65 lines
1.7 KiB
Python
65 lines
1.7 KiB
Python
# SPDX-FileCopyrightText: 2022 James R. Barlow
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# SPDX-License-Identifier: MPL-2.0
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"""Interface to pngquant executable."""
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from __future__ import annotations
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from contextlib import contextmanager
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from io import BytesIO
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from pathlib import Path
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from subprocess import PIPE
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from packaging.version import Version
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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() -> Version:
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return Version(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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def quantize_mp(args):
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return quantize(*args)
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