: If options are not acceptable
+            and the application should terminate gracefully with an informative
+            message and error code.
+    Note:
+        This hook will be called from the main process, and may modify global state
+        before child worker processes are forked.
+	"""
+
+
+@hookspec
+def validate(pdfinfo: 'PdfInfo', options: Namespace) -> None:
+    """Called to give a plugin an opportunity to review *options* and *pdfinfo*.
+
+    *options* contains the "work order" to process a particular file. *pdfinfo*
+    contains information about the input file obtained after loading and
+    parsing. The plugin may modify the *options*. For example, you could decide
+    that a certain type of file should be treated with ``options.force_ocr = True``
+    based on information in its *pdfinfo*.
+
+    Raises:
+        ocrmypdf.exceptions.ExitCodeException: If options or pdfinfo are not acceptable
+            and the application should terminate gracefully with an informative
+            message and error code.
+    Note:
+        This hook will be called from the main process, and may modify global state
+        before child worker processes are forked.
+    """
+
+
+@hookspec(firstresult=True)
+def rasterize_pdf_page(
+    input_file: Path,
+    output_file: Path,
+    raster_device: str,
+    raster_dpi: Resolution,
+    pageno: int,
+    page_dpi: Optional[Resolution] = None,
+    rotation: Optional[int] = None,
+    filter_vector: bool = False,
+) -> Path:
+    """Rasterize one page of a PDF at resolution raster_dpi in canvas units.
+
+    The image is sized to match the integer pixels dimensions implied by
+    raster_dpi even if those numbers are noninteger. The image's DPI will
+    be overridden with the values in page_dpi.
+
+    Args:
+        input_file: The PDF to rasterize.
+        output_file: The desired name of the rasterized image.
+        raster_device: Type of image to produce at output_file
+        raster_dpi: Resolution at which to rasterize page
+        pageno: Page number to rasterize (beginning at page 1)
+        page_dpi: Resolution, overriding output image DPI
+        rotation: Cardinal angle, clockwise, to rotate page
+        filter_vector: If True, remove vector graphics objects
+    Returns:
+        Path: output_file if successful
+    Note:
+        This hook will be called from child processes. Modifying global state
+        will not affect the main process or other child processes.
+    Note:
+        This is a :ref:`firstresult hook<firstresult>`.
+    """
+
+
+@hookspec(firstresult=True)
+def filter_ocr_image(page: 'PageContext', image: 'Image') -> 'Image':
+    """Called to filter the image before it is sent to OCR.
+
+    This is the image that OCR sees, not what the user sees when they view the
+    PDF. If ``redo_ocr`` is enabled, portions of the image will be masked so
+    they are not shown to OCR. The main use of this hook is expected to be hiding
+    content from OCR.
+
+    The input image may be color, grayscale, or monochrome, and the
+    output image may differ. The pixel width and height of the
+    output image must be identical to the input image, or misalignment between
+    the OCR text layer and visual position of the text will occur. Likewise,
+    the output must be a faithful representation of the input, or alignment
+    errors may occurs.
+
+    Tesseract OCR only deals with monochrome images, and internally converts
+    non-monochrome images to OCR.
+
+    Note:
+        This hook will be called from child processes. Modifying global state
+        will not affect the main process or other child processes.
+    Note:
+        This is a :ref:`firstresult hook<firstresult>`.
+    """
+
+
+@hookspec(firstresult=True)
+def filter_page_image(page: 'PageContext', image_filename: Path) -> Path:
+    """Called to filter the whole page before it is inserted into the PDF.
+
+    A whole page image is only produced when preprocessing command line arguments
+    are issued or when ``--force-ocr`` is issued. If no whole page is image is
+    produced for a given page, this function will not be called. This is not
+    the image that will be shown to OCR.
+
+    ocrmypdf will create the PDF page based on the image format used. If you
+    convert the image to a JPEG, the output page will be created as a JPEG, etc.
+    Note that the ocrmypdf image optimization stage may ultimately chose a
+    different format.
+
+    Note:
+        This hook will be called from child processes. Modifying global state
+        will not affect the main process or other child processes.
+    Note:
+        This is a :ref:`firstresult hook<firstresult>`.
+    """
+
+
+OrientationConfidence = namedtuple('OrientationConfidence', ('angle', 'confidence'))
+"""Expresses an OCR engine's confidence in page rotation.
+
+Attributes:
+    angle (int): The clockwise angle (0, 90, 180, 270) that the page should be
+        rotated. 0 means no rotation.
+    confidence (float): How confident the OCR engine is that this the correct
+        rotation. 0 is not confident, 15 is very confident. Arbitrary units.
+"""
+
+
+class OcrEngine(ABC):
+    """A class representing an OCR engine with capabilities similar to Tesseract OCR.
+
+    This could be used to create a plugin for another OCR engine instead of
+    Tesseract OCR.
+    """
+
+    @abstractstaticmethod
+    def version() -> str:
+        """Returns the version of the OCR engine."""
+
+    @abstractstaticmethod
+    def creator_tag(options: Namespace) -> str:
+        """Returns the creator tag to identify this software's role in creating the PDF.
+
+        This tag will be inserted in the XMP metadata and DocumentInfo dictionary
+        as appropriate. Ideally you should include the name of the OCR engine and its
+        version. The text should not contain line breaks. This is to help developers
+        like yourself identify the software that produced this file.
+
+        OCRmyPDF will always prepend its name to this value.
+        """
+
+    @abstractmethod
+    def __str__(self):
+        """Returns name of OCR engine and version.
+
+        This is used when OCRmyPDF wants to mention the name of the OCR engine
+        to the user, usually in an error message.
+        """
+
+    @abstractstaticmethod
+    def languages(options: Namespace) -> AbstractSet[str]:
+        """Returns the set of all languages that are supported by the engine.
+
+        Languages are typically given in 3-letter ISO 3166-1 codes, but actually
+        can be any value understood by the OCR engine."""
+
+    @abstractstaticmethod
+    def get_orientation(input_file: Path, options: Namespace) -> OrientationConfidence:
+        """Returns the orientation of the image."""
+
+    @abstractstaticmethod
+    def generate_hocr(
+        input_file: Path, output_hocr: Path, output_text: Path, options: Namespace
+    ) -> None:
+        """Called to produce a hOCR file and sidecar text file."""
+
+    @abstractstaticmethod
+    def generate_pdf(
+        input_file: Path, output_pdf: Path, output_text: Path, options: Namespace
+    ) -> None:
+        """Called to produce a text only PDF.
+
+        Args:
+            input_file: A page image on which to perform OCR.
+            output_pdf: The expected name of the output PDF, which must be
+                a single page PDF with no visible content of any kind, sized
+                to the dimensions implied by the input_file's width, height
+                and DPI. The image will be grafted onto the input PDF page.
+        """
+
+
+@hookspec(firstresult=True)
+def get_ocr_engine() -> OcrEngine:
+    """Returns an OcrEngine to use for processing this file.
+
+    The OcrEngine may be instantiated multiple times, by both the main process
+    and child process. As such, it must be obtain store any state in ``options``
+    or some common location.
+
+    Note:
+        This is a :ref:`firstresult hook<firstresult>`.
+    """
+
+
+@hookspec(firstresult=True)
+def generate_pdfa(
+    pdf_pages: List[Path],
+    pdfmark: Path,
+    output_file: Path,
+    compression: str,
+    pdf_version: str,
+    pdfa_part: str,
+) -> Path:
+    """Generate a PDF/A.
+
+    This API strongly assumes a PDF/A generator with Ghostscript's semantics.
+
+    OCRmyPDF will modify the metadata and possibly linearize the PDF/A after it
+    is generated.
+
+    Arguments:
+        pdf_pages: A list of one or more filenames, will be merged into output_file.
+        pdfmark: A PostScript file intended for Ghostscript with details on
+            how to perform the PDF/A conversion.
+        output_file: The name of the desired output file.
+        compression: One of ``'jpeg'``, ``'lossless'``, ``''``. For ``'jpeg'``,
+            the PDF/A generator should convert all images to JPEG encoding where
+            possible. For lossless, all images should be converted to FlateEncode
+            (lossless PNG). If an empty string, the PDF generator should make its
+            own decisions about how to encode images.
+        pdf_version: The minimum PDF version that the output file should be.
+            At its own discretion, the PDF/A generator may raise the version,
+            but should not lower it.
+        pdfa_part: The desired PDF/A compliance level, such as ``'2B'``.
+
+    Returns:
+        Path: If successful, the hook should return ``output_file``.
+
+    Note:
+        This is a :ref:`firstresult hook<firstresult>`.
+    """
@@ -1,37 +1,27 @@
 # © 2020 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+
+"""Utilities to measure OCR quality"""
+

 import re
 from typing import Iterable

-"""Utilities to measure OCR quality"""
-

 class OcrQualityDictionary:
    """Manages a dictionary for simple OCR quality checks."""

-    def __init__(self, *, wordlist: Iterable[str] = []):
+    def __init__(self, *, wordlist: Iterable[str]):
        """Construct a dictionary from a list of words.

        Words for which capitalization is important should be capitalized in the
        dictionary. Words that contain spaces or other punctuation will never match.
        """
-        self.dictionary = set()
-        self.dictionary.update(w for w in wordlist)
+        self.dictionary = set(wordlist)

    def measure_words_matched(self, ocr_text: str) -> float:
        """Check how many unique words in the OCR text match a dictionary.
@@ -1,19 +1,9 @@
-# © 2016 James R. Barlow: github.com/jbarlow83
+# © 2020 James R. Barlow: github.com/jbarlow83
 #
-# This file is part of OCRmyPDF.
-#
-# OCRmyPDF is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-#
-# OCRmyPDF is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-#
-# You should have received a copy of the GNU General Public License
-# along with OCRmyPDF.  If not, see <http://www.gnu.org/licenses/>.
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+

 """Wrappers to manage subprocess calls"""

@@ -23,79 +13,95 @@ import re
 import shutil
 import sys
 from collections.abc import Mapping
+from contextlib import suppress
+from distutils.version import LooseVersion
 from functools import lru_cache
+from pathlib import Path
 from subprocess import PIPE, STDOUT, CalledProcessError
 from subprocess import run as subprocess_run

-from ..exceptions import ExitCode, MissingDependencyError
+from ocrmypdf.exceptions import MissingDependencyError

 log = logging.getLogger(__name__)


-def _get_program(args, env=None):
-    program = args[0]
-    test_path = env.get('_OCRMYPDF_TEST_PATH', '')
-    if test_path:
-        program = shutil.which(program, path=test_path)
-    return program
-
-
 def run(args, *, env=None, **kwargs):
-    """Wrapper around subprocess.run()
-
-    The main purpose of this wrapper is to allow us to substitute the main program
-    for a spoof in the test suite. The hidden variable _OCRMYPDF_TEST_PATH replaces
-    the main PATH as a location to check for programs to run.
-
-    Secondly we have to account for behavioral differences in Windows in particular.
-    Creating symbolic links in Windows requires administrator privileges and
-    may not work if for some reason we're using a FAT file system or the temporary
-    folder is on a different drive from the working folder. The test suite
-    works around this by creating shim Python scripts that perform the same function
-    as a symbolic link, but those shims require support on this side, to ensure
-    we call them with Python.
+    """Wrapper around :py:func:`subprocess.run`

+    The main purpose of this wrapper is to log subprocess output in an orderly
+    fashion that indentifies the responsible subprocess. An additional
+    task is that this function goes to greater lengths to find possible Windows
+    locations of our dependencies when they are not on the system PATH.
    """
    if not env:
        env = os.environ

    # Search in spoof path if necessary
-    program = _get_program(args, env)
-
-    # If we are running a .py on Windows, ensure we call it with this Python
-    # (to support test suite shims)
-    if os.name == 'nt' and program.lower().endswith('.py'):
-        args = [sys.executable, program] + args[1:]
-    else:
-        args = [program] + args[1:]
+    program = args[0]

    if os.name == 'nt':
-        paths = os.pathsep.join(os.get_exec_path(env))
-        if not shutil.which(args[0], path=paths):
-            shimmed_path = shim_paths_with_program_files(env)
-            new_args0 = shutil.which(args[0], path=shimmed_path)
-            if new_args0:
-                args[0] = new_args0
+        args = _fix_windows_args(program, args, env)

-    process_log = log.getChild(os.path.basename(program))
-    process_log.debug("Running: %s", args)
+    log.debug("Running: %s", args)
+    process_log = log.getChild('subprocess.' + os.path.basename(program))
    if sys.version_info < (3, 7) and os.name == 'nt':
        # Can't use close_fds=True on Windows with Python 3.6 or older
        # https://bugs.python.org/issue19575, etc.
        kwargs['close_fds'] = False
-    proc = subprocess_run(args, env=env, **kwargs)
-    if process_log.isEnabledFor(logging.DEBUG):
-        try:
-            stderr = proc.stderr.decode('utf-8', 'replace')
-        except AttributeError:
-            stderr = proc.stderr
-        if stderr:
+
+    stderr = None
+    try:
+        proc = subprocess_run(args, env=env, **kwargs)
+    except CalledProcessError as e:
+        stderr = getattr(e, 'stderr', None)
+        raise
+    else:
+        stderr = getattr(proc, 'stderr', None)
+    finally:
+        if process_log.isEnabledFor(logging.DEBUG) and stderr:
+            with suppress(AttributeError, UnicodeDecodeError):
+                stderr = stderr.decode('utf-8', 'replace')
            process_log.debug("stderr = %s", stderr)
    return proc


