v11.5.0 release notes

Might fix issue #709, Apple silicon support.

.coveragerc

@@ -1,24 +0,0 @@
-[paths]
-source =
-	src
-	*/site-packages
-
-[run]
-branch = true
-parallel = true
-concurrency =
-	thread
-	multiprocessing
-source =
-	src/ocrmypdf
-
-[report]
-exclude_lines =
-	pragma: no cover
-	def __repr__
-	raise AssertionError
-	raise NotImplementedError
-	if 0:
-	if False:
-	if __name__ == .__main__.:
-	if TYPE_CHECKING:

docs/api.rst

@@ -56,6 +56,11 @@ 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.
 
+``ocrmypdf.ocr()`` will take a threading lock to prevent multiple runs of itself
+in the same Python interpreter process. This is not thread-safe, because of how
+OCRmyPDF's plugins and Python's library import system work. If you need to parallelize
+OCRmyPDF, use processes.
+
 .. warning::
 
     On Windows and macOS, the script that calls ``ocrmypdf.ocr()`` must be

docs/release_notes.rst

@@ -12,6 +12,36 @@ may be unreliable. Use the API to depend on precise behavior.
 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.
 
+v11.5.0
+=======
+
+-  Fixed an issue where the output page size might differ by a fractional amount
+   due to rounding, when ``--force-ocr`` was used and the page contained objects
+   with multiple resolutions.
+-  When determining the resolution at which to rasterize a page, we now consider
+   printed text on the page as requiring a higher resolution. This fixes issues
+   with certain pages being rendered with unacceptably low resolution text, but
+   may increase output file sizes in some workflows where low resolution text
+   is acceptable.
+-  Added a workaround to fix an exception that occurs when trying to
+   ``import ocrmypdf.leptonica`` on Apple ARM silicon (or potentially, other
+   platforms that do not permit write+executable memory).
+
+v11.4.5
+=======
+
+-  Fixed an issue where files may not be closed when the API is used.
+-  Improved ``setup.cfg`` with better settings for test coverage.
+
+v11.4.4
+=======
+
+-  Fixed ``AttributeError: 'NoneType' object has no attribute 'userunit'``, issue #700,
+   related to OCRmyPDF not properly forwarded an error message from pdfminer.six.
+-  Adjusted typing of some arguments.
+-  ``ocrmypdf.ocr`` now takes a ``threading.Lock`` for reasons outlined in the
+   documentation.
+
 v11.4.3
 =======
 

setup.cfg

@@ -15,6 +15,8 @@ filterwarnings =
 	ignore:.*XMLParser.*:DeprecationWarning
 markers =
 	slow
+addopts =
+	-n auto
 
 [isort]
 multi_line_output=3
@@ -27,3 +29,30 @@ known_third_party = PIL,_cffi_backend,cffi,flask,img2pdf,pdfminer,pikepdf,pkg_re
 
 [metadata]
 license_file = LICENSE
+
+[coverage:paths]
+source =
+	src/
+
+[coverage:run]
+branch = true
+parallel = true
+concurrency = multiprocessing
+source =
+	src/ocrmypdf
+
+[coverage:report]
+# Regexes for lines to exclude from consideration
+exclude_lines =
+    # Have to re-enable the standard pragma
+    pragma: no cover
+
+    # Don't complain if tests don't hit defensive assertion code:
+    raise AssertionError
+    raise NotImplementedError
+
+    # Don't complain if non-runnable code isn't run:
+    if 0:
+	if False:
+    if __name__ == .__main__.:
+	if TYPE_CHECKING:

src/ocrmypdf/_concurrent.py

@@ -109,15 +109,11 @@ def exec_progress_pool(
         )
         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
+            for result in results:
+                if task_finished:
+                    task_finished(result, pbar)
+                else:
+                    pbar.update()
         except KeyboardInterrupt:
             # Terminate pool so we exit instantly
             pool.terminate()

src/ocrmypdf/_exec/ghostscript.py

@@ -15,7 +15,7 @@ from os import fspath
 from pathlib import Path
 from shutil import which
 from subprocess import PIPE, CalledProcessError
-from typing import Optional, cast
+from typing import Optional
 
 from PIL import Image
 
@@ -56,16 +56,14 @@ def version():
 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
+    Prior to 9.23, Ghostscript decoded and re-encoded JPEGs internally. In 9.23
     it gained the ability to keep JPEGs unmodified. However, the 9.23
     implementation was buggy and would deletes the last two bytes of images in
     some cases, as reported here.
     https://bugs.ghostscript.com/show_bug.cgi?id=699216
 
