49 lines
1.8 KiB
Python
49 lines
1.8 KiB
Python
"""浏览器合成海报的文件与尺寸校验。"""
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import io
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from PIL import Image
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from insurance.poster.format_registry import list_poster_formats
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class PosterRenderValidationError(ValueError):
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"""最终海报文件不符合格式契约。"""
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def validate_rendered_png(image_bytes: bytes, format_id: str) -> dict:
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"""完整解码 PNG，并验证其真实像素尺寸。"""
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format_spec = next(
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(item for item in list_poster_formats() if item["id"] == format_id),
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None,
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)
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if not format_spec:
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raise PosterRenderValidationError(f"不支持的海报格式: {format_id}")
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try:
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with Image.open(io.BytesIO(image_bytes)) as image:
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image.verify()
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with Image.open(io.BytesIO(image_bytes)) as image:
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image.load()
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width, height = image.size
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image_format = image.format
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except Exception as exc:
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raise PosterRenderValidationError("PNG 文件无法解码或已经损坏") from exc
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if image_format != "PNG":
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raise PosterRenderValidationError("最终海报必须是 PNG 格式")
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expected = format_spec["output"]
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if width != expected["width"]:
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raise PosterRenderValidationError(
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f"海报宽度不匹配，应为 {expected['width']}px，实际为 {width}px"
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)
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if expected["height"] is not None and height != expected["height"]:
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raise PosterRenderValidationError(
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f"海报尺寸不匹配，应为 {expected['width']}×{expected['height']}，"
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f"实际为 {width}×{height}"
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)
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if expected["height"] is None and not 1 <= height <= 32767:
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raise PosterRenderValidationError("长图高度超出浏览器安全范围")
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return {"width": width, "height": height, "format": image_format}
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