-def get_version(program, *, version_arg='--version', regex=r'(\d+(\.\d+)*)', env=None):
-    """Get the version of the specified program"""
+def _fix_windows_args(program, args, env):
+    """Adjust our desired program and command line arguments for use on Windows"""
+
+    if sys.version_info < (3, 8):
+        # bpo-33617 - Windows needs manual Path -> str conversion
+        args = [os.fspath(arg) for arg in args]
+        program = os.fspath(program)
+
+    # If we are running a .py on Windows, ensure we call it with this Python
+    # (to support test suite shims)
+    if program.lower().endswith('.py'):
+        args = [sys.executable] + args
+
+    paths = os.pathsep.join(os.get_exec_path(env))
+    if not shutil.which(args[0], path=paths):
+        # If the program we want is not on the PATH, add some interesting
+        # locations in %PROGRAMFILES% to the PATH and try again
+        shimmed_path = shim_paths_with_program_files(env)
+        new_args0 = shutil.which(args[0], path=shimmed_path)
+        if new_args0:
+            args[0] = new_args0
+    return args
+
+
+@lru_cache(maxsize=None)
+def get_version(
+    program: str, *, version_arg: str = '--version', regex=r'(\d+(\.\d+)*)', env=None
+):
+    """Get the version of the specified program
+
+    Arguments:
+        program: The program to version check.
+        version_arg: The argument needed to ask for its version, e.g. ``--version``.
+        regex: A regular expression to parse the program's output and obtain the
+            version.
+        env: Custom ``os.environ`` in which to run program.
+    """
    args_prog = [program, version_arg]
    try:
        proc = run(
@@ -137,24 +143,25 @@ def shim_paths_with_program_files(env=None):
    program_files = env.get('PROGRAMFILES', '')
    if not program_files:
        return env.get('PATH', '')
-    paths = []
-    try:
-        for dirname in os.listdir(program_files):
-            if dirname.lower() == 'tesseract-ocr':
-                paths.append(os.path.join(program_files, dirname))
-            elif dirname.lower() == 'gs':
-                try:
-                    latest_gs = max(
-                        os.listdir(os.path.join(program_files, dirname)),
-                        key=lambda d: float(d[2:]),
-                    )
-                except (FileNotFoundError, NotADirectoryError):
-                    continue
-                paths.append(os.path.join(program_files, dirname, latest_gs, 'bin'))
-    except EnvironmentError:
-        pass
-    paths.extend(path for path in os.get_exec_path(env) if path not in set(paths))
-    return os.pathsep.join(paths)
+
+    def path_walker():
+        for path in Path(program_files).iterdir():
+            if not path.is_dir():
+                continue
+            if path.name.lower() == 'tesseract-ocr':
+                yield path
+            elif path.name.lower() == 'gs':
+                yield from (p for p in path.glob('**/bin') if p.is_dir())
+
+    paths = sorted(
+        (p for p in path_walker()), key=lambda p: (p.name, p.parent.name), reverse=True
+    )
+    paths.extend(
+        Path(str_path)
+        for str_path in os.get_exec_path(env)
+        if Path(str_path) not in set(paths)
+    )
+    return os.pathsep.join(str(p) for p in paths)


 missing_program = '''
@@ -232,10 +239,10 @@ def _error_trailer(program, package, **kwargs):


 def _error_missing_program(program, package, required_for, recommended):
-    if required_for:
+    if recommended:
+        log.warning(missing_recommend_program.format(**locals()))
+    elif required_for:
        log.error(missing_optional_program.format(**locals()))
-    elif recommended:
-        log.info(missing_recommend_program.format(**locals()))
    else:
        log.error(missing_program.format(**locals()))
    _error_trailer(**locals())
@@ -257,20 +264,27 @@ def check_external_program(
    need_version,
    required_for=None,
    recommended=False,
-    **kwargs,  # To consume log parameter
 ):
-    if kwargs:
-        if not 'log' in kwargs:
-            log.warning('check_external_program(log=...) is deprecated')
    try:
-        found_version = version_checker()
+        if callable(version_checker):
+            found_version = version_checker()
+        else:
+            found_version = version_checker
    except (CalledProcessError, FileNotFoundError, MissingDependencyError):
        _error_missing_program(program, package, required_for, recommended)
        if not recommended:
            raise MissingDependencyError()
        return

-    if found_version < need_version:
+    def remove_leading_v(s):
+        if s.startswith('v'):
+            return s[1:]
+        return s
+
+    found_version = remove_leading_v(found_version)
+    need_version = remove_leading_v(need_version)
+
+    if found_version and LooseVersion(found_version) < LooseVersion(need_version):
        _error_old_version(program, package, need_version, found_version, required_for)
        if not recommended:
            raise MissingDependencyError()
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.0.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.1.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.1.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.1.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -4,12 +4,12 @@
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
 <head>
  <title></title>
-<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
-  <meta name='ocr-system' content='tesseract 4.0.0' />
+  <meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
+  <meta name='ocr-system' content='tesseract 4.1.1' />
  <meta name='ocr-capabilities' content='ocr_page ocr_carea ocr_par ocr_line ocrx_word ocrp_wconf'/>
-</head>
-<body>
-  <div class='ocr_page' id='page_1' title='image "/var/folders/2s/7t022mgj0h5cprbq0dtb1ksm0000gn/T/com.github.ocrmypdf.xam82ph5/000001_ocr.png"; bbox 0 0 1000 800; ppageno 0'>
+ </head>
+ <body>
+  <div class='ocr_page' id='page_1' title='image "/var/folders/2s/7t022mgj0h5cprbq0dtb1ksm0000gn/T/com.github.ocrmypdf.mrqsewbu/000001_ocr.png"; bbox 0 0 1000 800; ppageno 0'>
   <div class='ocr_carea' id='block_1_1' title="bbox 296 96 704 504">
    <p class='ocr_par' id='par_1_1' lang='eng' title="bbox 296 96 704 504">
     <span class='ocr_line' id='line_1_1' title="bbox 296 96 704 504; baseline 0 296; x_size 169.33333; x_descenders 42.333332; x_ascenders 42.333336">
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.0.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.0.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -4,19 +4,19 @@
 <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
 <head>
  <title></title>
-<meta http-equiv="Content-Type" content="text/html;charset=utf-8" />
-  <meta name='ocr-system' content='tesseract 4.0.0' />
+  <meta http-equiv="Content-Type" content="text/html;charset=utf-8"/>
+  <meta name='ocr-system' content='tesseract 4.1.1' />
  <meta name='ocr-capabilities' content='ocr_page ocr_carea ocr_par ocr_line ocrx_word ocrp_wconf'/>
-</head>
-<body>
-  <div class='ocr_page' id='page_1' title='image "/var/folders/2s/7t022mgj0h5cprbq0dtb1ksm0000gn/T/com.github.ocrmypdf.6a60f5yy/000001_ocr.png"; bbox 0 0 2550 3300; ppageno 0'>
+ </head>
+ <body>
+  <div class='ocr_page' id='page_1' title='image "/var/folders/2s/7t022mgj0h5cprbq0dtb1ksm0000gn/T/com.github.ocrmypdf.ces85e5u/000001_ocr.png"; bbox 0 0 2550 3300; ppageno 0'>
   <div class='ocr_carea' id='block_1_1' title="bbox 582 131 1968 303">
    <p class='ocr_par' id='par_1_1' lang='eng' title="bbox 582 131 1968 303">
-     <span class='ocr_line' id='line_1_1' title="bbox 882 131 1657 217; baseline 0.001 -17; x_size 85; x_descenders 16; x_ascenders 19">
+     <span class='ocr_header' id='line_1_1' title="bbox 882 131 1657 217; baseline 0.001 -17; x_size 85; x_descenders 16; x_ascenders 19">
      <span class='ocrx_word' id='word_1_1' title='bbox 882 132 1036 202; x_wconf 93'>The</span>
      <span class='ocrx_word' id='word_1_2' title='bbox 1061 131 1657 217; x_wconf 91'>LinnSequencer</span>
     </span>
-     <span class='ocr_line' id='line_1_2' title="bbox 582 215 1968 303; baseline 0 -17; x_size 87; x_descenders 16; x_ascenders 21">
+     <span class='ocr_header' id='line_1_2' title="bbox 582 215 1968 303; baseline 0 -17; x_size 87; x_descenders 16; x_ascenders 21">
      <span class='ocrx_word' id='word_1_3' title='bbox 582 215 674 286; x_wconf 96'>32</span>
      <span class='ocrx_word' id='word_1_4' title='bbox 697 218 923 288; x_wconf 95'>Track</span>
      <span class='ocrx_word' id='word_1_5' title='bbox 948 218 1181 287; x_wconf 96'>MIDI</span>
@@ -27,27 +27,27 @@
   </div>
   <div class='ocr_carea' id='block_1_2' title="bbox 347 380 2188 574">
    <p class='ocr_par' id='par_1_2' lang='eng' title="bbox 347 380 2188 423">
-     <span class='ocr_line' id='line_1_3' title="bbox 347 380 2188 423; baseline -0.001 -12; x_size 38; x_descenders 8; x_ascenders 10">
+     <span class='ocr_header' id='line_1_3' title="bbox 347 380 2188 423; baseline -0.001 -12; x_size 38; x_descenders 8; x_ascenders 10">
      <span class='ocrx_word' id='word_1_8' title='bbox 347 380 412 410; x_wconf 93'>The</span>
-      <span class='ocrx_word' id='word_1_9' title='bbox 424 380 661 417; x_wconf 92'>LinnSequencer</span>
-      <span class='ocrx_word' id='word_1_10' title='bbox 663 380 712 411; x_wconf 96'>is</span>
+      <span class='ocrx_word' id='word_1_9' title='bbox 424 380 676 417; x_wconf 92'>LinnSequencer</span>
+      <span class='ocrx_word' id='word_1_10' title='bbox 688 380 712 411; x_wconf 96'>is</span>
      <span class='ocrx_word' id='word_1_11' title='bbox 724 390 743 411; x_wconf 96'>a</span>
      <span class='ocrx_word' id='word_1_12' title='bbox 754 381 1005 423; x_wconf 96'>state-of-the-art</span>
      <span class='ocrx_word' id='word_1_13' title='bbox 1017 380 1226 418; x_wconf 96'>composition</span>
      <span class='ocrx_word' id='word_1_14' title='bbox 1238 381 1299 411; x_wconf 96'>and</span>
-      <span class='ocrx_word' id='word_1_15' title='bbox 1311 380 1507 418; x_wconf 96'>performance</span>
-      <span class='ocrx_word' id='word_1_16' title='bbox 1509 385 1591 411; x_wconf 96'>tool</span>
-      <span class='ocrx_word' id='word_1_17' title='bbox 1593 380 1663 411; x_wconf 97'>for</span>
+      <span class='ocrx_word' id='word_1_15' title='bbox 1311 380 1525 418; x_wconf 96'>performance</span>
+      <span class='ocrx_word' id='word_1_16' title='bbox 1536 380 1602 411; x_wconf 96'>tool</span>
+      <span class='ocrx_word' id='word_1_17' title='bbox 1615 380 1663 411; x_wconf 97'>for</span>
      <span class='ocrx_word' id='word_1_18' title='bbox 1674 381 1725 410; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_19' title='bbox 1737 380 1940 417; x_wconf 95'>professional</span>
-      <span class='ocrx_word' id='word_1_20' title='bbox 1952 380 2103 411; x_wconf 96'>musician.</span>
-      <span class='ocrx_word' id='word_1_21' title='bbox 2106 381 2152 410; x_wconf 96'>It</span>
+      <span class='ocrx_word' id='word_1_20' title='bbox 1952 380 2112 411; x_wconf 96'>musician.</span>
+      <span class='ocrx_word' id='word_1_21' title='bbox 2127 381 2152 410; x_wconf 96'>It</span>
      <span class='ocrx_word' id='word_1_22' title='bbox 2164 380 2188 410; x_wconf 96'>is</span>
     </span>
    </p>

    <p class='ocr_par' id='par_1_3' lang='eng' title="bbox 347 430 1988 468">
-     <span class='ocr_line' id='line_1_4' title="bbox 347 430 1988 468; baseline 0 -8; x_size 37; x_descenders 7; x_ascenders 9">
+     <span class='ocr_header' id='line_1_4' title="bbox 347 430 1988 468; baseline 0 -8; x_size 37; x_descenders 7; x_ascenders 9">
      <span class='ocrx_word' id='word_1_23' title='bbox 347 430 507 467; x_wconf 96'>extremely</span>
      <span class='ocrx_word' id='word_1_24' title='bbox 518 430 677 467; x_wconf 96'>powerful,</span>
      <span class='ocrx_word' id='word_1_25' title='bbox 691 435 739 467; x_wconf 96'>yet</span>
@@ -66,7 +66,7 @@
    </p>

