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Running on Zero
Running on Zero
File size: 1,447 Bytes
f44aac9 | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 | #!/usr/bin/env python3
from __future__ import annotations
import random
import struct
import zlib
from pathlib import Path
def main() -> None:
out = Path("static/assets/parchment.png")
out.parent.mkdir(parents=True, exist_ok=True)
write_png(out, 1280, 760)
print(f"wrote {out}")
def write_png(path: Path, width: int, height: int) -> None:
random.seed(47)
rows = []
for y in range(height):
row = bytearray([0])
for x in range(width):
dx = abs(x / width - 0.5)
dy = abs(y / height - 0.5)
vignette = int((dx + dy) * 58)
grain = random.randint(-12, 12)
wave = int(8 * random.random() + 6 * ((x * y) % 17 == 0))
r = clamp(217 - vignette + grain + wave)
g = clamp(190 - vignette + grain)
b = clamp(137 - vignette + grain // 2)
row.extend([r, g, b, 255])
rows.append(bytes(row))
raw = b"".join(rows)
png = b"\x89PNG\r\n\x1a\n"
png += chunk(b"IHDR", struct.pack(">IIBBBBB", width, height, 8, 6, 0, 0, 0))
png += chunk(b"IDAT", zlib.compress(raw, 9))
png += chunk(b"IEND", b"")
path.write_bytes(png)
def chunk(kind: bytes, data: bytes) -> bytes:
return struct.pack(">I", len(data)) + kind + data + struct.pack(">I", zlib.crc32(kind + data) & 0xFFFFFFFF)
def clamp(value: int) -> int:
return max(0, min(255, value))
if __name__ == "__main__":
main()
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