     The issue was fixed for 9.24, hence that is the first version we consider
-    the feature available. (However, we don't use 9.24 at all, so the first
-    version that allows JPEG passthrough is 9.25.
-
+    the feature available. (Ghostscript 9.24 has its own problems is blacklisted.)
     """
     return version() >= '9.24'
 

src/ocrmypdf/_exec/tesseract.py

@@ -14,7 +14,7 @@ from collections import namedtuple
 from os import fspath
 from pathlib import Path
 from subprocess import PIPE, STDOUT, CalledProcessError, TimeoutExpired
-from typing import List
+from typing import List, Optional
 
 from PIL import Image
 
@@ -118,7 +118,7 @@ def get_languages():
     return set(lang.strip() for lang in rest)
 
 
-def tess_base_args(langs: List[str], engine_mode: int) -> List[str]:
+def tess_base_args(langs: List[str], engine_mode: Optional[int]) -> List[str]:
     args = ['tesseract']
     if langs:
         args.extend(['-l', '+'.join(langs)])
@@ -127,7 +127,7 @@ def tess_base_args(langs: List[str], engine_mode: int) -> List[str]:
     return args
 
 
-def get_orientation(input_file: Path, engine_mode: int, timeout: float):
+def get_orientation(input_file: Path, engine_mode: Optional[int], timeout: float):
     args_tesseract = tess_base_args(['osd'], engine_mode) + [
         '--psm',
         '0',

src/ocrmypdf/_pipeline.py

@@ -206,17 +206,21 @@ def validate_pdfinfo_options(context: PdfContext):
     context.plugin_manager.hook.validate(pdfinfo=pdfinfo, options=options)
 
 
+def _vector_page_dpi(pageinfo):
+    return VECTOR_PAGE_DPI if pageinfo.has_vector or pageinfo.has_text else 0.0
+
+
 def get_page_dpi(pageinfo, options):
     "Get the DPI when nonsquare DPI is tolerable"
     xres = max(
         pageinfo.dpi.x or VECTOR_PAGE_DPI,
         options.oversample or 0.0,
-        VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
+        _vector_page_dpi(pageinfo),
     )
     yres = max(
         pageinfo.dpi.y or VECTOR_PAGE_DPI,
         options.oversample or 0,
-        VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
+        _vector_page_dpi(pageinfo),
     )
     return Resolution(float(xres), float(yres))
 
@@ -230,7 +234,7 @@ def get_page_square_dpi(pageinfo, options) -> Resolution:
         max(
             (xres * userunit) or VECTOR_PAGE_DPI,
             (yres * userunit) or VECTOR_PAGE_DPI,
-            VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
+            _vector_page_dpi(pageinfo),
             options.oversample or 0.0,
         )
     )
@@ -243,7 +247,7 @@ def get_canvas_square_dpi(pageinfo, options) -> Resolution:
         max(
             (pageinfo.dpi.x) or VECTOR_PAGE_DPI,
             (pageinfo.dpi.y) or VECTOR_PAGE_DPI,
-            VECTOR_PAGE_DPI if pageinfo.has_vector else 0.0,
+            _vector_page_dpi(pageinfo),
             options.oversample or 0.0,
         )
     )
@@ -588,12 +592,17 @@ def create_pdf_page_from_image(image: Path, page_context: PageContext):
     # except that the hocr renderer does not understand non-square DPI. The
     # 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)
+
+    pageinfo = page_context.pageinfo
+    pagesize = 72.0 * float(pageinfo.width_inches), 72.0 * float(pageinfo.height_inches)
+    if pageinfo.rotation % 180 == 90:
+        pagesize = pagesize[1], pagesize[0]
 
     # This create a single page PDF
     with open(image, 'rb') as imfile, open(output_file, 'wb') as pdf:
         log.debug('convert')
+
+        layout_fun = img2pdf.get_layout_fun(pagesize)
         img2pdf.convert(
             imfile, with_pdfrw=False, layout_fun=layout_fun, outputstream=pdf
         )

src/ocrmypdf/_sync.py

@@ -302,7 +302,7 @@ def exec_concurrent(context: PdfContext):
     copy_final(pdf, options.output_file, context)
 
 
-def configure_debug_logging(log_filename, prefix: str = ''):
+def configure_debug_logging(log_filename: Path, prefix: str = ''):
     """
     Create a debug log file at a specified location.
 