    <p class='ocr_par' id='par_1_4' lang='eng' title="bbox 350 482 2093 574">
-     <span class='ocr_line' id='line_1_5' title="bbox 350 482 2093 527; baseline 0 -9; x_size 43; x_descenders 7; x_ascenders 11">
+     <span class='ocr_header' id='line_1_5' title="bbox 350 482 2093 527; baseline 0 -9; x_size 43; x_descenders 7; x_ascenders 11">
      <span class='ocrx_word' id='word_1_37' title='bbox 350 490 368 508; x_wconf 73'>¢</span>
      <span class='ocrx_word' id='word_1_38' title='bbox 383 482 585 526; x_wconf 95'>Operation</span>
      <span class='ocrx_word' id='word_1_39' title='bbox 598 482 627 518; x_wconf 96'>is</span>
@@ -81,18 +81,18 @@
      <span class='ocrx_word' id='word_1_48' title='bbox 1741 483 1957 525; x_wconf 96'>RECORD,</span>
      <span class='ocrx_word' id='word_1_49' title='bbox 1974 483 2093 518; x_wconf 96'>FAST</span>
     </span>
-     <span class='ocr_line' id='line_1_6' title="bbox 383 532 1345 574; baseline 0.001 -7; x_size 43; x_descenders 7; x_ascenders 11">
+     <span class='ocr_header' id='line_1_6' title="bbox 383 532 1345 574; baseline 0.001 -7; x_size 43; x_descenders 7; x_ascenders 11">
      <span class='ocrx_word' id='word_1_50' title='bbox 383 532 635 574; x_wconf 96'>FORWARD,</span>
      <span class='ocrx_word' id='word_1_51' title='bbox 652 532 865 574; x_wconf 95'>REWIND,</span>
      <span class='ocrx_word' id='word_1_52' title='bbox 882 532 956 568; x_wconf 95'>and</span>
-      <span class='ocrx_word' id='word_1_53' title='bbox 971 532 1131 568; x_wconf 95'>LOCATE</span>
-      <span class='ocrx_word' id='word_1_54' title='bbox 1132 532 1345 568; x_wconf 95'>controls.</span>
+      <span class='ocrx_word' id='word_1_53' title='bbox 971 532 1163 568; x_wconf 95'>LOCATE</span>
+      <span class='ocrx_word' id='word_1_54' title='bbox 1177 532 1345 568; x_wconf 95'>controls.</span>
     </span>
    </p>
   </div>
   <div class='ocr_carea' id='block_1_3' title="bbox 349 589 2136 685">
    <p class='ocr_par' id='par_1_5' lang='eng' title="bbox 349 589 2136 685">
-     <span class='ocr_line' id='line_1_7' title="bbox 349 589 2136 634; baseline 0.001 -9; x_size 44; x_descenders 8; x_ascenders 11">
+     <span class='ocr_header' id='line_1_7' title="bbox 349 589 2136 634; baseline 0.001 -9; x_size 44; x_descenders 8; x_ascenders 11">
      <span class='ocrx_word' id='word_1_55' title='bbox 349 597 368 615; x_wconf 59'>e</span>
      <span class='ocrx_word' id='word_1_56' title='bbox 383 590 482 625; x_wconf 96'>Each</span>
      <span class='ocrx_word' id='word_1_57' title='bbox 496 589 539 625; x_wconf 96'>of</span>
@@ -108,7 +108,7 @@
      <span class='ocrx_word' id='word_1_67' title='bbox 1934 590 2035 626; x_wconf 96'>track</span>
      <span class='ocrx_word' id='word_1_68' title='bbox 2050 600 2136 634; x_wconf 96'>may</span>
     </span>
-     <span class='ocr_line' id='line_1_8' title="bbox 383 639 2022 685; baseline 0.001 -10; x_size 44; x_descenders 8; x_ascenders 11">
+     <span class='ocr_header' id='line_1_8' title="bbox 383 639 2022 685; baseline 0.001 -10; x_size 44; x_descenders 8; x_ascenders 11">
      <span class='ocrx_word' id='word_1_69' title='bbox 383 639 428 675; x_wconf 95'>be</span>
      <span class='ocrx_word' id='word_1_70' title='bbox 442 639 607 684; x_wconf 95'>assigned</span>
      <span class='ocrx_word' id='word_1_71' title='bbox 621 645 659 676; x_wconf 96'>to</span>
@@ -135,7 +135,7 @@
   </div>
   <div class='ocr_carea' id='block_1_5' title="bbox 349 748 2117 793">
    <p class='ocr_par' id='par_1_7' lang='eng' title="bbox 349 748 2117 793">
-     <span class='ocr_line' id='line_1_10' title="bbox 349 748 2117 793; baseline 0 -9; x_size 45; x_descenders 9; x_ascenders 11">
+     <span class='ocr_header' id='line_1_10' title="bbox 349 748 2117 793; baseline 0 -9; x_size 45; x_descenders 9; x_ascenders 11">
      <span class='ocrx_word' id='word_1_84' title='bbox 349 755 367 774; x_wconf 58'>¢</span>
      <span class='ocrx_word' id='word_1_85' title='bbox 383 748 573 784; x_wconf 91'>Ultra-fast</span>
      <span class='ocrx_word' id='word_1_86' title='bbox 588 749 677 784; x_wconf 22'>3%”</span>
@@ -147,8 +147,8 @@
      <span class='ocrx_word' id='word_1_92' title='bbox 1330 748 1368 784; x_wconf 96'>in</span>
      <span class='ocrx_word' id='word_1_93' title='bbox 1382 748 1535 785; x_wconf 96'>seconds</span>
      <span class='ocrx_word' id='word_1_94' title='bbox 1550 748 1624 784; x_wconf 96'>and</span>
-      <span class='ocrx_word' id='word_1_95' title='bbox 1638 748 1728 784; x_wconf 96'>holds</span>
-      <span class='ocrx_word' id='word_1_96' title='bbox 1730 759 1844 784; x_wconf 96'>over</span>
+      <span class='ocrx_word' id='word_1_95' title='bbox 1638 748 1746 784; x_wconf 96'>holds</span>
+      <span class='ocrx_word' id='word_1_96' title='bbox 1761 759 1844 784; x_wconf 96'>over</span>
      <span class='ocrx_word' id='word_1_97' title='bbox 1859 749 2000 791; x_wconf 96'>110,000</span>
      <span class='ocrx_word' id='word_1_98' title='bbox 2013 753 2117 784; x_wconf 96'>notes</span>
     </span>
@@ -164,23 +164,23 @@
   </div>
   <div class='ocr_carea' id='block_1_7' title="bbox 349 855 2030 1016">
    <p class='ocr_par' id='par_1_9' lang='eng' title="bbox 349 855 2030 1016">
-     <span class='ocr_line' id='line_1_12' title="bbox 350 855 1638 900; baseline 0.001 -9; x_size 45; x_descenders 9; x_ascenders 11">
+     <span class='ocr_header' id='line_1_12' title="bbox 350 855 1638 900; baseline 0.001 -9; x_size 45; x_descenders 9; x_ascenders 11">
      <span class='ocrx_word' id='word_1_101' title='bbox 350 863 367 881; x_wconf 45'>¢</span>
-      <span class='ocrx_word' id='word_1_102' title='bbox 383 856 444 891; x_wconf 95'>One</span>
-      <span class='ocrx_word' id='word_1_103' title='bbox 445 866 502 891; x_wconf 96'>or</span>
-      <span class='ocrx_word' id='word_1_104' title='bbox 503 855 580 891; x_wconf 96'>all</span>
+      <span class='ocrx_word' id='word_1_102' title='bbox 383 856 464 891; x_wconf 95'>One</span>
+      <span class='ocrx_word' id='word_1_103' title='bbox 478 866 520 891; x_wconf 96'>or</span>
+      <span class='ocrx_word' id='word_1_104' title='bbox 534 855 580 891; x_wconf 96'>all</span>
      <span class='ocrx_word' id='word_1_105' title='bbox 594 856 712 892; x_wconf 95'>tracks</span>
      <span class='ocrx_word' id='word_1_106' title='bbox 726 867 811 900; x_wconf 95'>may</span>
      <span class='ocrx_word' id='word_1_107' title='bbox 823 856 869 892; x_wconf 81'>be</span>
-      <span class='ocrx_word' id='word_1_108' title='bbox 882 856 1175 892; x_wconf 96'>TRANSPOSED</span>
-      <span class='ocrx_word' id='word_1_109' title='bbox 1178 857 1264 892; x_wconf 96'>at</span>
+      <span class='ocrx_word' id='word_1_108' title='bbox 882 856 1212 892; x_wconf 96'>TRANSPOSED</span>
+      <span class='ocrx_word' id='word_1_109' title='bbox 1227 861 1264 892; x_wconf 96'>at</span>
      <span class='ocrx_word' id='word_1_110' title='bbox 1277 856 1338 892; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_111' title='bbox 1351 856 1463 892; x_wconf 96'>touch</span>
-      <span class='ocrx_word' id='word_1_112' title='bbox 1477 867 1501 892; x_wconf 96'>of</span>
-      <span class='ocrx_word' id='word_1_113' title='bbox 1502 856 1554 892; x_wconf 96'>a</span>
+      <span class='ocrx_word' id='word_1_112' title='bbox 1477 856 1520 892; x_wconf 96'>of</span>
+      <span class='ocrx_word' id='word_1_113' title='bbox 1531 867 1554 892; x_wconf 96'>a</span>
      <span class='ocrx_word' id='word_1_114' title='bbox 1568 856 1638 900; x_wconf 96'>key.</span>
     </span>
-     <span class='ocr_line' id='line_1_13' title="bbox 350 913 1535 958; baseline 0.001 -9; x_size 44; x_descenders 8; x_ascenders 11">
+     <span class='ocr_header' id='line_1_13' title="bbox 350 913 1535 958; baseline 0.001 -9; x_size 44; x_descenders 8; x_ascenders 11">
      <span class='ocrx_word' id='word_1_115' title='bbox 350 921 367 939; x_wconf 45'>e</span>
      <span class='ocrx_word' id='word_1_116' title='bbox 383 913 568 950; x_wconf 96'>Exclusive</span>
      <span class='ocrx_word' id='word_1_117' title='bbox 581 913 756 950; x_wconf 96'>real-time</span>
@@ -190,7 +190,7 @@
      <span class='ocrx_word' id='word_1_121' title='bbox 1266 914 1400 958; x_wconf 96'>editing</span>
      <span class='ocrx_word' id='word_1_122' title='bbox 1414 915 1535 950; x_wconf 95'>FAST.</span>
     </span>
-     <span class='ocr_line' id='line_1_14' title="bbox 349 971 2030 1016; baseline 0.001 -10; x_size 44; x_descenders 8; x_ascenders 11">
+     <span class='ocr_header' id='line_1_14' title="bbox 349 971 2030 1016; baseline 0.001 -10; x_size 44; x_descenders 8; x_ascenders 11">
      <span class='ocrx_word' id='word_1_123' title='bbox 349 979 367 997; x_wconf 0'>*</span>
      <span class='ocrx_word' id='word_1_124' title='bbox 382 971 568 1007; x_wconf 95'>Exclusive</span>
      <span class='ocrx_word' id='word_1_125' title='bbox 582 972 773 1007; x_wconf 96'>REPEAT</span>
@@ -216,11 +216,11 @@
   </div>
   <div class='ocr_carea' id='block_1_9' title="bbox 349 1080 2174 1125">
    <p class='ocr_par' id='par_1_11' lang='eng' title="bbox 349 1080 2174 1125">
-     <span class='ocr_line' id='line_1_16' title="bbox 349 1080 2174 1125; baseline 0.001 -11; x_size 45; x_descenders 9; x_ascenders 11">
+     <span class='ocr_header' id='line_1_16' title="bbox 349 1080 2174 1125; baseline 0.001 -11; x_size 45; x_descenders 9; x_ascenders 11">
      <span class='ocrx_word' id='word_1_137' title='bbox 349 1087 367 1105; x_wconf 80'>¢</span>
      <span class='ocrx_word' id='word_1_138' title='bbox 382 1080 567 1115; x_wconf 95'>TIMING</span>
-      <span class='ocrx_word' id='word_1_139' title='bbox 582 1080 870 1116; x_wconf 95'>CORRECTION</span>
-      <span class='ocrx_word' id='word_1_140' title='bbox 872 1080 1041 1116; x_wconf 96'>works</span>
+      <span class='ocrx_word' id='word_1_139' title='bbox 582 1080 908 1116; x_wconf 95'>CORRECTION</span>
+      <span class='ocrx_word' id='word_1_140' title='bbox 921 1080 1041 1116; x_wconf 96'>works</span>
      <span class='ocrx_word' id='word_1_141' title='bbox 1056 1080 1186 1124; x_wconf 96'>during</span>
      <span class='ocrx_word' id='word_1_142' title='bbox 1199 1080 1378 1124; x_wconf 96'>playback</span>
      <span class='ocrx_word' id='word_1_143' title='bbox 1392 1080 1466 1116; x_wconf 96'>and</span>
@@ -233,11 +233,11 @@
   </div>
   <div class='ocr_carea' id='block_1_10' title="bbox 349 1137 1287 1182">
    <p class='ocr_par' id='par_1_12' lang='eng' title="bbox 349 1137 1287 1182">
