112 lines
2.5 KiB
Python
Executable File
112 lines
2.5 KiB
Python
Executable File
#!/home/mongar/Escritorio/pruebas_oc/venv/bin/python3
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# pripalpng
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"""Convert to Palette PNG (without changing colours)"""
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import argparse
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import collections
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# https://docs.python.org/2.7/library/io.html
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import io
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import string
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import zlib
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# Local module.
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import png
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def make_inverse_palette(rows, channels):
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"""
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The inverse palette maps from tuple to palette index.
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"""
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palette = {}
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for row in rows:
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for pixel in png.group(row, channels):
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if pixel in palette:
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continue
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palette[pixel] = len(palette)
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return palette
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def palette_convert(out, inp, palette_file):
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"""
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Convert PNG image in `inp` to use a palette, colour type 3,
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and write converted image to `out`.
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`palette_file` is a file descriptor for the palette to use.
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If `palette_file` is None, then `inp` is used as the palette.
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"""
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if palette_file is None:
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inp, palette_file = palette_file, inp
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reader = png.Reader(file=palette_file)
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w, h, rows, info = asRGBorA8(reader)
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channels = info["planes"]
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if not inp:
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rows = list(rows)
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palette_map = make_inverse_palette(rows, channels)
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if inp:
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reader = png.Reader(file=inp)
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w, h, rows, info = asRGBorA8(reader)
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channels = info["planes"]
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# Default for colours not in palette is to use last entry.
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last = len(palette_map) - 1
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def map_pixel(p):
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return palette_map.get(p, last)
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def convert_rows():
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for row in rows:
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yield [map_pixel(p) for p in png.group(row, channels)]
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# Make a palette by sorting the pixels according to their index.
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palette = sorted(palette_map.keys(), key=palette_map.get)
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pal_info = dict(size=info["size"], palette=palette)
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w = png.Writer(**pal_info)
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w.write(out, convert_rows())
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def asRGBorA8(reader):
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"""
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Return (width, height, rows, info) converting to RGB,
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or RGBA if original has an alpha channel.
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"""
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_, _, _, info = reader.read()
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if info["alpha"]:
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return reader.asRGBA8()
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else:
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return reader.asRGB8()
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def main(argv=None):
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import sys
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import re
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if argv is None:
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argv = sys.argv
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argv = argv[1:]
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parser = argparse.ArgumentParser(description=__doc__)
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parser.add_argument("--palette", type=png.cli_open)
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parser.add_argument(
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"input", nargs="?", default="-", type=png.cli_open, metavar="PNG"
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)
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args = parser.parse_args(argv)
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palette_convert(png.binary_stdout(), args.input, args.palette)
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if __name__ == "__main__":
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main()
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