@@ -338,7 +338,11 @@ def run_pipeline(options, *, plugin_manager, api=False):
         and not api
     ):
         # Debug log for command line interface only with verbose output
-        debug_log_handler = configure_debug_logging(Path(work_folder) / "debug.log")
+        # See https://github.com/pytest-dev/pytest/issues/5502 for why we skip this
+        # when pytest is running
+        debug_log_handler = configure_debug_logging(
+            Path(work_folder) / "debug.log"
+        )  # pragma: no cover
 
     pikepdf_enable_mmap()
 

src/ocrmypdf/api.py

@@ -8,6 +8,7 @@
 import logging
 import os
 import sys
+import threading
 from enum import IntEnum
 from io import IOBase
 from pathlib import Path
@@ -30,6 +31,8 @@ except ModuleNotFoundError:
 StrPath = Union[os.PathLike, AnyStr]
 PathOrIO = Union[BinaryIO, StrPath]
 
+_api_lock = threading.Lock()
+
 
 class Verbosity(IntEnum):
     """Verbosity level for configure_logging."""
@@ -306,12 +309,18 @@ def ocr(  # pylint: disable=unused-argument
 
     parser = get_parser()
     create_options_kwargs['parser'] = parser
-    plugin_manager = get_plugin_manager(plugins)
-    plugin_manager.hook.add_options(parser=parser)  # pylint: disable=no-member
 
-    if 'verbose' in kwargs:
-        warn("ocrmypdf.ocr(verbose=) is ignored. Use ocrmypdf.configure_logging().")
+    with _api_lock:
+        # We can't allow multiple ocrmypdf.ocr() threads to run in parallel, because
+        # they might install different plugins, and generally speaking we have areas
+        # of code that use global state.
 
-    options = create_options(**create_options_kwargs)
-    check_options(options, plugin_manager)
-    return run_pipeline(options=options, plugin_manager=plugin_manager, api=True)
+        plugin_manager = get_plugin_manager(plugins)
+        plugin_manager.hook.add_options(parser=parser)  # pylint: disable=no-member
+
+        if 'verbose' in kwargs:
+            warn("ocrmypdf.ocr(verbose=) is ignored. Use ocrmypdf.configure_logging().")
+
+        options = create_options(**create_options_kwargs)
+        check_options(options, plugin_manager)
+        return run_pipeline(options=options, plugin_manager=plugin_manager, api=True)

src/ocrmypdf/leptonica.py

@@ -13,6 +13,7 @@
 import argparse
 import logging
 import os
+import platform
 import sys
 import threading
 import warnings
@@ -170,20 +171,6 @@ 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()
@@ -213,9 +200,25 @@ class _LeptonicaErrorTrap_Queue:
 
 
 try:
+
+    @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
+
     lept.leptSetStderrHandler(_stderr_handler)
-except ffi.error:
+except (ffi.error, MemoryError):
     # Pre-1.79 Leptonica does not have leptSetStderrHandler
+    # And some platforms, notably Apple ARM 64, do not allow the write+execute
+    # memory needed to set up the callback function.
     _LeptonicaErrorTrap = _LeptonicaErrorTrap_Redirect
 else:
     # 1.79 have this new symbol

src/ocrmypdf/optimize.py

@@ -498,7 +498,7 @@ def transcode_pngs(
 
 
 @deprecated
-def rewrite_png_as_g4(pike: Pdf, im_obj: Object, compdata) -> None:
+def rewrite_png_as_g4(pike: Pdf, im_obj: Object, compdata) -> None:  # pragma: no cover
     im_obj.BitsPerComponent = 1
     im_obj.Width = compdata.w
     im_obj.Height = compdata.h
@@ -519,7 +519,7 @@ def rewrite_png_as_g4(pike: Pdf, im_obj: Object, compdata) -> None:
 