-     <span class='ocr_line' id='line_1_17' title="bbox 349 1137 1287 1182; baseline 0.001 -9; x_size 45; x_descenders 9; x_ascenders 11">
+     <span class='ocr_textfloat' id='line_1_17' title="bbox 349 1137 1287 1182; baseline 0.001 -9; x_size 45; x_descenders 9; x_ascenders 11">
      <span class='ocrx_word' id='word_1_148' title='bbox 349 1145 367 1163; x_wconf 80'>¢</span>
      <span class='ocrx_word' id='word_1_149' title='bbox 382 1137 560 1182; x_wconf 95'>Optional</span>
-      <span class='ocrx_word' id='word_1_150' title='bbox 575 1138 708 1174; x_wconf 96'>SMPTE</span>
-      <span class='ocrx_word' id='word_1_151' title='bbox 709 1138 839 1174; x_wconf 96'>time</span>
+      <span class='ocrx_word' id='word_1_150' title='bbox 575 1138 739 1174; x_wconf 96'>SMPTE</span>
+      <span class='ocrx_word' id='word_1_151' title='bbox 752 1138 839 1174; x_wconf 96'>time</span>
      <span class='ocrx_word' id='word_1_152' title='bbox 853 1138 945 1174; x_wconf 95'>code</span>
      <span class='ocrx_word' id='word_1_153' title='bbox 959 1138 1287 1182; x_wconf 96'>synchronization.</span>
     </span>
@@ -278,9 +278,9 @@
      <span class='ocrx_word' id='word_1_170' title='bbox 346 1379 411 1406; x_wconf 96'>then</span>
      <span class='ocrx_word' id='word_1_171' title='bbox 422 1378 483 1412; x_wconf 96'>play</span>
      <span class='ocrx_word' id='word_1_172' title='bbox 493 1387 562 1412; x_wconf 96'>your</span>
-      <span class='ocrx_word' id='word_1_173' title='bbox 572 1379 646 1405; x_wconf 96'>MIDI</span>
-      <span class='ocrx_word' id='word_1_174' title='bbox 649 1379 792 1412; x_wconf 96'>keyboard</span>
-      <span class='ocrx_word' id='word_1_175' title='bbox 792 1379 848 1406; x_wconf 95'>in</span>
+      <span class='ocrx_word' id='word_1_173' title='bbox 572 1379 659 1405; x_wconf 96'>MIDI</span>
+      <span class='ocrx_word' id='word_1_174' title='bbox 671 1379 810 1412; x_wconf 96'>keyboard</span>
+      <span class='ocrx_word' id='word_1_175' title='bbox 821 1379 848 1406; x_wconf 95'>in</span>
      <span class='ocrx_word' id='word_1_176' title='bbox 858 1379 923 1406; x_wconf 95'>time</span>
      <span class='ocrx_word' id='word_1_177' title='bbox 934 1384 963 1406; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_178' title='bbox 974 1379 1019 1406; x_wconf 93'>the</span>
@@ -294,14 +294,14 @@
      <span class='ocrx_word' id='word_1_184' title='bbox 676 1426 810 1452; x_wconf 96'>sequence</span>
      <span class='ocrx_word' id='word_1_185' title='bbox 821 1419 901 1452; x_wconf 96'>loops</span>
      <span class='ocrx_word' id='word_1_186' title='bbox 912 1419 983 1446; x_wconf 96'>back</span>
-      <span class='ocrx_word' id='word_1_187' title='bbox 995 1427 1082 1446; x_wconf 96'>around</span>
-      <span class='ocrx_word' id='word_1_188' title='bbox 1084 1419 1141 1446; x_wconf 96'>to</span>
-      <span class='ocrx_word' id='word_1_189' title='bbox 1152 1419 1189 1446; x_wconf 96'>bar</span>
-      <span class='ocrx_word' id='word_1_190' title='bbox 1189 1419 1232 1450; x_wconf 74'>1,</span>
+      <span class='ocrx_word' id='word_1_187' title='bbox 995 1419 1101 1446; x_wconf 96'>around</span>
+      <span class='ocrx_word' id='word_1_188' title='bbox 1112 1423 1141 1446; x_wconf 96'>to</span>
+      <span class='ocrx_word' id='word_1_189' title='bbox 1152 1419 1201 1446; x_wconf 96'>bar</span>
+      <span class='ocrx_word' id='word_1_190' title='bbox 1213 1419 1232 1450; x_wconf 74'>1,</span>
     </span>
     <span class='ocr_line' id='line_1_23' title="bbox 346 1457 1223 1491; baseline 0.001 -7; x_size 34; x_descenders 7; x_ascenders 8">
-      <span class='ocrx_word' id='word_1_191' title='bbox 346 1465 400 1490; x_wconf 14'>you’</span>
-      <span class='ocrx_word' id='word_1_192' title='bbox 404 1457 430 1484; x_wconf 14'>ll</span>
+      <span class='ocrx_word' id='word_1_191' title='bbox 346 1457 430 1490; x_wconf 14'>you’</span>
+      <span class='ocrx_word' id='word_1_192' title='bbox 406 1453 436 1496; x_wconf 14'>ll</span>
      <span class='ocrx_word' id='word_1_193' title='bbox 441 1457 506 1485; x_wconf 96'>hear</span>
      <span class='ocrx_word' id='word_1_194' title='bbox 517 1458 590 1485; x_wconf 96'>what</span>
      <span class='ocrx_word' id='word_1_195' title='bbox 600 1466 654 1491; x_wconf 93'>you</span>
@@ -316,7 +316,7 @@
   </div>
   <div class='ocr_carea' id='block_1_13' title="bbox 346 1497 1245 1531">
    <p class='ocr_par' id='par_1_16' lang='eng' title="bbox 346 1497 1245 1531">
-     <span class='ocr_line' id='line_1_24' title="bbox 346 1497 1245 1531; baseline 0.001 -7; x_size 35; x_descenders 7; x_ascenders 9">
+     <span class='ocr_textfloat' id='line_1_24' title="bbox 346 1497 1245 1531; baseline 0.001 -7; x_size 35; x_descenders 7; x_ascenders 9">
      <span class='ocrx_word' id='word_1_202' title='bbox 346 1497 494 1524; x_wconf 96'>corrected!</span>
      <span class='ocrx_word' id='word_1_203' title='bbox 508 1497 628 1530; x_wconf 96'>(Timing</span>
      <span class='ocrx_word' id='word_1_204' title='bbox 638 1497 791 1525; x_wconf 95'>correction</span>
@@ -343,8 +343,8 @@
      <span class='ocrx_word' id='word_1_219' title='bbox 1111 1537 1186 1564; x_wconf 96'>track</span>
     </span>
     <span class='ocr_line' id='line_1_26' title="bbox 347 1575 1052 1610; baseline 0.001 -8; x_size 34; x_descenders 7; x_ascenders 8">
-      <span class='ocrx_word' id='word_1_220' title='bbox 347 1591 381 1594; x_wconf 0'>—</span>
-      <span class='ocrx_word' id='word_1_221' title='bbox 382 1575 495 1609; x_wconf 0'>existing</span>
+      <span class='ocrx_word' id='word_1_220' title='bbox 347 1591 372 1594; x_wconf 0'>—</span>
+      <span class='ocrx_word' id='word_1_221' title='bbox 371 1575 495 1609; x_wconf 0'>existing</span>
      <span class='ocrx_word' id='word_1_222' title='bbox 505 1580 582 1603; x_wconf 96'>notes</span>
      <span class='ocrx_word' id='word_1_223' title='bbox 593 1584 637 1603; x_wconf 96'>are</span>
      <span class='ocrx_word' id='word_1_224' title='bbox 648 1580 696 1603; x_wconf 97'>not</span>
@@ -358,10 +358,10 @@
     <span class='ocr_line' id='line_1_27' title="bbox 384 1616 1199 1648; baseline 0.001 -6; x_size 32; x_descenders 5; x_ascenders 8">
      <span class='ocrx_word' id='word_1_228' title='bbox 384 1616 471 1642; x_wconf 96'>FAST</span>
      <span class='ocrx_word' id='word_1_229' title='bbox 481 1616 671 1648; x_wconf 96'>FORWARD,</span>
-      <span class='ocrx_word' id='word_1_230' title='bbox 684 1617 838 1643; x_wconf 95'>REWIND,</span>
-      <span class='ocrx_word' id='word_1_231' title='bbox 839 1616 912 1648; x_wconf 95'>and</span>
-      <span class='ocrx_word' id='word_1_232' title='bbox 924 1616 1045 1643; x_wconf 96'>LOCATE</span>
-      <span class='ocrx_word' id='word_1_233' title='bbox 1046 1616 1199 1643; x_wconf 95'>controls</span>
+      <span class='ocrx_word' id='word_1_230' title='bbox 684 1617 844 1648; x_wconf 95'>REWIND,</span>
+      <span class='ocrx_word' id='word_1_231' title='bbox 857 1616 912 1643; x_wconf 95'>and</span>
+      <span class='ocrx_word' id='word_1_232' title='bbox 924 1616 1068 1643; x_wconf 96'>LOCATE</span>
+      <span class='ocrx_word' id='word_1_233' title='bbox 1079 1616 1199 1643; x_wconf 95'>controls</span>
     </span>
     <span class='ocr_line' id='line_1_28' title="bbox 346 1655 1202 1689; baseline 0 -7; x_size 34; x_descenders 6; x_ascenders 9">
      <span class='ocrx_word' id='word_1_234' title='bbox 346 1663 409 1688; x_wconf 92'>may</span>
@@ -385,8 +385,8 @@
      <span class='ocrx_word' id='word_1_250' title='bbox 860 1696 897 1722; x_wconf 93'>To</span>
      <span class='ocrx_word' id='word_1_251' title='bbox 908 1695 1028 1722; x_wconf 93'>overdub</span>
      <span class='ocrx_word' id='word_1_252' title='bbox 1039 1703 1056 1722; x_wconf 96'>a</span>
-      <span class='ocrx_word' id='word_1_253' title='bbox 1066 1703 1099 1722; x_wconf 96'>new</span>
-      <span class='ocrx_word' id='word_1_254' title='bbox 1100 1699 1204 1728; x_wconf 96'>part,</span>
+      <span class='ocrx_word' id='word_1_253' title='bbox 1066 1703 1125 1722; x_wconf 96'>new</span>
+      <span class='ocrx_word' id='word_1_254' title='bbox 1135 1699 1204 1728; x_wconf 96'>part,</span>
     </span>
     <span class='ocr_line' id='line_1_30' title="bbox 347 1733 1150 1768; baseline 0.001 -8; x_size 35; x_descenders 7; x_ascenders 9">
      <span class='ocrx_word' id='word_1_255' title='bbox 347 1733 426 1761; x_wconf 97'>select</span>
@@ -401,8 +401,8 @@
     <span class='ocr_line' id='line_1_31' title="bbox 346 1773 1203 1808; baseline 0.001 -8; x_size 33; x_descenders 6; x_ascenders 8">
      <span class='ocrx_word' id='word_1_263' title='bbox 346 1774 448 1806; x_wconf 96'>record,</span>
      <span class='ocrx_word' id='word_1_264' title='bbox 460 1774 506 1801; x_wconf 97'>the</span>
-      <span class='ocrx_word' id='word_1_265' title='bbox 517 1773 577 1801; x_wconf 96'>first</span>
-      <span class='ocrx_word' id='word_1_266' title='bbox 581 1774 662 1801; x_wconf 96'>track</span>
+      <span class='ocrx_word' id='word_1_265' title='bbox 503 1769 577 1812; x_wconf 96'>first</span>
+      <span class='ocrx_word' id='word_1_266' title='bbox 581 1774 658 1801; x_wconf 96'>track</span>
      <span class='ocrx_word' id='word_1_267' title='bbox 673 1774 726 1801; x_wconf 96'>will</span>
      <span class='ocrx_word' id='word_1_268' title='bbox 736 1774 799 1807; x_wconf 96'>play</span>
      <span class='ocrx_word' id='word_1_269' title='bbox 809 1774 836 1801; x_wconf 96'>in</span>
@@ -412,12 +412,12 @@
      <span class='ocrx_word' id='word_1_273' title='bbox 1148 1782 1203 1807; x_wconf 96'>you</span>
     </span>
     <span class='ocr_line' id='line_1_32' title="bbox 346 1813 1191 1847; baseline 0.002 -8; x_size 33; x_descenders 5; x_ascenders 9">
-      <span class='ocrx_word' id='word_1_274' title='bbox 346 1813 431 1840; x_wconf 95'>MUTE</span>
-      <span class='ocrx_word' id='word_1_275' title='bbox 431 1813 492 1845; x_wconf 95'>it,</span>
+      <span class='ocrx_word' id='word_1_274' title='bbox 346 1813 454 1840; x_wconf 95'>MUTE</span>
+      <span class='ocrx_word' id='word_1_275' title='bbox 464 1813 492 1845; x_wconf 95'>it,</span>
      <span class='ocrx_word' id='word_1_276' title='bbox 505 1821 537 1840; x_wconf 95'>or</span>
      <span class='ocrx_word' id='word_1_277' title='bbox 547 1813 642 1840; x_wconf 95'>SOLO</span>
-      <span class='ocrx_word' id='word_1_278' title='bbox 653 1814 756 1841; x_wconf 95'>another</span>
