Move ocrmypdf to src/ocrmypdf
This commit is contained in:
James R. Barlow
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# © 2017 James R. Barlow: github.com/jbarlow83
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#
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# This file is part of OCRmyPDF.
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#
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# OCRmyPDF is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, either version 3 of the License, or
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# (at your option) any later version.
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#
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# OCRmyPDF is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with OCRmyPDF. If not, see <http://www.gnu.org/licenses/>.
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from tempfile import NamedTemporaryFile
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from subprocess import run, PIPE, STDOUT, CalledProcessError
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from shutil import copy
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from functools import lru_cache
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import re
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import sys
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from PIL import Image
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from . import get_version
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from ..exceptions import SubprocessOutputError, MissingDependencyError
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from ..helpers import fspath
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@lru_cache(maxsize=1)
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def version():
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return get_version('gs')
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def _gs_error_reported(stream):
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return re.search(r'error', stream, flags=re.IGNORECASE)
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def rasterize_pdf(input_file, output_file, xres, yres, raster_device, log,
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pageno=1, page_dpi=None):
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"""
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Rasterize one page of a PDF at resolution (xres, yres) in canvas units.
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The image is sized to match the integer pixels dimensions implied by
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(xres, yres) even if those numbers are noninteger. The image's DPI will
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be overridden with the values in page_dpi.
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:param input_file: pathlike
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:param output_file: pathlike
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:param xres: resolution at which to rasterize page
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:param yres:
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:param raster_device:
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:param log:
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:param pageno: page number to rasterize (beginning at page 1)
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:param page_dpi: resolution tuple (x, y) overriding output image DPI
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:return:
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"""
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res = xres, yres
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int_res = round(xres), round(yres)
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if not page_dpi:
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page_dpi = res
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with NamedTemporaryFile(delete=True) as tmp:
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args_gs = [
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'gs',
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'-dQUIET',
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'-dSAFER',
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'-dBATCH',
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'-dNOPAUSE',
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'-sDEVICE=%s' % raster_device,
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'-dFirstPage=%i' % pageno,
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'-dLastPage=%i' % pageno,
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'-r{0}x{1}'.format(str(int_res[0]), str(int_res[1])),
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'-o', tmp.name,
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fspath(input_file)
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]
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p = run(args_gs, stdout=PIPE, stderr=STDOUT,
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universal_newlines=True)
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if _gs_error_reported(p.stdout):
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log.error(p.stdout)
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else:
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log.debug(p.stdout)
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if p.returncode != 0:
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log.error('Ghostscript rasterizing failed')
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raise SubprocessOutputError()
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# Ghostscript only accepts integers for output resolution
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# if the resolution happens to be fractional, then the discrepancy
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# would change the size of the output page, especially if the DPI
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# is quite low. Resize the image to the expected size
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tmp.seek(0)
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with Image.open(tmp) as im:
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expected_size = round(im.size[0] / int_res[0] * res[0]), \
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round(im.size[1] / int_res[1] * res[1])
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if expected_size != im.size or page_dpi != (xres, yres):
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log.debug(
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"Ghostscript: resize output image {} -> {}".format(
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im.size, expected_size))
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im.resize(expected_size).save(
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fspath(output_file), dpi=page_dpi)
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else:
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copy(tmp.name, fspath(output_file))
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def generate_pdfa(pdf_pages, output_file, compression, log,
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threads=1, pdf_version='1.5', pdfa_part='2'):
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compression_args = []
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if compression == 'jpeg':
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compression_args = [
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"-dAutoFilterColorImages=false",
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"-dColorImageFilter=/DCTEncode",
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"-dAutoFilterGrayImages=false",
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"-dGrayImageFilter=/DCTEncode",
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]
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elif compression == 'lossless':
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compression_args = [
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"-dAutoFilterColorImages=false",
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"-dColorImageFilter=/FlateEncode",
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"-dAutoFilterGrayImages=false",
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"-dGrayImageFilter=/FlateEncode",
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]
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else:
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compression_args = [
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"-dAutoFilterColorImages=true",
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"-dAutoFilterGrayImages=true",
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]
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with NamedTemporaryFile(delete=True) as gs_pdf:
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args_gs = [
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"gs",
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"-dQUIET",
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"-dBATCH",
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"-dNOPAUSE",
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"-dCompatibilityLevel=" + str(pdf_version),
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"-dNumRenderingThreads=" + str(threads),
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"-sDEVICE=pdfwrite",
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"-dAutoRotatePages=/None",
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"-sColorConversionStrategy=/RGB",
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"-sProcessColorModel=DeviceRGB"
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] + compression_args + [
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"-dJPEGQ=95",
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"-dPDFA=" + pdfa_part,
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"-dPDFACompatibilityPolicy=1",
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"-sOutputFile=" + gs_pdf.name,
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]
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args_gs.extend(pdf_pages)
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p = run(args_gs, stdout=PIPE, stderr=STDOUT,
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universal_newlines=True)
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if _gs_error_reported(p.stdout):
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log.error(p.stdout)
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elif 'overprint mode not set' in p.stdout:
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# Unless someone is going to print PDF/A documents on a
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# magical sRGB printer I can't see the removal of overprinting
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# being a problem....
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log.debug(
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"Ghostscript had to remove PDF 'overprinting' from the "
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"input file to complete PDF/A conversion. "
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)
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else:
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log.debug(p.stdout)
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if p.returncode == 0:
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# Ghostscript does not change return code when it fails to create
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# PDF/A - check PDF/A status elsewhere
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copy(gs_pdf.name, output_file)
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else:
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log.error('Ghostscript PDF/A rendering failed')
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raise SubprocessOutputError()
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