1 #!/usr/bin/env python 2 3 from array import array 4 from itertools import combinations 5 import PIL.Image 6 import sys 7 8 def scale(v): 9 return (v + 64) / 128 10 11 def point(rgb): 12 return tuple(map(scale, rgb)) 13 14 def index(p): 15 return p[0] * 9 + p[1] * 3 + p[2] 16 17 def colour(i): 18 return (255 * (i % 2), 255 * ((i / 2) % 2), 255 * ((i / 4) % 2)) 19 20 def add(d, v): 21 d[v] = (d.has_key(v) and d[v] or 0) + 1 22 23 def by_frequency(d): 24 l = [(f, t) for (t, f) in d.items()] 25 l.sort(reverse=True) 26 return [i[1] for i in l] 27 28 def match(b, bases): 29 return b in bases and b 30 31 def match_lighter(b, bases): 32 return upward[b] in bases and upward[b] 33 34 def match_darker(b, bases): 35 return downward[b] in bases and downward[b] 36 37 def fallback(bases): 38 for b in by_frequency(bases): 39 if b not in ["_", "W"]: 40 return b 41 return by_frequency(bases)[0] 42 43 tones = [ 44 "___", "_BB", "BBB", # 00x 45 "_GG", "_CC", "BCC", # 01x 46 "GGG", "GCC", "CCC", # 02x 47 "_RR", "_MM", "BMM", # 10x 48 "_YY", "_*W", "BBW", # 11x 49 "GYY", "GGW", "CCW", # 12x 50 "RRR", "RMM", "MMM", # 20x 51 "RYY", "RRW", "MMW", # 21x 52 "YYY", "YYW", "WWW", # 22x 53 ] 54 55 colours = ["_", "R", "G", "Y", "B", "M", "C", "W"] 56 57 if __name__ == "__main__": 58 width = 320 59 input_filename, output_filename = sys.argv[1:3] 60 61 im = PIL.Image.open(input_filename) 62 w, h = im.size 63 height = (width * h) / w 64 im = im.resize((width, height)) 65 66 usage = [] 67 base_usage = [] 68 toned = [] 69 70 for row in range(0, height): 71 u = {} 72 usage.append(u) 73 bu = {} 74 base_usage.append(bu) 75 tr = [] 76 toned.append(tr) 77 for column in range(0, width): 78 rgb = im.getpixel((column, row)) 79 p = point(rgb) 80 i = index(p) 81 t = tones[i] 82 add(u, t) 83 if t[0] != "*": 84 add(bu, t[0]) 85 if t[1] != "*": 86 add(bu, t[1]) 87 if t[2] != "*": 88 add(bu, t[2]) 89 tr.append(t) 90 91 chosen = [] 92 93 for row, (u, bu) in enumerate(zip(usage, base_usage)): 94 light = row % 2 95 best = 0 96 best_bases = None 97 best_missing = None 98 best_map = None 99 for bases in combinations(bu, 4): 100 bases = dict([(base, bu[base]) for base in bases]) 101 count = 0 102 missing = [] 103 tone_map = {} 104 for tone, freq in u.items(): 105 base = match(tone[1], bases) or match(light and tone[2] or tone[0], bases) 106 if base: 107 tone_map[tone] = base 108 count += freq 109 else: 110 missing.append(tone) 111 if count > best: 112 best_bases = bases 113 best_missing = missing 114 best_map = tone_map 115 best = count 116 chosen.append((best, best_bases or bases, best_map or tone_map, best_missing or missing)) 117 118 output = [] 119 120 for row, (tr, ch) in enumerate(zip(toned, chosen)): 121 o = [] 122 for column, t in enumerate(tr): 123 best, bases, tone_map, missing = ch 124 base = tone_map.get(t) or fallback(bases) 125 o.append(base) 126 i = colours.index(base) 127 im.putpixel((column, row), colour(i)) 128 129 output.append("".join(o)) 130 131 im.save(output_filename) 132 133 # vim: tabstop=4 expandtab shiftwidth=4