-      <span class='ocrx_word' id='word_1_279' title='bbox 757 1814 875 1847; x_wconf 94'>track).</span>
+      <span class='ocrx_word' id='word_1_278' title='bbox 653 1814 769 1841; x_wconf 95'>another</span>
+      <span class='ocrx_word' id='word_1_279' title='bbox 779 1814 875 1847; x_wconf 94'>track).</span>
      <span class='ocrx_word' id='word_1_280' title='bbox 889 1814 920 1840; x_wconf 96'>In</span>
      <span class='ocrx_word' id='word_1_281' title='bbox 930 1813 984 1841; x_wconf 96'>this</span>
      <span class='ocrx_word' id='word_1_282' title='bbox 995 1822 1057 1847; x_wconf 96'>way,</span>
@@ -431,8 +431,8 @@
      <span class='ocrx_word' id='word_1_288' title='bbox 518 1853 552 1879; x_wconf 96'>be</span>
      <span class='ocrx_word' id='word_1_289' title='bbox 562 1853 748 1880; x_wconf 96'>overdubbed!</span>
      <span class='ocrx_word' id='word_1_290' title='bbox 761 1853 808 1880; x_wconf 94'>All</span>
-      <span class='ocrx_word' id='word_1_291' title='bbox 819 1854 892 1880; x_wconf 96'>MIDI</span>
-      <span class='ocrx_word' id='word_1_292' title='bbox 895 1853 1011 1880; x_wconf 96'>effects</span>
+      <span class='ocrx_word' id='word_1_291' title='bbox 819 1854 905 1880; x_wconf 96'>MIDI</span>
+      <span class='ocrx_word' id='word_1_292' title='bbox 917 1853 1011 1880; x_wconf 96'>effects</span>
      <span class='ocrx_word' id='word_1_293' title='bbox 1022 1861 1067 1880; x_wconf 96'>are</span>
      <span class='ocrx_word' id='word_1_294' title='bbox 1076 1853 1205 1880; x_wconf 96'>recorded</span>
     </span>
@@ -440,8 +440,8 @@
      <span class='ocrx_word' id='word_1_295' title='bbox 346 1891 485 1925; x_wconf 96'>including</span>
      <span class='ocrx_word' id='word_1_296' title='bbox 495 1891 570 1925; x_wconf 96'>pitch</span>
      <span class='ocrx_word' id='word_1_297' title='bbox 580 1892 663 1924; x_wconf 96'>bend,</span>
-      <span class='ocrx_word' id='word_1_298' title='bbox 675 1892 850 1920; x_wconf 96'>modulation,</span>
-      <span class='ocrx_word' id='word_1_299' title='bbox 854 1892 991 1926; x_wconf 93'>velocity,</span>
+      <span class='ocrx_word' id='word_1_298' title='bbox 675 1892 859 1924; x_wconf 96'>modulation,</span>
+      <span class='ocrx_word' id='word_1_299' title='bbox 872 1892 991 1926; x_wconf 93'>velocity,</span>
      <span class='ocrx_word' id='word_1_300' title='bbox 1004 1892 1168 1924; x_wconf 92'>aftertouch,</span>
     </span>
     <span class='ocr_line' id='line_1_35' title="bbox 346 1931 895 1965; baseline 0.002 -7; x_size 33; x_descenders 6; x_ascenders 8">
@@ -465,13 +465,13 @@
      <span class='ocrx_word' id='word_1_307' title='bbox 383 2050 419 2076; x_wconf 96'>To</span>
      <span class='ocrx_word' id='word_1_308' title='bbox 430 2057 503 2076; x_wconf 95'>erase</span>
      <span class='ocrx_word' id='word_1_309' title='bbox 514 2058 530 2077; x_wconf 96'>a</span>
-      <span class='ocrx_word' id='word_1_310' title='bbox 540 2058 617 2077; x_wconf 96'>wrong</span>
-      <span class='ocrx_word' id='word_1_311' title='bbox 618 2054 717 2083; x_wconf 96'>note,</span>
+      <span class='ocrx_word' id='word_1_310' title='bbox 540 2058 634 2083; x_wconf 96'>wrong</span>
+      <span class='ocrx_word' id='word_1_311' title='bbox 644 2054 717 2082; x_wconf 96'>note,</span>
      <span class='ocrx_word' id='word_1_312' title='bbox 729 2050 829 2083; x_wconf 96'>simply</span>
      <span class='ocrx_word' id='word_1_313' title='bbox 839 2050 905 2077; x_wconf 96'>hold</span>
-      <span class='ocrx_word' id='word_1_314' title='bbox 916 2051 1013 2077; x_wconf 96'>ERASE</span>
-      <span class='ocrx_word' id='word_1_315' title='bbox 1015 2051 1083 2077; x_wconf 96'>and</span>
-      <span class='ocrx_word' id='word_1_316' title='bbox 1085 2050 1186 2084; x_wconf 96'>press</span>
+      <span class='ocrx_word' id='word_1_314' title='bbox 916 2051 1037 2077; x_wconf 96'>ERASE</span>
+      <span class='ocrx_word' id='word_1_315' title='bbox 1048 2050 1103 2077; x_wconf 96'>and</span>
+      <span class='ocrx_word' id='word_1_316' title='bbox 1113 2059 1186 2084; x_wconf 96'>press</span>
     </span>
     <span class='ocr_line' id='line_1_38' title="bbox 346 2089 1212 2124; baseline 0.002 -8; x_size 33; x_descenders 6; x_ascenders 8">
      <span class='ocrx_word' id='word_1_317' title='bbox 346 2089 391 2116; x_wconf 96'>the</span>
@@ -480,16 +480,16 @@
      <span class='ocrx_word' id='word_1_320' title='bbox 515 2090 549 2117; x_wconf 97'>be</span>
      <span class='ocrx_word' id='word_1_321' title='bbox 559 2090 652 2117; x_wconf 96'>erased</span>
      <span class='ocrx_word' id='word_1_322' title='bbox 661 2090 718 2123; x_wconf 96'>just</span>
-      <span class='ocrx_word' id='word_1_323' title='bbox 729 2090 808 2117; x_wconf 96'>before</span>
-      <span class='ocrx_word' id='word_1_324' title='bbox 808 2090 852 2117; x_wconf 96'>it</span>
+      <span class='ocrx_word' id='word_1_323' title='bbox 729 2090 822 2117; x_wconf 96'>before</span>
+      <span class='ocrx_word' id='word_1_324' title='bbox 833 2090 852 2117; x_wconf 96'>it</span>
      <span class='ocrx_word' id='word_1_325' title='bbox 862 2090 937 2124; x_wconf 96'>plays</span>
      <span class='ocrx_word' id='word_1_326' title='bbox 947 2090 975 2117; x_wconf 96'>in</span>
      <span class='ocrx_word' id='word_1_327' title='bbox 986 2090 1032 2118; x_wconf 93'>the</span>
      <span class='ocrx_word' id='word_1_328' title='bbox 1043 2098 1212 2124; x_wconf 88'>sequence—</span>
     </span>
     <span class='ocr_line' id='line_1_39' title="bbox 346 2129 1134 2163; baseline 0.003 -8; x_size 34; x_descenders 7; x_ascenders 8">
-      <span class='ocrx_word' id='word_1_329' title='bbox 346 2129 406 2156; x_wconf 96'>when</span>
-      <span class='ocrx_word' id='word_1_330' title='bbox 407 2129 531 2162; x_wconf 96'>played</span>
+      <span class='ocrx_word' id='word_1_329' title='bbox 346 2129 425 2156; x_wconf 96'>when</span>
+      <span class='ocrx_word' id='word_1_330' title='bbox 435 2129 531 2162; x_wconf 96'>played</span>
      <span class='ocrx_word' id='word_1_331' title='bbox 542 2129 621 2161; x_wconf 96'>back,</span>
      <span class='ocrx_word' id='word_1_332' title='bbox 633 2129 652 2156; x_wconf 96'>it</span>
      <span class='ocrx_word' id='word_1_333' title='bbox 663 2129 716 2156; x_wconf 96'>will</span>
@@ -512,15 +512,15 @@
      <span class='ocrx_word' id='word_1_344' title='bbox 749 2169 829 2203; x_wconf 96'>using</span>
      <span class='ocrx_word' id='word_1_345' title='bbox 839 2169 885 2196; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_346' title='bbox 896 2170 1031 2196; x_wconf 96'>SINGLE</span>
-      <span class='ocrx_word' id='word_1_347' title='bbox 1042 2170 1107 2196; x_wconf 91'>STEP</span>
-      <span class='ocrx_word' id='word_1_348' title='bbox 1109 2169 1220 2196; x_wconf 91'>func-</span>
+      <span class='ocrx_word' id='word_1_347' title='bbox 1042 2170 1131 2196; x_wconf 91'>STEP</span>
+      <span class='ocrx_word' id='word_1_348' title='bbox 1143 2169 1220 2196; x_wconf 91'>func-</span>
     </span>
     <span class='ocr_line' id='line_1_41' title="bbox 345 2207 1228 2242; baseline 0.002 -8; x_size 35; x_descenders 7; x_ascenders 9">
      <span class='ocrx_word' id='word_1_349' title='bbox 345 2207 412 2234; x_wconf 96'>tion.</span>
      <span class='ocrx_word' id='word_1_350' title='bbox 424 2208 461 2235; x_wconf 93'>To</span>
      <span class='ocrx_word' id='word_1_351' title='bbox 472 2208 592 2235; x_wconf 91'>overdub</span>
-      <span class='ocrx_word' id='word_1_352' title='bbox 603 2212 667 2235; x_wconf 96'>notes</span>
-      <span class='ocrx_word' id='word_1_353' title='bbox 668 2212 718 2235; x_wconf 96'>at</span>
+      <span class='ocrx_word' id='word_1_352' title='bbox 603 2212 680 2235; x_wconf 96'>notes</span>
+      <span class='ocrx_word' id='word_1_353' title='bbox 691 2212 718 2235; x_wconf 96'>at</span>
      <span class='ocrx_word' id='word_1_354' title='bbox 729 2208 841 2242; x_wconf 96'>specific</span>
      <span class='ocrx_word' id='word_1_355' title='bbox 851 2209 943 2242; x_wconf 97'>points</span>
      <span class='ocrx_word' id='word_1_356' title='bbox 955 2208 1049 2236; x_wconf 96'>within</span>
@@ -544,10 +544,10 @@
      <span class='ocrx_word' id='word_1_362' title='bbox 1404 1297 1452 1316; x_wconf 96'>use</span>
      <span class='ocrx_word' id='word_1_363' title='bbox 1463 1290 1615 1321; x_wconf 96'>LOCATE,</span>
      <span class='ocrx_word' id='word_1_364' title='bbox 1628 1290 1716 1316; x_wconf 96'>FAST</span>
-      <span class='ocrx_word' id='word_1_365' title='bbox 1726 1289 1910 1316; x_wconf 95'>FORWARD,</span>
-      <span class='ocrx_word' id='word_1_366' title='bbox 1911 1297 1960 1321; x_wconf 96'>or</span>
-      <span class='ocrx_word' id='word_1_367' title='bbox 1972 1290 2098 1316; x_wconf 95'>REWIND</span>
-      <span class='ocrx_word' id='word_1_368' title='bbox 2100 1290 2165 1317; x_wconf 95'>to</span>
+      <span class='ocrx_word' id='word_1_365' title='bbox 1726 1289 1917 1321; x_wconf 95'>FORWARD,</span>
+      <span class='ocrx_word' id='word_1_366' title='bbox 1929 1297 1960 1317; x_wconf 96'>or</span>
+      <span class='ocrx_word' id='word_1_367' title='bbox 1972 1290 2126 1316; x_wconf 95'>REWIND</span>
+      <span class='ocrx_word' id='word_1_368' title='bbox 2136 1294 2165 1317; x_wconf 95'>to</span>
     </span>
     <span class='ocr_line' id='line_1_44' title="bbox 1297 1328 2033 1362; baseline 0.001 -7; x_size 32; x_descenders 5; x_ascenders 8">
      <span class='ocrx_word' id='word_1_369' title='bbox 1297 1328 1356 1355; x_wconf 96'>find</span>
@@ -564,8 +564,8 @@
    <p class='ocr_par' id='par_1_24' lang='eng' title="bbox 1295 1368 2160 1593">
     <span class='ocr_line' id='line_1_45' title="bbox 1332 1368 2160 1402; baseline 0.002 -8; x_size 34; x_descenders 7; x_ascenders 8">
      <span class='ocrx_word' id='word_1_377' title='bbox 1332 1368 1391 1395; x_wconf 93'>The</span>
-      <span class='ocrx_word' id='word_1_378' title='bbox 1402 1368 1626 1395; x_wconf 91'>INSERT/COPY</span>
-      <span class='ocrx_word' id='word_1_379' title='bbox 1626 1368 1789 1395; x_wconf 96'>function</span>
+      <span class='ocrx_word' id='word_1_378' title='bbox 1402 1368 1650 1395; x_wconf 91'>INSERT/COPY</span>
+      <span class='ocrx_word' id='word_1_379' title='bbox 1662 1368 1789 1395; x_wconf 96'>function</span>
      <span class='ocrx_word' id='word_1_380' title='bbox 1800 1368 1893 1395; x_wconf 96'>allows</span>
