Cacher is the code snippet organizer for pro developers

#!/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"
    else:
        return u"48;5;%d" % c

def cc2fg(c):
    if c == -1:
        return u"38;5;0"
    else:
        return u"38;5;%d" % c

def main():
    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.buffer,
                        help='output file to process (defaults to stdout)')
    parser.add_argument('--dither', '-d', action='store_true',
                    help='use floyd-steinberg dithering')
    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))

    palette_img = Image.new('P', (1, 1))
    palette_img.putpalette(xterm256colors)

    # evil undocumented PIL internals to get it to use our palette
    try:
        cons = img._makeself
    except AttributeError:
        cons = img._new

    img8 = cons(img.im.convert('P', args.dither, palette_img.im))

    tf = codecs.getwriter('utf8')(args.output)
    lastcc, lastfg, lastbg = None, None, None
    for y in range(0, h, 2):
        for x in range(w):
            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 ' % cc2bg(cc[0]))
                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, None

    tf.close()

if __name__ == '__main__':
    main()