khodowany
46 lines
2.0 KiB
Python
46 lines
2.0 KiB
Python
from __future__ import annotations
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import hashlib
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import io
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import pathlib
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import re
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import PIL.Image
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import PIL.ImageChops
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import generator.engraving.types
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import generator.theme
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ENGINE_NAME = 'Vamp Python'
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PAGE_WIDTH = 976
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PAGE_HEIGHT = 484
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def check_content(data: bytes, name: str) -> None:
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with PIL.Image.open(io.BytesIO(data)) as image:
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if image.format != 'PNG' or image.size != (PAGE_WIDTH, PAGE_HEIGHT):
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raise generator.engraving.types.EngravingError(f'{name}: expected a {PAGE_WIDTH}x{PAGE_HEIGHT} PNG page')
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image.load()
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background = PIL.Image.new('RGB', image.size, generator.theme.rgb('background'))
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composited = background.convert('RGBA')
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composited.alpha_composite(image.convert('RGBA'))
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ink = PIL.ImageChops.difference(composited.convert('RGB'), background).convert('L').point(lambda x: 255 if x > 32 else 0)
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bounds = ink.getbbox()
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if not bounds:
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raise generator.engraving.types.EngravingError(f'{name}: engraver produced a blank page')
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if bounds[0] < 4 or bounds[1] < 4 or bounds[2] > PAGE_WIDTH - 4 or bounds[3] > PAGE_HEIGHT - 4:
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raise generator.engraving.types.EngravingError(f'{name}: notation reaches the page edge; refusing potentially clipped output')
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def check_page(path: pathlib.Path, validated_pages: set[str] | None = None, *, expected_sha256: str | None = None) -> str:
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# Trust content, never a filename or a caller-supplied checksum alone.
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if path.is_symlink() or not path.is_file():
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raise generator.engraving.types.EngravingError(f'{path.name}: expected a regular PNG file')
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data = path.read_bytes()
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digest = hashlib.sha256(data).hexdigest()
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if expected_sha256 is not None and (not isinstance(expected_sha256, str) or not re.fullmatch('[0-9a-f]{64}', expected_sha256) or digest != expected_sha256):
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raise generator.engraving.types.EngravingError(f'{path.name}: score page checksum mismatch')
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if validated_pages is None or digest not in validated_pages:
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check_content(data, path.name)
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if validated_pages is not None:
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validated_pages.add(digest)
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return digest
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