      <span class='ocrx_word' id='word_1_381' title='bbox 1904 1376 1958 1402; x_wconf 96'>you</span>
      <span class='ocrx_word' id='word_1_382' title='bbox 1968 1373 1997 1395; x_wconf 96'>to</span>
@@ -580,8 +580,8 @@
      <span class='ocrx_word' id='word_1_389' title='bbox 1616 1407 1796 1435; x_wconf 91'>another—in</span>
      <span class='ocrx_word' id='word_1_390' title='bbox 1806 1408 1852 1435; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_391' title='bbox 1863 1416 1937 1435; x_wconf 96'>same</span>
-      <span class='ocrx_word' id='word_1_392' title='bbox 1948 1416 2067 1441; x_wconf 96'>sequence</span>
-      <span class='ocrx_word' id='word_1_393' title='bbox 2068 1416 2125 1435; x_wconf 96'>or</span>
+      <span class='ocrx_word' id='word_1_392' title='bbox 1948 1416 2083 1441; x_wconf 96'>sequence</span>
+      <span class='ocrx_word' id='word_1_393' title='bbox 2093 1416 2125 1435; x_wconf 96'>or</span>
      <span class='ocrx_word' id='word_1_394' title='bbox 2135 1416 2151 1435; x_wconf 96'>a</span>
     </span>
     <span class='ocr_line' id='line_1_47' title="bbox 1296 1447 2160 1481; baseline 0.001 -7; x_size 34; x_descenders 7; x_ascenders 8">
@@ -603,15 +603,15 @@
      <span class='ocrx_word' id='word_1_408' title='bbox 1449 1487 1571 1514; x_wconf 96'>between</span>
      <span class='ocrx_word' id='word_1_409' title='bbox 1582 1487 1628 1514; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_410' title='bbox 1638 1487 1740 1514; x_wconf 96'>second</span>
-      <span class='ocrx_word' id='word_1_411' title='bbox 1751 1487 1838 1514; x_wconf 96'>chorus</span>
-      <span class='ocrx_word' id='word_1_412' title='bbox 1841 1495 1899 1514; x_wconf 96'>and</span>
-      <span class='ocrx_word' id='word_1_413' title='bbox 1901 1487 1975 1514; x_wconf 96'>the</span>
+      <span class='ocrx_word' id='word_1_411' title='bbox 1751 1487 1852 1514; x_wconf 96'>chorus</span>
+      <span class='ocrx_word' id='word_1_412' title='bbox 1863 1487 1919 1514; x_wconf 96'>and</span>
+      <span class='ocrx_word' id='word_1_413' title='bbox 1929 1487 1975 1514; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_414' title='bbox 1985 1487 2087 1521; x_wconf 96'>bridge.</span>
     </span>
     <span class='ocr_line' id='line_1_49' title="bbox 1296 1527 2047 1560; baseline 0.003 -8; x_size 32; x_descenders 6; x_ascenders 7">
      <span class='ocrx_word' id='word_1_415' title='bbox 1296 1527 1441 1553; x_wconf 95'>DELETE</span>
-      <span class='ocrx_word' id='word_1_416' title='bbox 1453 1527 1527 1553; x_wconf 96'>BARS</span>
-      <span class='ocrx_word' id='word_1_417' title='bbox 1529 1527 1681 1559; x_wconf 96'>operates</span>
+      <span class='ocrx_word' id='word_1_416' title='bbox 1453 1527 1546 1553; x_wconf 96'>BARS</span>
+      <span class='ocrx_word' id='word_1_417' title='bbox 1557 1531 1681 1559; x_wconf 96'>operates</span>
      <span class='ocrx_word' id='word_1_418' title='bbox 1691 1527 1737 1553; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_419' title='bbox 1748 1535 1823 1554; x_wconf 96'>same</span>
      <span class='ocrx_word' id='word_1_420' title='bbox 1833 1535 1891 1560; x_wconf 96'>way</span>
@@ -619,8 +619,8 @@
      <span class='ocrx_word' id='word_1_422' title='bbox 1940 1535 2047 1554; x_wconf 96'>remove</span>
     </span>
     <span class='ocr_line' id='line_1_50' title="bbox 1295 1565 1577 1593; baseline 0.004 -1; x_size 34.748871; x_descenders 6.7488689; x_ascenders 9">
-      <span class='ocrx_word' id='word_1_423' title='bbox 1295 1569 1422 1592; x_wconf 96'>unwanted</span>
-      <span class='ocrx_word' id='word_1_424' title='bbox 1423 1565 1577 1593; x_wconf 95'>sections,</span>
+      <span class='ocrx_word' id='word_1_423' title='bbox 1295 1565 1441 1592; x_wconf 96'>unwanted</span>
+      <span class='ocrx_word' id='word_1_424' title='bbox 1452 1565 1577 1593; x_wconf 95'>sections,</span>
     </span>
    </p>
   </div>
@@ -636,12 +636,12 @@
    <p class='ocr_par' id='par_1_26' lang='eng' title="bbox 1295 1690 2215 1960">
     <span class='ocr_line' id='line_1_52' title="bbox 1333 1690 2146 1723; baseline 0 -6; x_size 33; x_descenders 6; x_ascenders 8">
      <span class='ocrx_word' id='word_1_428' title='bbox 1333 1690 1394 1717; x_wconf 96'>One</span>
-      <span class='ocrx_word' id='word_1_429' title='bbox 1404 1698 1446 1717; x_wconf 96'>way</span>
-      <span class='ocrx_word' id='word_1_430' title='bbox 1445 1694 1500 1723; x_wconf 96'>to</span>
+      <span class='ocrx_word' id='word_1_429' title='bbox 1404 1698 1462 1723; x_wconf 96'>way</span>
+      <span class='ocrx_word' id='word_1_430' title='bbox 1472 1694 1500 1717; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_431' title='bbox 1511 1694 1598 1717; x_wconf 96'>create</span>
      <span class='ocrx_word' id='word_1_432' title='bbox 1608 1698 1625 1717; x_wconf 96'>a</span>
-      <span class='ocrx_word' id='word_1_433' title='bbox 1635 1698 1687 1717; x_wconf 95'>song</span>
-      <span class='ocrx_word' id='word_1_434' title='bbox 1688 1690 1736 1723; x_wconf 95'>is</span>
+      <span class='ocrx_word' id='word_1_433' title='bbox 1635 1698 1704 1723; x_wconf 95'>song</span>
+      <span class='ocrx_word' id='word_1_434' title='bbox 1715 1690 1736 1717; x_wconf 95'>is</span>
      <span class='ocrx_word' id='word_1_435' title='bbox 1747 1694 1776 1717; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_436' title='bbox 1787 1690 1880 1717; x_wconf 96'>record</span>
      <span class='ocrx_word' id='word_1_437' title='bbox 1891 1690 1958 1717; x_wconf 96'>each</span>
@@ -657,8 +657,8 @@
      <span class='ocrx_word' id='word_1_445' title='bbox 1592 1730 1644 1756; x_wconf 96'>999</span>
      <span class='ocrx_word' id='word_1_446' title='bbox 1654 1729 1738 1762; x_wconf 96'>bars).</span>
      <span class='ocrx_word' id='word_1_447' title='bbox 1751 1729 1878 1757; x_wconf 96'>Another</span>
-      <span class='ocrx_word' id='word_1_448' title='bbox 1888 1737 1930 1757; x_wconf 96'>way</span>
-      <span class='ocrx_word' id='word_1_449' title='bbox 1929 1729 1977 1762; x_wconf 96'>is</span>
+      <span class='ocrx_word' id='word_1_448' title='bbox 1888 1737 1945 1762; x_wconf 96'>way</span>
+      <span class='ocrx_word' id='word_1_449' title='bbox 1956 1729 1977 1757; x_wconf 96'>is</span>
      <span class='ocrx_word' id='word_1_450' title='bbox 1987 1733 2016 1757; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_451' title='bbox 2027 1729 2121 1757; x_wconf 96'>record</span>
     </span>
@@ -667,8 +667,8 @@
      <span class='ocrx_word' id='word_1_453' title='bbox 1373 1768 1448 1796; x_wconf 96'>basic</span>
      <span class='ocrx_word' id='word_1_454' title='bbox 1458 1768 1562 1796; x_wconf 96'>section</span>
      <span class='ocrx_word' id='word_1_455' title='bbox 1574 1769 1666 1802; x_wconf 96'>(verse,</span>
-      <span class='ocrx_word' id='word_1_456' title='bbox 1679 1769 1779 1796; x_wconf 96'>chorus,</span>
-      <span class='ocrx_word' id='word_1_457' title='bbox 1782 1769 1865 1802; x_wconf 96'>etc.)</span>
+      <span class='ocrx_word' id='word_1_456' title='bbox 1679 1769 1788 1801; x_wconf 96'>chorus,</span>
+      <span class='ocrx_word' id='word_1_457' title='bbox 1800 1769 1865 1802; x_wconf 96'>etc.)</span>
      <span class='ocrx_word' id='word_1_458' title='bbox 1876 1768 1904 1795; x_wconf 96'>in</span>
      <span class='ocrx_word' id='word_1_459' title='bbox 1914 1768 2066 1796; x_wconf 96'>individual</span>
     </span>
@@ -678,8 +678,8 @@
      <span class='ocrx_word' id='word_1_462' title='bbox 1538 1816 1587 1835; x_wconf 96'>use</span>
      <span class='ocrx_word' id='word_1_463' title='bbox 1597 1808 1643 1835; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_464' title='bbox 1653 1809 1799 1835; x_wconf 96'>CREATE</span>
-      <span class='ocrx_word' id='word_1_465' title='bbox 1810 1808 1883 1835; x_wconf 96'>SONG</span>
-      <span class='ocrx_word' id='word_1_466' title='bbox 1885 1808 2050 1836; x_wconf 96'>function</span>
+      <span class='ocrx_word' id='word_1_465' title='bbox 1810 1808 1911 1835; x_wconf 96'>SONG</span>
+      <span class='ocrx_word' id='word_1_466' title='bbox 1923 1808 2050 1836; x_wconf 96'>function</span>
      <span class='ocrx_word' id='word_1_467' title='bbox 2060 1812 2089 1835; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_468' title='bbox 2103 1808 2215 1836; x_wconf 93'>“chain”</span>
     </span>
@@ -687,14 +687,14 @@
      <span class='ocrx_word' id='word_1_469' title='bbox 1295 1848 1370 1874; x_wconf 96'>them</span>
      <span class='ocrx_word' id='word_1_470' title='bbox 1381 1848 1508 1881; x_wconf 95'>together.</span>
      <span class='ocrx_word' id='word_1_471' title='bbox 1521 1848 1667 1875; x_wconf 96'>CREATE</span>
-      <span class='ocrx_word' id='word_1_472' title='bbox 1678 1848 1751 1875; x_wconf 96'>SONG</span>
-      <span class='ocrx_word' id='word_1_473' title='bbox 1753 1847 1842 1874; x_wconf 96'>will</span>
+      <span class='ocrx_word' id='word_1_472' title='bbox 1678 1848 1779 1875; x_wconf 96'>SONG</span>
+      <span class='ocrx_word' id='word_1_473' title='bbox 1789 1847 1842 1874; x_wconf 96'>will</span>
      <span class='ocrx_word' id='word_1_474' title='bbox 1853 1848 1918 1875; x_wconf 96'>then</span>
      <span class='ocrx_word' id='word_1_475' title='bbox 1929 1848 2135 1881; x_wconf 96'>automatically</span>
     </span>
     <span class='ocr_line' id='line_1_57' title="bbox 1296 1887 2162 1920; baseline 0 -6; x_size 33; x_descenders 6; x_ascenders 8">
-      <span class='ocrx_word' id='word_1_476' title='bbox 1296 1895 1349 1920; x_wconf 96'>copy</span>
-      <span class='ocrx_word' id='word_1_477' title='bbox 1349 1887 1412 1920; x_wconf 96'>all</span>
+      <span class='ocrx_word' id='word_1_476' title='bbox 1296 1895 1366 1920; x_wconf 96'>copy</span>
+      <span class='ocrx_word' id='word_1_477' title='bbox 1377 1887 1412 1914; x_wconf 96'>all</span>
      <span class='ocrx_word' id='word_1_478' title='bbox 1422 1887 1468 1914; x_wconf 96'>the</span>
      <span class='ocrx_word' id='word_1_479' title='bbox 1478 1891 1552 1920; x_wconf 96'>parts</span>
      <span class='ocrx_word' id='word_1_480' title='bbox 1563 1887 1621 1914; x_wconf 95'>into</span>
@@ -714,8 +714,8 @@
      <span class='ocrx_word' id='word_1_492' title='bbox 1540 1926 1590 1953; x_wconf 96'>few</span>
      <span class='ocrx_word' id='word_1_493' title='bbox 1601 1927 1664 1953; x_wconf 96'>bars</span>
      <span class='ocrx_word' id='word_1_494' title='bbox 1675 1931 1704 1954; x_wconf 96'>to</span>