 
 @deprecated
-def rewrite_png(pike: Pdf, im_obj: Object, compdata) -> None:
+def rewrite_png(pike: Pdf, im_obj: Object, compdata) -> None:  # pragma: no cover
     # 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

src/ocrmypdf/pdfinfo/info.py

@@ -22,7 +22,7 @@ import pikepdf
 from pikepdf import Object, Pdf, PdfMatrix
 
 from ocrmypdf._concurrent import exec_progress_pool
-from ocrmypdf.exceptions import EncryptedPdfError
+from ocrmypdf.exceptions import EncryptedPdfError, InputFileError
 from ocrmypdf.helpers import Resolution, available_cpu_count, pikepdf_enable_mmap
 from ocrmypdf.pdfinfo.layout import get_page_analysis, get_text_boxes
 
@@ -598,6 +598,8 @@ def _pdf_pageinfo_concurrent(
 
     def update_pageinfo(result, pbar):
         page = result
+        if not page:
+            raise InputFileError("Could read a page in the PDF")
         pages[page.pageno] = page
         pbar.update()
 

src/ocrmypdf/pdfinfo/layout.py

@@ -21,7 +21,7 @@ from pdfminer.pdffont import PDFSimpleFont, PDFUnicodeNotDefined
 from pdfminer.pdfpage import PDFPage
 from pdfminer.utils import bbox2str, matrix2str
 
-from ocrmypdf.exceptions import EncryptedPdfError
+from ocrmypdf.exceptions import EncryptedPdfError, InputFileError
 
 STRIP_NAME = re.compile(r'[0-9]+')
 
@@ -236,8 +236,13 @@ def get_page_analysis(infile, pageno, pscript5_mode):
 
     try:
         with Path(infile).open('rb') as f:
-            page = PDFPage.get_pages(f, pagenos=[pageno], maxpages=0)
-            interp.process_page(next(page))
+            page_iter = PDFPage.get_pages(f, pagenos=[pageno], maxpages=0)
+            page = next(page_iter, None)
+            if page is None:
+                raise InputFileError(
+                    f"pdfminer could not process page {pageno} (counting from 0)."
+                )
+            interp.process_page(page)
     except PDFTextExtractionNotAllowed as e:
         raise EncryptedPdfError() from e
     finally:

src/ocrmypdf/subprocess/__init__.py

@@ -77,20 +77,19 @@ def run_polling_stderr(args, *, callback, check=False, env=None, **kwargs):
     args, env, process_log, text = _fix_process_args(args, env, kwargs)
     assert text, "Must use text=True"
 
-    proc = Popen(args, env=env, **kwargs)
+    with Popen(args, env=env, **kwargs) as proc:
+        lines = []
+        while proc.poll() is None:
+            for msg in iter(proc.stderr.readline, ''):
+                if process_log.isEnabledFor(logging.DEBUG):
+                    process_log.debug(msg.strip())
+                callback(msg)
+                lines.append(msg)
+        stderr = ''.join(lines)
 
-    lines = []
-    while proc.poll() is None:
-        for msg in iter(proc.stderr.readline, ''):
-            if process_log.isEnabledFor(logging.DEBUG):
-                process_log.debug(msg.strip())
-            callback(msg)
-            lines.append(msg)
-    stderr = ''.join(lines)
-
-    if check and proc.returncode != 0:
-        raise CalledProcessError(proc.returncode, args, output=None, stderr=stderr)
-    return CompletedProcess(args, proc.returncode, None, stderr=stderr)
+        if check and proc.returncode != 0:
+            raise CalledProcessError(proc.returncode, args, output=None, stderr=stderr)
+        return CompletedProcess(args, proc.returncode, None, stderr=stderr)
 
 
 def _fix_process_args(args, env, kwargs):

tests/conftest.py

@@ -137,16 +137,7 @@ def run_ocrmypdf(input_file, output_file, *args, text=True):
         + [str(input_file), str(output_file)]
     )
 
