Image to xterm-256 Unicode block art converter

xt256img.py

#!/usr/bin/env python3
from __future__ import print_function
import sys, argparse, codecs
from PIL import Image, ImagePalette

xterm256colors = [ # http://pln.jonas.me/xterm-colors
    0x00, 0x00, 0x00, 0x80, 0x00, 0x00, 0x00, 0x80, 0x00, 0x80, 0x80, 0x00,
    0x00, 0x00, 0x80, 0x80, 0x00, 0x80, 0x00, 0x80, 0x80, 0xc0, 0xc0, 0xc0,
    0x80, 0x80, 0x80, 0xff, 0x00, 0x00, 0x00, 0xff, 0x00, 0xff, 0xff, 0x00,
    0x00, 0x00, 0xff, 0xff, 0x00, 0xff, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff,
    0x00, 0x00, 0x00, 0x00, 0x00, 0x5f, 0x00, 0x00, 0x87, 0x00, 0x00, 0xaf,
    0x00, 0x00, 0xd7, 0x00, 0x00, 0xff, 0x00, 0x5f, 0x00, 0x00, 0x5f, 0x5f,
    0x00, 0x5f, 0x87, 0x00, 0x5f, 0xaf, 0x00, 0x5f, 0xd7, 0x00, 0x5f, 0xff,
    0x00, 0x87, 0x00, 0x00, 0x87, 0x5f, 0x00, 0x87, 0x87, 0x00, 0x87, 0xaf,
    0x00, 0x87, 0xd7, 0x00, 0x87, 0xff, 0x00, 0xaf, 0x00, 0x00, 0xaf, 0x5f,
    0x00, 0xaf, 0x87, 0x00, 0xaf, 0xaf, 0x00, 0xaf, 0xd7, 0x00, 0xaf, 0xff,
    0x00, 0xd7, 0x00, 0x00, 0xd7, 0x5f, 0x00, 0xd7, 0x87, 0x00, 0xd7, 0xaf,
    0x00, 0xd7, 0xd7, 0x00, 0xd7, 0xff, 0x00, 0xff, 0x00, 0x00, 0xff, 0x5f,
    0x00, 0xff, 0x87, 0x00, 0xff, 0xaf, 0x00, 0xff, 0xd7, 0x00, 0xff, 0xff,
    0x5f, 0x00, 0x00, 0x5f, 0x00, 0x5f, 0x5f, 0x00, 0x87, 0x5f, 0x00, 0xaf,
    0x5f, 0x00, 0xd7, 0x5f, 0x00, 0xff, 0x5f, 0x5f, 0x00, 0x5f, 0x5f, 0x5f,
    0x5f, 0x5f, 0x87, 0x5f, 0x5f, 0xaf, 0x5f, 0x5f, 0xd7, 0x5f, 0x5f, 0xff,
    0x5f, 0x87, 0x00, 0x5f, 0x87, 0x5f, 0x5f, 0x87, 0x87, 0x5f, 0x87, 0xaf,
    0x5f, 0x87, 0xd7, 0x5f, 0x87, 0xff, 0x5f, 0xaf, 0x00, 0x5f, 0xaf, 0x5f,
    0x5f, 0xaf, 0x87, 0x5f, 0xaf, 0xaf, 0x5f, 0xaf, 0xd7, 0x5f, 0xaf, 0xff,
    0x5f, 0xd7, 0x00, 0x5f, 0xd7, 0x5f, 0x5f, 0xd7, 0x87, 0x5f, 0xd7, 0xaf,
    0x5f, 0xd7, 0xd7, 0x5f, 0xd7, 0xff, 0x5f, 0xff, 0x00, 0x5f, 0xff, 0x5f,
    0x5f, 0xff, 0x87, 0x5f, 0xff, 0xaf, 0x5f, 0xff, 0xd7, 0x5f, 0xff, 0xff,
    0x87, 0x00, 0x00, 0x87, 0x00, 0x5f, 0x87, 0x00, 0x87, 0x87, 0x00, 0xaf,
    0x87, 0x00, 0xd7, 0x87, 0x00, 0xff, 0x87, 0x5f, 0x00, 0x87, 0x5f, 0x5f,
    0x87, 0x5f, 0x87, 0x87, 0x5f, 0xaf, 0x87, 0x5f, 0xd7, 0x87, 0x5f, 0xff,
    0x87, 0x87, 0x00, 0x87, 0x87, 0x5f, 0x87, 0x87, 0x87, 0x87, 0x87, 0xaf,
    0x87, 0x87, 0xd7, 0x87, 0x87, 0xff, 0x87, 0xaf, 0x00, 0x87, 0xaf, 0x5f,
    0x87, 0xaf, 0x87, 0x87, 0xaf, 0xaf, 0x87, 0xaf, 0xd7, 0x87, 0xaf, 0xff,
    0x87, 0xd7, 0x00, 0x87, 0xd7, 0x5f, 0x87, 0xd7, 0x87, 0x87, 0xd7, 0xaf,
    0x87, 0xd7, 0xd7, 0x87, 0xd7, 0xff, 0x87, 0xff, 0x00, 0x87, 0xff, 0x5f,