-      <span class='ocrx_word' id='word_1_495' title='bbox 1715 1935 1795 1960; x_wconf 96'>repeat</span>
-      <span class='ocrx_word' id='word_1_496' title='bbox 1795 1926 1955 1960; x_wconf 96'>infinitely,</span>
+      <span class='ocrx_word' id='word_1_495' title='bbox 1715 1931 1806 1960; x_wconf 96'>repeat</span>
+      <span class='ocrx_word' id='word_1_496' title='bbox 1816 1926 1955 1960; x_wconf 96'>infinitely,</span>
      <span class='ocrx_word' id='word_1_497' title='bbox 1968 1926 2011 1954; x_wconf 95'>for</span>
      <span class='ocrx_word' id='word_1_498' title='bbox 2022 1935 2038 1954; x_wconf 93'>a</span>
      <span class='ocrx_word' id='word_1_499' title='bbox 2049 1927 2169 1954; x_wconf 92'>fadeout.</span>
@@ -757,8 +757,8 @@
     </span>
     <span class='ocr_line' id='line_1_62' title="bbox 1293 2130 2156 2164; baseline 0 -7; x_size 34; x_descenders 7; x_ascenders 8">
      <span class='ocrx_word' id='word_1_522' title='bbox 1293 2130 1339 2157; x_wconf 93'>the</span>
-      <span class='ocrx_word' id='word_1_523' title='bbox 1350 2130 1562 2164; x_wconf 90'>LinnSequencer</span>
-      <span class='ocrx_word' id='word_1_524' title='bbox 1564 2130 1607 2157; x_wconf 97'>is</span>
+      <span class='ocrx_word' id='word_1_523' title='bbox 1350 2130 1576 2164; x_wconf 90'>LinnSequencer</span>
+      <span class='ocrx_word' id='word_1_524' title='bbox 1586 2130 1607 2157; x_wconf 97'>is</span>
      <span class='ocrx_word' id='word_1_525' title='bbox 1619 2130 1747 2164; x_wconf 96'>designed</span>
      <span class='ocrx_word' id='word_1_526' title='bbox 1758 2134 1787 2157; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_527' title='bbox 1798 2130 1834 2157; x_wconf 96'>let</span>
@@ -767,8 +767,8 @@
      <span class='ocrx_word' id='word_1_530' title='bbox 2063 2130 2156 2157; x_wconf 96'>record</span>
     </span>
     <span class='ocr_line' id='line_1_63' title="bbox 1294 2169 2145 2203; baseline 0 -6; x_size 33; x_descenders 6; x_ascenders 8">
-      <span class='ocrx_word' id='word_1_531' title='bbox 1294 2178 1330 2197; x_wconf 96'>and</span>
-      <span class='ocrx_word' id='word_1_532' title='bbox 1331 2169 1414 2197; x_wconf 96'>edit</span>
+      <span class='ocrx_word' id='word_1_531' title='bbox 1294 2170 1349 2197; x_wconf 96'>and</span>
+      <span class='ocrx_word' id='word_1_532' title='bbox 1360 2169 1414 2197; x_wconf 96'>edit</span>
      <span class='ocrx_word' id='word_1_533' title='bbox 1425 2170 1503 2197; x_wconf 96'>while</span>
      <span class='ocrx_word' id='word_1_534' title='bbox 1514 2170 1643 2203; x_wconf 96'>devoting</span>
      <span class='ocrx_word' id='word_1_535' title='bbox 1653 2178 1721 2203; x_wconf 96'>your</span>
@@ -792,7 +792,7 @@
   </div>
   <div class='ocr_carea' id='block_1_21' title="bbox 347 2343 2171 2378">
    <p class='ocr_par' id='par_1_29' lang='eng' title="bbox 347 2343 2171 2378">
-     <span class='ocr_line' id='line_1_65' title="bbox 347 2343 2171 2378; baseline 0.001 -8; x_size 34; x_descenders 7; x_ascenders 8">
+     <span class='ocr_header' id='line_1_65' title="bbox 347 2343 2171 2378; baseline 0.001 -8; x_size 34; x_descenders 7; x_ascenders 8">
      <span class='ocrx_word' id='word_1_549' title='bbox 347 2350 361 2363; x_wconf 58'>*</span>
      <span class='ocrx_word' id='word_1_550' title='bbox 373 2343 483 2377; x_wconf 96'>Simple,</span>
      <span class='ocrx_word' id='word_1_551' title='bbox 495 2352 559 2377; x_wconf 96'>easy</span>
@@ -806,8 +806,8 @@
      <span class='ocrx_word' id='word_1_559' title='bbox 1326 2345 1424 2378; x_wconf 97'>clearly</span>
      <span class='ocrx_word' id='word_1_560' title='bbox 1434 2345 1528 2378; x_wconf 96'>guides</span>
      <span class='ocrx_word' id='word_1_561' title='bbox 1539 2353 1594 2378; x_wconf 97'>you</span>
-      <span class='ocrx_word' id='word_1_562' title='bbox 1604 2345 1705 2378; x_wconf 96'>through</span>
-      <span class='ocrx_word' id='word_1_563' title='bbox 1706 2344 1770 2371; x_wconf 96'>all</span>
+      <span class='ocrx_word' id='word_1_562' title='bbox 1604 2345 1724 2378; x_wconf 96'>through</span>
+      <span class='ocrx_word' id='word_1_563' title='bbox 1735 2344 1770 2371; x_wconf 96'>all</span>
      <span class='ocrx_word' id='word_1_564' title='bbox 1781 2344 1947 2377; x_wconf 96'>operations.</span>
      <span class='ocrx_word' id='word_1_565' title='bbox 1961 2344 1989 2371; x_wconf 96'>If</span>
      <span class='ocrx_word' id='word_1_566' title='bbox 1997 2344 2112 2376; x_wconf 96'>needed,</span>
@@ -818,8 +818,8 @@
   <div class='ocr_carea' id='block_1_22' title="bbox 373 2381 1083 2415">
    <p class='ocr_par' id='par_1_30' lang='eng' title="bbox 373 2381 1083 2415">
     <span class='ocr_line' id='line_1_66' title="bbox 373 2381 1083 2415; baseline 0.003 -8; x_size 34; x_descenders 7; x_ascenders 8">
-      <span class='ocrx_word' id='word_1_568' title='bbox 373 2381 448 2407; x_wconf 96'>HELP</span>
-      <span class='ocrx_word' id='word_1_569' title='bbox 450 2381 583 2408; x_wconf 96'>button</span>
+      <span class='ocrx_word' id='word_1_568' title='bbox 373 2381 472 2407; x_wconf 96'>HELP</span>
+      <span class='ocrx_word' id='word_1_569' title='bbox 483 2381 583 2408; x_wconf 96'>button</span>
      <span class='ocrx_word' id='word_1_570' title='bbox 594 2381 711 2415; x_wconf 96'>displays</span>
      <span class='ocrx_word' id='word_1_571' title='bbox 722 2382 875 2409; x_wconf 96'>additional</span>
      <span class='ocrx_word' id='word_1_572' title='bbox 886 2382 1083 2415; x_wconf 96'>explanations.</span>
@@ -828,7 +828,7 @@
   </div>
   <div class='ocr_carea' id='block_1_23' title="bbox 347 2427 2145 2507">
    <p class='ocr_par' id='par_1_31' lang='eng' title="bbox 347 2427 2145 2507">
-     <span class='ocr_line' id='line_1_67' title="bbox 347 2427 1468 2461; baseline 0.002 -8; x_size 34; x_descenders 7; x_ascenders 8">
+     <span class='ocr_header' id='line_1_67' title="bbox 347 2427 1468 2461; baseline 0.002 -8; x_size 34; x_descenders 7; x_ascenders 8">
      <span class='ocrx_word' id='word_1_573' title='bbox 347 2432 361 2446; x_wconf 70'>*</span>
      <span class='ocrx_word' id='word_1_574' title='bbox 373 2427 612 2454; x_wconf 91'>Non-destructive</span>
      <span class='ocrx_word' id='word_1_575' title='bbox 622 2427 914 2461; x_wconf 89'>recording—existing</span>
@@ -839,14 +839,14 @@
      <span class='ocrx_word' id='word_1_580' title='bbox 1231 2428 1309 2455; x_wconf 96'>while</span>
      <span class='ocrx_word' id='word_1_581' title='bbox 1319 2428 1468 2461; x_wconf 92'>recording.</span>
     </span>
-     <span class='ocr_line' id='line_1_68' title="bbox 347 2473 2145 2507; baseline 0.001 -8; x_size 35; x_descenders 7; x_ascenders 9">
+     <span class='ocr_header' id='line_1_68' title="bbox 347 2473 2145 2507; baseline 0.001 -8; x_size 35; x_descenders 7; x_ascenders 9">
      <span class='ocrx_word' id='word_1_582' title='bbox 347 2478 361 2492; x_wconf 70'>¢</span>
      <span class='ocrx_word' id='word_1_583' title='bbox 372 2473 433 2500; x_wconf 93'>Two</span>
      <span class='ocrx_word' id='word_1_584' title='bbox 444 2473 689 2500; x_wconf 90'>FOOTSWITCH</span>
-      <span class='ocrx_word' id='word_1_585' title='bbox 701 2474 818 2500; x_wconf 95'>INPUTS</span>
-      <span class='ocrx_word' id='word_1_586' title='bbox 819 2474 894 2501; x_wconf 96'>may</span>
-      <span class='ocrx_word' id='word_1_587' title='bbox 893 2473 939 2507; x_wconf 96'>be</span>
-      <span class='ocrx_word' id='word_1_588' title='bbox 941 2473 1091 2507; x_wconf 96'>assigned</span>
+      <span class='ocrx_word' id='word_1_585' title='bbox 701 2474 837 2501; x_wconf 95'>INPUTS</span>
+      <span class='ocrx_word' id='word_1_586' title='bbox 848 2481 910 2507; x_wconf 96'>may</span>
+      <span class='ocrx_word' id='word_1_587' title='bbox 921 2473 955 2500; x_wconf 96'>be</span>
+      <span class='ocrx_word' id='word_1_588' title='bbox 966 2473 1091 2507; x_wconf 96'>assigned</span>
      <span class='ocrx_word' id='word_1_589' title='bbox 1101 2478 1130 2501; x_wconf 96'>to</span>
      <span class='ocrx_word' id='word_1_590' title='bbox 1141 2474 1271 2507; x_wconf 96'>remotely</span>
      <span class='ocrx_word' id='word_1_591' title='bbox 1281 2473 1387 2501; x_wconf 96'>control</span>
@@ -873,12 +873,12 @@
   </div>
   <div class='ocr_carea' id='block_1_25' title="bbox 347 2556 1768 2590">
    <p class='ocr_par' id='par_1_33' lang='eng' title="bbox 347 2556 1768 2590">
-     <span class='ocr_line' id='line_1_70' title="bbox 347 2556 1768 2590; baseline 0.001 -8; x_size 34; x_descenders 7; x_ascenders 8">
+     <span class='ocr_header' id='line_1_70' title="bbox 347 2556 1768 2590; baseline 0.001 -8; x_size 34; x_descenders 7; x_ascenders 8">
      <span class='ocrx_word' id='word_1_604' title='bbox 347 2561 361 2575; x_wconf 86'>¢</span>
      <span class='ocrx_word' id='word_1_605' title='bbox 372 2556 433 2583; x_wconf 85'>Iwo</span>
      <span class='ocrx_word' id='word_1_606' title='bbox 443 2556 612 2583; x_wconf 96'>TRIGGER</span>
-      <span class='ocrx_word' id='word_1_607' title='bbox 623 2556 778 2584; x_wconf 96'>OUTPUTS</span>
-      <span class='ocrx_word' id='word_1_608' title='bbox 780 2557 871 2590; x_wconf 96'>may</span>
+      <span class='ocrx_word' id='word_1_607' title='bbox 623 2556 797 2584; x_wconf 96'>OUTPUTS</span>
+      <span class='ocrx_word' id='word_1_608' title='bbox 808 2565 871 2590; x_wconf 96'>may</span>
      <span class='ocrx_word' id='word_1_609' title='bbox 881 2557 915 2584; x_wconf 96'>be</span>
      <span class='ocrx_word' id='word_1_610' title='bbox 925 2557 1119 2590; x_wconf 96'>programmed</span>
      <span class='ocrx_word' id='word_1_611' title='bbox 1129 2561 1158 2584; x_wconf 96'>to</span>
@@ -904,14 +904,14 @@
      <span class='ocrx_word' id='word_1_625' title='bbox 875 2610 907 2629; x_wconf 96'>or</span>
      <span class='ocrx_word' id='word_1_626' title='bbox 918 2602 989 2629; x_wconf 96'>Linn</span>
      <span class='ocrx_word' id='word_1_627' title='bbox 1000 2603 1069 2629; x_wconf 95'>9000</span>
-      <span class='ocrx_word' id='word_1_628' title='bbox 1080 2610 1129 2635; x_wconf 96'>sync</span>
-      <span class='ocrx_word' id='word_1_629' title='bbox 1131 2607 1226 2630; x_wconf 96'>tone.</span>
+      <span class='ocrx_word' id='word_1_628' title='bbox 1080 2610 1145 2635; x_wconf 96'>sync</span>
+      <span class='ocrx_word' id='word_1_629' title='bbox 1155 2607 1226 2630; x_wconf 96'>tone.</span>
