|  | #!C:\odoobuild\WinPy64\python-3.12.3.amd64\python.exe
# pripalpng
"""Convert to Palette PNG (without changing colours)"""
import argparse
import collections
# https://docs.python.org/2.7/library/io.html
import io
import string
import zlib
# Local module.
import png
def make_inverse_palette(rows, channels):
    """
    The inverse palette maps from tuple to palette index.
    """
    palette = {}
    for row in rows:
        for pixel in png.group(row, channels):
            if pixel in palette:
                continue
            palette[pixel] = len(palette)
    return palette
def palette_convert(out, inp, palette_file):
    """
    Convert PNG image in `inp` to use a palette, colour type 3,
    and write converted image to `out`.
    `palette_file` is a file descriptor for the palette to use.
    If `palette_file` is None, then `inp` is used as the palette.
    """
    if palette_file is None:
        inp, palette_file = palette_file, inp
    reader = png.Reader(file=palette_file)
    w, h, rows, info = asRGBorA8(reader)
    channels = info["planes"]
    if not inp:
        rows = list(rows)
    palette_map = make_inverse_palette(rows, channels)
    if inp:
        reader = png.Reader(file=inp)
        w, h, rows, info = asRGBorA8(reader)
        channels = info["planes"]
    # Default for colours not in palette is to use last entry.
    last = len(palette_map) - 1
    def map_pixel(p):
        return palette_map.get(p, last)
    def convert_rows():
        for row in rows:
            yield [map_pixel(p) for p in png.group(row, channels)]
    # Make a palette by sorting the pixels according to their index.
    palette = sorted(palette_map.keys(), key=palette_map.get)
    pal_info = dict(size=info["size"], palette=palette)
    w = png.Writer(**pal_info)
    w.write(out, convert_rows())
def asRGBorA8(reader):
    """
    Return (width, height, rows, info) converting to RGB,
    or RGBA if original has an alpha channel.
    """
    _, _, _, info = reader.read()
    if info["alpha"]:
        return reader.asRGBA8()
    else:
        return reader.asRGB8()
def main(argv=None):
    import sys
    import re
    if argv is None:
        argv = sys.argv
    argv = argv[1:]
    parser = argparse.ArgumentParser(description=__doc__)
    parser.add_argument("--palette", type=png.cli_open)
    parser.add_argument(
        "input", nargs="?", default="-", type=png.cli_open, metavar="PNG"
    )
    args = parser.parse_args(argv)
    palette_convert(png.binary_stdout(), args.input, args.palette)
if __name__ == "__main__":
    main()
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