-    # Tell subprocess where to find coverage.py configuration
-    # This has no unless except when coverage is running
-    # Details: https://coverage.readthedocs.io/en/coverage-5.0/subprocess.html
-    coverage_rc = Path(__file__).parent.parent / '.coveragerc'
     env = os.environ.copy()
-    if coverage_rc.exists():
-        env['COVERAGE_PROCESS_START'] = os.fspath(coverage_rc)
-    elif not running_in_docker():
-        assert False, "could not find .coveragerc"
-
     p = run(
         p_args,
         stdout=PIPE,

tests/test_logging.py

@@ -0,0 +1,21 @@
+# © 2021 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 pytest
+
+from ocrmypdf._sync import configure_debug_logging
+
+
+def test_debug_logging(tmp_path):
+    # Just exercise the debug logger but don't validate it
+    # See https://github.com/pytest-dev/pytest/issues/5502 for pytest logging quirks
+    prefix = 'test_debug_logging'
+    log = logging.getLogger(prefix)
+    handler = configure_debug_logging(tmp_path / 'test.log', prefix)
+    log.info("test message")
+    log.removeHandler(handler)

tests/test_pdfinfo.py

@@ -4,28 +4,31 @@
 # 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 pickle
+from io import BytesIO
 from math import isclose
 
 import img2pdf
 import pikepdf
 import pytest
 from PIL import Image
+from reportlab.lib.units import inch
 from reportlab.pdfgen.canvas import Canvas
 
 from ocrmypdf import pdfinfo
+from ocrmypdf.exceptions import InputFileError
 from ocrmypdf.pdfinfo import Colorspace, Encoding
+from ocrmypdf.pdfinfo.layout import PDFPage
 
 # pylint: disable=protected-access
 
 
 def test_single_page_text(outdir):
     filename = outdir / 'text.pdf'
-    pdf = Canvas(str(filename), pagesize=(8 * 72, 6 * 72))
+    pdf = Canvas(str(filename), pagesize=(8 * inch, 6 * inch))
     text = pdf.beginText()
     text.setFont('Helvetica', 12)
-    text.setTextOrigin(1 * 72, 3 * 72)
+    text.setTextOrigin(1 * inch, 3 * inch)
     text.textLine(
         "Methink'st thou art a general offence and every" " man should beat thee."
     )
@@ -42,25 +45,32 @@ def test_single_page_text(outdir):
     assert len(page.images) == 0
 
 
-def test_single_page_image(outdir):
-    filename = outdir / 'image-mono.pdf'
-
-    im_tmp = outdir / 'tmp.png'
+@pytest.fixture(scope='session')
+def eight_by_eight():
     im = Image.new('1', (8, 8), 0)
     for n in range(8):
         im.putpixel((n, n), 1)
-    im.save(str(im_tmp), format='PNG')
+    return im
+
+
+def test_single_page_image(eight_by_eight, outpdf):
+    im = eight_by_eight
+    bio = BytesIO()
+    im.save(bio, format='PNG')
+    bio.seek(0)
 
     imgsize = ((img2pdf.ImgSize.dpi, 8), (img2pdf.ImgSize.dpi, 8))
     layout_fun = img2pdf.get_layout_fun(None, imgsize, None, None, None)
 
-    im_bytes = im_tmp.read_bytes()
-    pdf_bytes = img2pdf.convert(
-        im_bytes, producer="img2pdf", with_pdfrw=False, layout_fun=layout_fun
-    )
-    filename.write_bytes(pdf_bytes)
-
-    info = pdfinfo.PdfInfo(filename)
+    with outpdf.open('wb') as f:
+        img2pdf.convert(
+            bio,
+            producer="img2pdf",
+            with_pdfrw=False,
+            layout_fun=layout_fun,
+            outputstream=f,
+        )
+    info = pdfinfo.PdfInfo(outpdf)
 
     assert len(info) == 1
     page = info[0]
@@ -77,16 +87,12 @@ def test_single_page_image(outdir):
     assert isclose(pdfimage.dpi.y, 8)
 
 
-def test_single_page_inline_image(outdir):
+def test_single_page_inline_image(eight_by_eight, outdir):
     filename = outdir / 'image-mono-inline.pdf'
     pdf = Canvas(str(filename), pagesize=(8 * 72, 6 * 72))
 