     </span>
    </p>
   </div>
   <div class='ocr_carea' id='block_1_27' title="bbox 347 2648 2100 2727">
    <p class='ocr_par' id='par_1_35' lang='eng' title="bbox 347 2648 2100 2727">
-     <span class='ocr_line' id='line_1_72' title="bbox 347 2648 1664 2682; baseline 0.001 -7; x_size 33; x_descenders 6; x_ascenders 8">
+     <span class='ocr_header' id='line_1_72' title="bbox 347 2648 1664 2682; baseline 0.001 -7; x_size 33; x_descenders 6; x_ascenders 8">
      <span class='ocrx_word' id='word_1_630' title='bbox 347 2654 360 2667; x_wconf 45'>©</span>
      <span class='ocrx_word' id='word_1_631' title='bbox 372 2648 483 2675; x_wconf 95'>Utilizes</span>
      <span class='ocrx_word' id='word_1_632' title='bbox 493 2648 564 2680; x_wconf 96'>ultra</span>
@@ -927,17 +927,17 @@
      <span class='ocrx_word' id='word_1_642' title='bbox 1414 2649 1502 2676; x_wconf 96'>FAST</span>
      <span class='ocrx_word' id='word_1_643' title='bbox 1512 2648 1664 2682; x_wconf 96'>operation.</span>
     </span>
-     <span class='ocr_line' id='line_1_73' title="bbox 347 2694 2100 2727; baseline 0.001 -7; x_size 33; x_descenders 6; x_ascenders 8">
+     <span class='ocr_header' id='line_1_73' title="bbox 347 2694 2100 2727; baseline 0.001 -7; x_size 33; x_descenders 6; x_ascenders 8">
      <span class='ocrx_word' id='word_1_644' title='bbox 347 2699 361 2713; x_wconf 31'>*</span>
-      <span class='ocrx_word' id='word_1_645' title='bbox 372 2694 476 2720; x_wconf 96'>TEMPO</span>
-      <span class='ocrx_word' id='word_1_646' title='bbox 478 2694 562 2721; x_wconf 96'>may</span>
-      <span class='ocrx_word' id='word_1_647' title='bbox 561 2694 606 2727; x_wconf 95'>be</span>
-      <span class='ocrx_word' id='word_1_648' title='bbox 608 2694 764 2727; x_wconf 95'>specified</span>
+      <span class='ocrx_word' id='word_1_645' title='bbox 372 2694 504 2721; x_wconf 96'>TEMPO</span>
+      <span class='ocrx_word' id='word_1_646' title='bbox 515 2702 578 2727; x_wconf 96'>may</span>
+      <span class='ocrx_word' id='word_1_647' title='bbox 589 2694 623 2721; x_wconf 95'>be</span>
+      <span class='ocrx_word' id='word_1_648' title='bbox 633 2694 764 2727; x_wconf 95'>specified</span>
      <span class='ocrx_word' id='word_1_649' title='bbox 774 2694 802 2721; x_wconf 93'>in</span>
      <span class='ocrx_word' id='word_1_650' title='bbox 814 2695 1172 2722; x_wconf 91'>BEATS-PER-MINUTE</span>
      <span class='ocrx_word' id='word_1_651' title='bbox 1183 2703 1215 2722; x_wconf 93'>or</span>
-      <span class='ocrx_word' id='word_1_652' title='bbox 1225 2695 1547 2722; x_wconf 91'>FRAMES-PER-BEAT</span>
-      <span class='ocrx_word' id='word_1_653' title='bbox 1543 2695 1605 2721; x_wconf 96'>at</span>
+      <span class='ocrx_word' id='word_1_652' title='bbox 1225 2695 1567 2722; x_wconf 91'>FRAMES-PER-BEAT</span>
+      <span class='ocrx_word' id='word_1_653' title='bbox 1577 2698 1605 2721; x_wconf 96'>at</span>
      <span class='ocrx_word' id='word_1_654' title='bbox 1616 2695 1659 2726; x_wconf 96'>24,</span>
      <span class='ocrx_word' id='word_1_655' title='bbox 1672 2695 1716 2726; x_wconf 96'>25,</span>
      <span class='ocrx_word' id='word_1_656' title='bbox 1728 2702 1760 2721; x_wconf 96'>or</span>
@@ -959,11 +959,11 @@
   </div>
   <div class='ocr_carea' id='block_1_29' title="bbox 347 2777 2174 2811">
    <p class='ocr_par' id='par_1_37' lang='eng' title="bbox 347 2777 2174 2811">
-     <span class='ocr_line' id='line_1_75' title="bbox 347 2777 2174 2811; baseline 0.001 -8; x_size 33; x_descenders 5; x_ascenders 9">
+     <span class='ocr_header' id='line_1_75' title="bbox 347 2777 2174 2811; baseline 0.001 -8; x_size 33; x_descenders 5; x_ascenders 9">
      <span class='ocrx_word' id='word_1_664' title='bbox 347 2782 360 2796; x_wconf 81'>¢</span>
-      <span class='ocrx_word' id='word_1_665' title='bbox 372 2777 476 2803; x_wconf 94'>TEMPO</span>
-      <span class='ocrx_word' id='word_1_666' title='bbox 478 2777 562 2804; x_wconf 96'>may</span>
-      <span class='ocrx_word' id='word_1_667' title='bbox 561 2777 622 2810; x_wconf 96'>be</span>
+      <span class='ocrx_word' id='word_1_665' title='bbox 372 2777 504 2804; x_wconf 94'>TEMPO</span>
+      <span class='ocrx_word' id='word_1_666' title='bbox 515 2785 578 2810; x_wconf 96'>may</span>
+      <span class='ocrx_word' id='word_1_667' title='bbox 588 2777 622 2804; x_wconf 96'>be</span>
      <span class='ocrx_word' id='word_1_668' title='bbox 633 2778 741 2804; x_wconf 95'>entered</span>
      <span class='ocrx_word' id='word_1_669' title='bbox 751 2777 934 2811; x_wconf 96'>numerically,</span>
      <span class='ocrx_word' id='word_1_670' title='bbox 946 2777 1101 2811; x_wconf 95'>adjustable</span>
@@ -987,36 +987,36 @@
      <span class='ocrx_word' id='word_1_682' title='bbox 372 2822 410 2841; x_wconf 96'>on</span>
      <span class='ocrx_word' id='word_1_683' title='bbox 420 2815 466 2842; x_wconf 95'>the</span>
      <span class='ocrx_word' id='word_1_684' title='bbox 476 2815 545 2841; x_wconf 95'>TAP</span>
-      <span class='ocrx_word' id='word_1_685' title='bbox 556 2816 660 2842; x_wconf 95'>TEMPO</span>
-      <span class='ocrx_word' id='word_1_686' title='bbox 662 2815 808 2842; x_wconf 96'>button.</span>
+      <span class='ocrx_word' id='word_1_685' title='bbox 556 2815 689 2842; x_wconf 95'>TEMPO</span>
+      <span class='ocrx_word' id='word_1_686' title='bbox 699 2815 808 2842; x_wconf 96'>button.</span>
     </span>
    </p>
   </div>
   <div class='ocr_carea' id='block_1_31' title="bbox 347 2861 1792 2940">
    <p class='ocr_par' id='par_1_39' lang='eng' title="bbox 347 2861 1792 2940">
-     <span class='ocr_line' id='line_1_77' title="bbox 347 2861 1792 2895; baseline 0.001 -8; x_size 33; x_descenders 6; x_ascenders 8">
+     <span class='ocr_header' id='line_1_77' title="bbox 347 2861 1792 2895; baseline 0.001 -8; x_size 33; x_descenders 6; x_ascenders 8">
      <span class='ocrx_word' id='word_1_687' title='bbox 347 2866 360 2880; x_wconf 43'>¢</span>
      <span class='ocrx_word' id='word_1_688' title='bbox 372 2861 504 2887; x_wconf 96'>TEMPO</span>
-      <span class='ocrx_word' id='word_1_689' title='bbox 515 2861 677 2888; x_wconf 96'>CHANGES</span>
-      <span class='ocrx_word' id='word_1_690' title='bbox 679 2861 771 2894; x_wconf 96'>may</span>
+      <span class='ocrx_word' id='word_1_689' title='bbox 515 2861 696 2888; x_wconf 96'>CHANGES</span>
+      <span class='ocrx_word' id='word_1_690' title='bbox 707 2869 771 2894; x_wconf 96'>may</span>
      <span class='ocrx_word' id='word_1_691' title='bbox 781 2861 815 2888; x_wconf 96'>be</span>
-      <span class='ocrx_word' id='word_1_692' title='bbox 825 2869 1000 2894; x_wconf 96'>programmed</span>
-      <span class='ocrx_word' id='word_1_693' title='bbox 1001 2861 1087 2888; x_wconf 96'>into</span>
+      <span class='ocrx_word' id='word_1_692' title='bbox 825 2861 1019 2894; x_wconf 96'>programmed</span>
+      <span class='ocrx_word' id='word_1_693' title='bbox 1030 2861 1087 2888; x_wconf 96'>into</span>
      <span class='ocrx_word' id='word_1_694' title='bbox 1099 2869 1115 2888; x_wconf 95'>a</span>
      <span class='ocrx_word' id='word_1_695' title='bbox 1126 2870 1268 2895; x_wconf 96'>sequence,</span>
      <span class='ocrx_word' id='word_1_696' title='bbox 1280 2861 1344 2888; x_wconf 96'>with</span>
-      <span class='ocrx_word' id='word_1_697' title='bbox 1356 2866 1448 2888; x_wconf 95'>smooth</span>
-      <span class='ocrx_word' id='word_1_698' title='bbox 1450 2861 1635 2888; x_wconf 96'>transitions</span>
+      <span class='ocrx_word' id='word_1_697' title='bbox 1356 2862 1467 2888; x_wconf 95'>smooth</span>
+      <span class='ocrx_word' id='word_1_698' title='bbox 1478 2861 1635 2888; x_wconf 96'>transitions</span>
      <span class='ocrx_word' id='word_1_699' title='bbox 1646 2861 1670 2887; x_wconf 96'>if</span>
      <span class='ocrx_word' id='word_1_700' title='bbox 1679 2861 1792 2888; x_wconf 87'>desired.</span>
     </span>
-     <span class='ocr_line' id='line_1_78' title="bbox 347 2906 1507 2940; baseline 0.002 -8; x_size 33; x_descenders 7; x_ascenders 8">
+     <span class='ocr_header' id='line_1_78' title="bbox 347 2906 1507 2940; baseline 0.002 -8; x_size 33; x_descenders 7; x_ascenders 8">
      <span class='ocrx_word' id='word_1_701' title='bbox 347 2911 360 2925; x_wconf 69'>¢</span>
      <span class='ocrx_word' id='word_1_702' title='bbox 371 2906 434 2938; x_wconf 96'>Any</span>
      <span class='ocrx_word' id='word_1_703' title='bbox 444 2906 539 2932; x_wconf 96'>TIME</span>
-      <span class='ocrx_word' id='word_1_704' title='bbox 550 2906 739 2933; x_wconf 96'>SIGNATURE</span>
-      <span class='ocrx_word' id='word_1_705' title='bbox 740 2907 820 2933; x_wconf 96'>may</span>
-      <span class='ocrx_word' id='word_1_706' title='bbox 819 2907 880 2939; x_wconf 96'>be</span>
+      <span class='ocrx_word' id='word_1_704' title='bbox 550 2906 763 2933; x_wconf 96'>SIGNATURE</span>
+      <span class='ocrx_word' id='word_1_705' title='bbox 773 2915 836 2939; x_wconf 96'>may</span>
+      <span class='ocrx_word' id='word_1_706' title='bbox 846 2907 880 2933; x_wconf 96'>be</span>
      <span class='ocrx_word' id='word_1_707' title='bbox 891 2907 968 2938; x_wconf 96'>used,</span>
      <span class='ocrx_word' id='word_1_708' title='bbox 980 2907 1036 2934; x_wconf 96'>and</span>
      <span class='ocrx_word' id='word_1_709' title='bbox 1046 2915 1109 2940; x_wconf 96'>may</span>
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.0.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.0.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -1 +1 @@
-Tesseract Open Source OCR Engine v4.0.0 with Leptonica
+Tesseract Open Source OCR Engine v4.1.1 with Leptonica
@@ -103,7 +103,7 @@ ERASE, REPEAT, PLAY/STOP, or LOCATE.

 © Will sync to standard LinnDrum or Linn 9000 sync tone.

-© Utilizes ultra high-speed, 8 MHz 80186 16 bit computer internally for FAST operation.
+® Utilizes ultra high-speed, 8 MHz 80186 16 bit computer internally for FAST operation.
 * TEMPO may be specified in BEATS-PER-MINUTE or FRAMES-PER-BEAT at 24, 25, or 30 frames per second,

 (even drop frame!)
@@ -115,9 +115,9 @@ on the TAP TEMPO button.
 ¢ TEMPO CHANGES may be programmed into a sequence, with smooth transitions if desired.
 ¢ Any TIME SIGNATURE may be used, and may be changed within a song.

-linn
-Linn Electronics, Inc.
+nn

+Linn Electronics, Inc.
 18720 Oxnard Street, Tarzana, CA 91356
 (818) 708-8131 TELEX #298949 LINN UR

--- a/Show More
+++ b/Show More