    0x87, 0xff, 0x87, 0x87, 0xff, 0xaf, 0x87, 0xff, 0xd7, 0x87, 0xff, 0xff,
    0xaf, 0x00, 0x00, 0xaf, 0x00, 0x5f, 0xaf, 0x00, 0x87, 0xaf, 0x00, 0xaf,
    0xaf, 0x00, 0xd7, 0xaf, 0x00, 0xff, 0xaf, 0x5f, 0x00, 0xaf, 0x5f, 0x5f,
    0xaf, 0x5f, 0x87, 0xaf, 0x5f, 0xaf, 0xaf, 0x5f, 0xd7, 0xaf, 0x5f, 0xff,
    0xaf, 0x87, 0x00, 0xaf, 0x87, 0x5f, 0xaf, 0x87, 0x87, 0xaf, 0x87, 0xaf,
    0xaf, 0x87, 0xd7, 0xaf, 0x87, 0xff, 0xaf, 0xaf, 0x00, 0xaf, 0xaf, 0x5f,
    0xaf, 0xaf, 0x87, 0xaf, 0xaf, 0xaf, 0xaf, 0xaf, 0xd7, 0xaf, 0xaf, 0xff,
    0xaf, 0xd7, 0x00, 0xaf, 0xd7, 0x5f, 0xaf, 0xd7, 0x87, 0xaf, 0xd7, 0xaf,
    0xaf, 0xd7, 0xd7, 0xaf, 0xd7, 0xff, 0xaf, 0xff, 0x00, 0xaf, 0xff, 0x5f,
    0xaf, 0xff, 0x87, 0xaf, 0xff, 0xaf, 0xaf, 0xff, 0xd7, 0xaf, 0xff, 0xff,
    0xd7, 0x00, 0x00, 0xd7, 0x00, 0x5f, 0xd7, 0x00, 0x87, 0xd7, 0x00, 0xaf,
    0xd7, 0x00, 0xd7, 0xd7, 0x00, 0xff, 0xd7, 0x5f, 0x00, 0xd7, 0x5f, 0x5f,
    0xd7, 0x5f, 0x87, 0xd7, 0x5f, 0xaf, 0xd7, 0x5f, 0xd7, 0xd7, 0x5f, 0xff,
    0xd7, 0x87, 0x00, 0xd7, 0x87, 0x5f, 0xd7, 0x87, 0x87, 0xd7, 0x87, 0xaf,
    0xd7, 0x87, 0xd7, 0xd7, 0x87, 0xff, 0xd7, 0xaf, 0x00, 0xd7, 0xaf, 0x5f,
    0xd7, 0xaf, 0x87, 0xd7, 0xaf, 0xaf, 0xd7, 0xaf, 0xd7, 0xd7, 0xaf, 0xff,
    0xd7, 0xd7, 0x00, 0xd7, 0xd7, 0x5f, 0xd7, 0xd7, 0x87, 0xd7, 0xd7, 0xaf,
    0xd7, 0xd7, 0xd7, 0xd7, 0xd7, 0xff, 0xd7, 0xff, 0x00, 0xd7, 0xff, 0x5f,
    0xd7, 0xff, 0x87, 0xd7, 0xff, 0xaf, 0xd7, 0xff, 0xd7, 0xd7, 0xff, 0xff,
    0xff, 0x00, 0x00, 0xff, 0x00, 0x5f, 0xff, 0x00, 0x87, 0xff, 0x00, 0xaf,
    0xff, 0x00, 0xd7, 0xff, 0x00, 0xff, 0xff, 0x5f, 0x00, 0xff, 0x5f, 0x5f,
    0xff, 0x5f, 0x87, 0xff, 0x5f, 0xaf, 0xff, 0x5f, 0xd7, 0xff, 0x5f, 0xff,
    0xff, 0x87, 0x00, 0xff, 0x87, 0x5f, 0xff, 0x87, 0x87, 0xff, 0x87, 0xaf,
    0xff, 0x87, 0xd7, 0xff, 0x87, 0xff, 0xff, 0xaf, 0x00, 0xff, 0xaf, 0x5f,
    0xff, 0xaf, 0x87, 0xff, 0xaf, 0xaf, 0xff, 0xaf, 0xd7, 0xff, 0xaf, 0xff,
    0xff, 0xd7, 0x00, 0xff, 0xd7, 0x5f, 0xff, 0xd7, 0x87, 0xff, 0xd7, 0xaf,
    0xff, 0xd7, 0xd7, 0xff, 0xd7, 0xff, 0xff, 0xff, 0x00, 0xff, 0xff, 0x5f,
    0xff, 0xff, 0x87, 0xff, 0xff, 0xaf, 0xff, 0xff, 0xd7, 0xff, 0xff, 0xff,
    0x08, 0x08, 0x08, 0x12, 0x12, 0x12, 0x1c, 0x1c, 0x1c, 0x26, 0x26, 0x26,
    0x30, 0x30, 0x30, 0x3a, 0x3a, 0x3a, 0x44, 0x44, 0x44, 0x4e, 0x4e, 0x4e,
    0x58, 0x58, 0x58, 0x62, 0x62, 0x62, 0x6c, 0x6c, 0x6c, 0x76, 0x76, 0x76,
    0x80, 0x80, 0x80, 0x8a, 0x8a, 0x8a, 0x94, 0x94, 0x94, 0x9e, 0x9e, 0x9e,
    0xa8, 0xa8, 0xa8, 0xb2, 0xb2, 0xb2, 0xbc, 0xbc, 0xbc, 0xc6, 0xc6, 0xc6,
    0xd0, 0xd0, 0xd0, 0xda, 0xda, 0xda, 0xe4, 0xe4, 0xe4, 0xee, 0xee, 0xee,
]

