31 lines
935 B
Python
31 lines
935 B
Python
"""Generate solid-colour placeholder PNG icons for the PWA manifest."""
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import struct
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import zlib
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from pathlib import Path
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def _chunk(chunk_type, data):
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c = chunk_type + data
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crc = struct.pack(">I", zlib.crc32(c) & 0xFFFFFFFF)
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return struct.pack(">I", len(data)) + c + crc
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def solid_png(width, height, r, g, b):
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header = b"\x89PNG\r\n\x1a\n"
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ihdr = _chunk(b"IHDR", struct.pack(">IIBBBBB", width, height, 8, 2, 0, 0, 0))
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raw = bytearray()
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for _ in range(height):
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raw.append(0)
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raw.extend(bytes([r, g, b]) * width)
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idat = _chunk(b"IDAT", zlib.compress(bytes(raw)))
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iend = _chunk(b"IEND", b"")
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return header + ihdr + idat + iend
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if __name__ == "__main__":
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dst = Path(__file__).parent
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for size in (192, 512):
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path = dst / f"icon-{size}.png"
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path.write_bytes(solid_png(size, size, 0x1A, 0x1A, 0x2E))
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print(f"Created {path.name} ({size}x{size})")
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