colorblox.py - converts given image into emoji color blocks

colorblox.py

import sys, os
from PIL import Image


MAX_SIZE = 16 # max output dimension in characters
RESAMPLE_TYPE = Image.NEAREST # alternately, Image.BICUBIC
DITHER_TYPE = Image.NONE # alternately, Image.FLOYDSTEINBERG

TRANSP = (0, 0, 0, 0)
RED = (221, 46, 68, 255)
ORANGE = (244, 144, 12, 255)
YELLOW = (253, 203, 88, 255)
GREEN = (120, 177, 89, 255)
BLUE = (85, 172, 238, 255)
PURPLE = (170, 142, 214, 255)
BROWN = (193, 105, 79, 255)
BLACK = (65, 65, 65, 255)
WHITE = (243, 243, 243, 255)
COLORS = [TRANSP, RED, ORANGE, YELLOW, GREEN, BLUE, PURPLE, BROWN, BLACK, WHITE]
# different "blank" characters work better with different fonts :/
#TRANSP_CHAR = ' ' # regular ol' space
#TRANSP_CHAR = ' ' # U+2003 "em space"
#TRANSP_CHAR = '​' # U+200B "zero width sapce"
TRANSP_CHAR = '　' # U+3000 "ideographic space" - still not the same size as a color block in many fonts :[
CHARS = [TRANSP_CHAR, '🟥', '🟧', '🟨', '🟩', '🟦', '🟪', '🟫', '⬛', '⬜']


if __name__ == '__main__':
    if len(sys.argv) <= 1:
        print('Please specify an image.')
        sys.exit()
    filename = ' '.join(sys.argv[1:])
    if not os.path.exists(filename):
        print("Couldn't find image file %s" % filename)
        sys.exit()
    # build palette
    pal_img = Image.new('P', (1, 1))
    # pal = [*(c[0], c[1], c[2]) for c in COLORS] # "iterable unpacking cannot be used in comprehension" :[
    pal = []
    for c in COLORS:
        pal += [c[0], c[1], c[2], c[3]]
    # PIL will fill out <256 color palettes with bogus values :/
    while len(pal) < 256 * 4:
        for i in range(4):
            pal.append(0)
    # palette for PIL must be exactly 256 colors
    pal = pal[:256*4]
    pal_img.putpalette(pal, rawmode='RGBA') 
    try:
        src_img = Image.open(filename)
        src_img = src_img.convert('RGB')
        src_w, src_h = src_img.size
        if src_w >= src_h:
            aspect = src_h / src_w
            w = MAX_SIZE
            h = int(w * aspect)
        else:
            aspect = src_w / src_h
            h = MAX_SIZE
            w = int(h * aspect)
        src_img = src_img.resize((w, h), resample=RESAMPLE_TYPE)
        src_img = src_img.quantize(colors=len(COLORS), palette=pal_img, dither=DITHER_TYPE)
    except:
        print('Failed opening image %s' % filename)
        sys.exit()
    for y in range(h):
        line = ''
        for x in range(w):
            p = src_img.getpixel((x, y))
            line += CHARS[p]
        print(line)
    print(filename)
    print('%s x %s -> %s x %s (%s chars total)' % (src_w, src_h, w, h, w * h))