def cc2bg(c):
    if c == -1:
        return u"49"
    elif isinstance(c, int):
        return u"48;5;%d" % c
    elif len(c) == 3:
        return u"48;2;%d;%d;%d" % (c[0], c[1], c[2])
    else:
        return u"48;5;%d" % c

def cc2fg(c):
    if c == -1:
        return u"38;5;0"
    elif isinstance(c, int):
        return u"38;5;%d" % c
    elif len(c) == 3:
        return u"38;2;%d;%d;%d" % (c[0], c[1], c[2])
    else:
        return u"38;5;%d" % c

def main():
    try:
        sys.stdin = sys.stdin.buffer
    except AttributeError:
        pass

    parser = argparse.ArgumentParser(description='Convert images into xterm-256color maps.')
    parser.add_argument('input', metavar='INPUT', type=argparse.FileType('rb'),
                        help='the input image to process (- for stdin)')
    parser.add_argument('output', metavar='OUTPUT', type=argparse.FileType('wb'),
                        nargs='?', default=sys.stdout,
                        help='output file to process (defaults to stdout)')
    parser.add_argument('--dither', '-d', action='store_true',
                    help='use floyd-steinberg dithering')
    parser.add_argument('--truecolor', '-t', action='store_true',
                    help='use true-color output')
    parser.add_argument('--upper', '-u', action='store_true',
                    help=('use U+2580 UPPER HALF BLOCK for lower half-transparent pixels'
                          ' - this doesn\'t always render correctly'))
    args = parser.parse_args()

    img = Image.open(args.input).convert('RGBA')
    if img.size[0] * img.size[1] > 280 * 160:
        print('Warning: Big image, did you forget to scale it down?', file=sys.stderr)

    w, h = img.size
    if h & 1:
        h += 1
        i2 = img
        img = Image.new('RGBA', (w, h))
        img.paste(i2, (0, 0))

    if not args.truecolor:
        palette_img = Image.new('P', (1, 1))
        palette_img.putpalette(xterm256colors)

        # evil undocumented PIL internals to get it to use our palette
        img8 = img._new(img.im.convert('P', args.dither, palette_img.im))

    # make the encoding stuff work for both stdout and files in Python2 and 3.
    tf = args.output
    try:
        if tf.encoding is None:
            tf = codecs.getwriter('utf8')(tf)
    except AttributeError:
        tf = codecs.getwriter('utf8')(tf)
    lastcc, lastfg, lastbg = None, None, None
    for y in range(0, h, 2):
        for x in range(w):
            if args.truecolor:
                cc = [img.getpixel((x, y))[:3], img.getpixel((x, y+1))[:3]]
            else:
                cc = [img8.getpixel((x, y)), img8.getpixel((x, y+1))]
            a0, a1 = img.getpixel((x, y))[3], img.getpixel((x, y+1))[3]
            if a0 == 0:
                cc[0] = -1
            if a1 == 0:
                cc[1] = -1

            if cc == lastcc:
                tf.write(char)
            elif cc[0] == cc[1]:
                char = u' '
                if lastbg != cc[0]:
                    tf.write(u'\x1b[%sm%s' % (cc2bg(cc[0]), char))
                else:
                    tf.write(char)
                lastbg = cc[0]
            # Due to font rendering stupidity, this doesn't work as well as it
            # should (see -u). This is for optimization only, so meh.
            #elif lastcc == cc[::-1]:
                #char = u'\u2584' if char == u'\u2580' else u'\u2580'
                #tf.write(char)
            else:
                if cc[1] == -1 and args.upper:
                    fg, bg = cc
                    char = u'\u2580'
                else:
                    bg, fg = cc
                    char = u'\u2584'
                if lastfg == fg:
                    tf.write(u'\x1b[%sm%s' % (cc2bg(bg), char))
                elif lastbg == bg:
                    tf.write(u'\x1b[%sm%s' % (cc2fg(fg), char))
                else:
                    tf.write(u'\x1b[%s;%sm%s' % (cc2fg(fg), cc2bg(bg), char))
                lastfg, lastbg = fg, bg
            lastcc = cc
        tf.write(u'\x1b[0m\n')
        lastcc, lastfg, lastbg = (-1, -1), None, -1

    tf.close()

if __name__ == '__main__':
    main()

Does it work with you now @ledlamp?