34 lines
1.1 KiB
Python
34 lines
1.1 KiB
Python
"""Generate solid-color PNG icons for PWA manifest using stdlib only (no Pillow)."""
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import zlib
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import struct
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import os
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def make_png(size, rgb=(0x25, 0x63, 0xEB)):
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"""Create a minimal valid RGB PNG of the given size filled with one color."""
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w = h = size
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raw = b''
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for _ in range(h):
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raw += b'\x00' + bytes(rgb) * w # filter byte 0 (None) + RGB pixels
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compressed = zlib.compress(raw, 9)
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def chunk(name, data):
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c = name + data
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return struct.pack('>I', len(data)) + c + struct.pack('>I', zlib.crc32(c) & 0xffffffff)
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sig = b'\x89PNG\r\n\x1a\n'
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ihdr = chunk(b'IHDR', struct.pack('>IIBBBBB', w, h, 8, 2, 0, 0, 0))
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idat = chunk(b'IDAT', compressed)
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iend = chunk(b'IEND', b'')
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return sig + ihdr + idat + iend
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if __name__ == '__main__':
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out_dir = os.path.join(os.path.dirname(__file__), '..', 'static')
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os.makedirs(out_dir, exist_ok=True)
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for size in [192, 512]:
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path = os.path.join(out_dir, f'icon-{size}.png')
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with open(path, 'wb') as f:
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f.write(make_png(size))
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print(f'Wrote {path}')
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