64 lines
1.7 KiB
Python
64 lines
1.7 KiB
Python
# © 2018 James R. Barlow: github.com/jbarlow83
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, You can obtain one at http://mozilla.org/MPL/2.0/.
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"""Interface to pngquant executable"""
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from contextlib import contextmanager
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from io import BytesIO
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from os import fspath
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from pathlib import Path
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from subprocess import PIPE
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from tempfile import NamedTemporaryFile
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from PIL import Image
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from ocrmypdf.exceptions import MissingDependencyError
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from ocrmypdf.subprocess import get_version, run
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def version():
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return get_version('pngquant', regex=r'(\d+(\.\d+)*).*')
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def available():
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try:
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version()
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except MissingDependencyError:
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return False
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return True
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@contextmanager
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def input_as_png(input_file: Path):
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if not input_file.name.endswith('.png'):
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with Image.open(input_file) as im:
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bio = BytesIO()
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im.save(bio, format='png')
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bio.seek(0)
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yield bio
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else:
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with open(input_file, 'rb') as f:
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yield f
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def quantize(input_file: Path, output_file: Path, quality_min: int, quality_max: int):
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with input_as_png(input_file) as input_stream:
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args = [
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'pngquant',
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'--force',
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'--skip-if-larger',
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'--quality',
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f'{quality_min}-{quality_max}',
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'--', # pngquant: stop processing arguments
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'-', # pngquant: stream input and output
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]
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result = run(args, stdin=input_stream, stdout=PIPE, stderr=PIPE, check=False)
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if result.returncode == 0:
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# input_file could be the same as output_file, so we defer the write
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output_file.write_bytes(result.stdout)
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