-    im = Image.new('1', (8, 8), 0)
-    for n in range(8):
-        im.putpixel((n, n), 1)
-
     # Draw image in a 72x72 pt or 1"x1" area
-    pdf.drawInlineImage(im, 0, 0, width=72, height=72)
+    pdf.drawInlineImage(eight_by_eight, 0, 0, width=72, height=72)
     pdf.showPage()
     pdf.save()
 
@@ -179,3 +185,18 @@ def test_stack_abuse():
     with pytest.warns(None):
         with pytest.raises(RuntimeError):
             pdfinfo.info._interpret_contents(stream)
+
+
+def test_pages_issue700(monkeypatch, resources):
+    def get_no_pages(*args, **kwargs):
+        return iter([])
+
+    monkeypatch.setattr(PDFPage, 'get_pages', get_no_pages)
+
+    with pytest.raises(InputFileError, match="pdfminer"):
+        pdfinfo.PdfInfo(
+            resources / 'cardinal.pdf',
+            detailed_analysis=True,
+            progbar=False,
+            max_workers=1,
+        )

tests/test_pipeline.py

@@ -0,0 +1,63 @@
+# © 2021 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 unittest.mock import Mock
+
+import pytest
+from PIL import Image
+from reportlab.lib.units import inch
+from reportlab.lib.utils import ImageReader
+from reportlab.pdfgen.canvas import Canvas
+
+from ocrmypdf import _pipeline, pdfinfo
+from ocrmypdf.helpers import Resolution
+
+
+@pytest.fixture(scope='session')
+def rgb_image():
+    im = Image.new('RGB', (8, 8))
+    im.putpixel((4, 4), (255, 0, 0))
+    im.putpixel((5, 5), (0, 255, 0))
+    im.putpixel((6, 6), (0, 0, 255))
+    return ImageReader(im)
+
+
+DUMMY_OVERSAMPLE_RESOLUTION = Resolution(42.0, 42.0)
+VECTOR_RESOLUTION = Resolution(_pipeline.VECTOR_PAGE_DPI, _pipeline.VECTOR_PAGE_DPI)
+
+
+@pytest.mark.parametrize(
+    'image, text, vector, result',
+    [
+        (False, False, False, VECTOR_RESOLUTION),
+        (False, True, False, VECTOR_RESOLUTION),
+        (True, False, False, DUMMY_OVERSAMPLE_RESOLUTION),
+        (True, True, False, VECTOR_RESOLUTION),
+        (False, False, True, VECTOR_RESOLUTION),
+        (False, True, True, VECTOR_RESOLUTION),
+        (True, False, True, VECTOR_RESOLUTION),
+        (True, True, True, VECTOR_RESOLUTION),
+    ],
+)
+def test_dpi_needed(image, text, vector, result, rgb_image, outdir):
+
+    c = Canvas(str(outdir / 'dpi.pdf'), pagesize=(5 * inch, 5 * inch))
+    if image:
+        c.drawImage(rgb_image, 1 * inch, 1 * inch, width=1 * inch, height=1 * inch)
+    if text:
+        c.drawString(1 * inch, 4 * inch, "Actual text")
+    if vector:
+        c.ellipse(3 * inch, 3 * inch, 4 * inch, 4 * inch)
+    c.showPage()
+    c.save()
+
+    mock = Mock()
+    mock.oversample = DUMMY_OVERSAMPLE_RESOLUTION[0]
+
+    pi = pdfinfo.PdfInfo(outdir / 'dpi.pdf')
+
+    assert _pipeline.get_canvas_square_dpi(pi[0], mock) == result
+    assert _pipeline.get_page_square_dpi(pi[0], mock) == result

tests/test_tesseract.py

@@ -45,7 +45,8 @@ def test_skip_pages_does_not_replicate(resources, basename, outdir):
         assert len(page.images) == 1, "skipped page was replicated"
 
     for n, info_out_n in enumerate(info):
-        assert info_out_n.width_inches == info_in[n].width_inches
+        assert info_out_n.width_inches == info_in[n].width_inches, "output resized"
+        assert info_out_n.height_inches == info_in[n].height_inches, "output resized"
 
 
 def test_content_preservation(resources, outpdf):