icotocur.py

#!/usr/bin/python3
import argparse
import struct
import sys


def icotocur(buff, hotx, hoty):
    """Updates buff from ico to cur format with hotpots as a multiplier."""
    assert 0 <= hotx <= 1 and 0 <= hoty <= 1
    buff = bytearray(buff)
    buff[2:4] = struct.pack('H', 2)
    first_offset = struct.unpack('<HHHBBBBHHII', buff[:22])[10]
    for x in range(6, first_offset, 16):
        props = list(struct.unpack('<BBBBHHII', buff[x:x + 16]))
        props[4] = int(round(props[0] * hotx))
        props[5] = int(round(props[0] * hoty))
        buff[x:x + 16] = struct.pack('<BBBBHHII', *props)
    return bytes(buff)


def main():
    parser = argparse.ArgumentParser(description="Convert ico files to cur files.")
    parser.add_argument("hotx", type=float, help="0.0 <= hotx <= 1.0")
    parser.add_argument("hoty", type=float, help="0.0 <= hoty <= 1.0")
    args = parser.parse_args()
    # Read buffer from stdin and write to stdout
    sys.stdout.buffer.write(icotocur(sys.stdin.buffer.read(), args.hotx, args.hoty))


if __name__ == "__main__":
    main()