PaletteOptimiser

optimiser.py

45:8e6788e5694a
2015-10-04 Paul Boddie Merged branches.
     1 #!/usr/bin/env python     2      3 from random import random, randrange     4 from os.path import splitext     5 import EXIF     6 import PIL.Image     7 import itertools     8 import math     9 import sys    10     11 corners = [    12     (0, 0, 0), (255, 0, 0), (0, 255, 0), (255, 255, 0),    13     (0, 0, 255), (255, 0, 255), (0, 255, 255), (255, 255, 255)    14     ]    15     16 def distance(rgb1, rgb2):    17     r1, g1, b1 = rgb1    18     r2, g2, b2 = rgb2    19     return math.sqrt(pow(r1 - r2, 2) + pow(g1 - g2, 2) + pow(b1 - b2, 2))    20     21 def nearest(rgb, values):    22     l = [(distance(rgb, value), value) for value in values]    23     l.sort()    24     return l[0][1]    25     26 def restore(srgb):    27     return tuple(map(lambda x: int(x * 255.0), srgb))    28     29 def scale(rgb):    30     return tuple(map(lambda x: x / 255.0, rgb))    31     32 def square(srgb):    33     return tuple(map(lambda x: pow(x, 2), srgb))    34     35 def invert(srgb):    36     return tuple(map(lambda x: 1.0 - x, srgb))    37     38 def combination(rgb):    39     rgb = square(scale(rgb))    40     rgbi = invert(rgb)    41     pairs = zip(rgbi, rgb)    42     d = []    43     for corner in corners:    44         rs, gs, bs = scale(corner)    45         d.append((pairs[0][int(rs)] * pairs[1][int(gs)] * pairs[2][int(bs)], corner))    46     return balance(d)    47     48 def complements(rgb):    49     r, g, b = rgb    50     return rgb, restore(invert(scale(rgb)))    51     52 def balance(d):    53     d = dict([(value, f) for f, value in d])    54     for primary, secondary in map(complements, [(255, 0, 0), (0, 255, 0), (0, 0, 255)]):    55         common = min(d[primary], d[secondary])    56         d[primary] -= common    57         d[secondary] -= common    58         d[(0, 0, 0)] += common    59         d[(255, 255, 255)] += common    60     return [(f, value) for value, f in d.items()]    61     62 def combine(d):    63     out = [0, 0, 0]    64     for v, rgb in d:    65         out[0] += v * rgb[0]    66         out[1] += v * rgb[1]    67         out[2] += v * rgb[2]    68     return out    69     70 def pattern(rgb):    71     l = combination(rgb)    72     l.sort(reverse=True)    73     return l    74     75 def get_value(rgb):    76     choose = random()    77     threshold = 0    78     for f, c in pattern(rgb):    79         threshold += f    80         if choose < threshold:    81             return c    82     return c    83     84 def sign(x):    85     return x >= 0 and 1 or -1    86     87 def saturate_rgb(rgb, exp):    88     return tuple([saturate_value(x, exp) for x in rgb])    89     90 def saturate_value(x, exp):    91     return int(127.5 + sign(x - 127.5) * 127.5 * pow(abs(x - 127.5) / 127.5, exp))    92     93 def replace(value, values):    94     if value not in values:    95         for i, v in list(enumerate(values))[::-1]:    96             if v != value:    97                 values[i] = value    98                 return    99    100 def test():   101     size = 512   102     for r in (0, 63, 127, 191, 255):   103         im = PIL.Image.new("RGB", (size, size))   104         for g in range(0, size):   105             for b in range(0, size):   106                 value = get_value((r, (g * 256) / size, (b * 256 / size)))   107                 im.putpixel((g, b), value)   108         im.save("rgb%d.png" % r)   109    110 def test_flat(rgb):   111     size = 64   112     im = PIL.Image.new("RGB", (size, size))   113     for y in range(0, size):   114         for x in range(0, size):   115             im.putpixel((x, y), get_value(rgb))   116     im.save("rgb%02d%02d%02d.png" % rgb)   117    118 def rotate_and_scale(im, width, height, rotate):   119     if rotate or x and x["Image Orientation"].values == [6L]:   120         im = im.rotate(270)   121    122     w, h = im.size   123     if w > h:   124         height = (width * h) / w   125     else:   126         width = (height * w) / h   127    128     return im.resize((width, height))   129    130 if __name__ == "__main__":   131     if "--test" in sys.argv:   132         test()   133         sys.exit(0)   134     elif "--test-flat" in sys.argv:   135         test_flat((120, 40, 60))   136         sys.exit(0)   137    138     width = 320   139     height = 256   140    141     input_filename, output_filename = sys.argv[1:3]   142     basename, ext = splitext(output_filename)   143     preview_filename = "".join([basename + "_preview", ext])   144    145     rotate = "-r" in sys.argv[3:]   146     saturate = sys.argv[3:].count("-s")   147     desaturate = sys.argv[3:].count("-d")   148     preview = "-p" in sys.argv[3:]   149    150     x = EXIF.process_file(open(input_filename))   151     im = PIL.Image.open(input_filename).convert("RGB")   152     im = rotate_and_scale(im, width, height, rotate)   153    154     width, height = im.size   155    156     colours = []   157    158     for y in range(0, height):   159         c = {}   160         for x in range(0, width):   161             rgb = im.getpixel((x, y))   162    163             # Saturate if requested.   164    165             if saturate or desaturate:   166                 rgb = saturate_rgb(rgb, saturate and math.pow(0.5, saturate) or math.pow(2, desaturate))   167                 im.putpixel((x, y), rgb)   168    169             # Sum the colour probabilities.   170    171             for f, value in combination(rgb):   172                 if not c.has_key(value):   173                     c[value] = f   174                 else:   175                     c[value] += f   176    177         c = [(n/width, value) for value, n in c.items()]   178         c.sort(reverse=True)   179         colours.append(c)   180    181     if preview:   182         imp = im.copy()   183         for y in range(0, height):   184             for x in range(0, width):   185                 rgb = imp.getpixel((x, y))   186                 value = get_value(rgb)   187                 imp.putpixel((x, y), value)   188         imp.save(preview_filename)   189    190     for y, c in enumerate(colours):   191         most = [value for n, value in c[:4]]   192         least = [value for n, value in c[4:]]   193    194         if least:   195             switched = []   196             for j in 1, 2:   197                 i = randrange(0, 4)   198                 n, value = c[i]   199                 if n < 0.1:   200                     switched.append(c[i])   201                     del c[i]   202             c += switched   203             most = [value for n, value in c[:4]]   204             least = [value for n, value in c[4:]]   205    206         for x in range(0, width):   207             rgb = im.getpixel((x, y))   208    209             # Get the requested colours and choose the closest alternative for   210             # less common colours.   211    212             value = get_value(rgb)   213             if value in least:   214                 value = nearest(value, most)   215    216             im.putpixel((x, y), value)   217    218     im.save(output_filename)   219    220 # vim: tabstop=4 expandtab shiftwidth=4