# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443785849 -7200
# Node ID 736979f993792736a288b559217ebfd96474aaf8
# Parent  cd815af3effc57bd3a92b4861b7bb293ac104af3
Experiment with combining more than two colours at once for an input colour.

diff -r cd815af3effc -r 736979f99379 optimiser.py
--- a/optimiser.py	Thu Oct 01 18:39:59 2015 +0200
+++ b/optimiser.py	Fri Oct 02 13:37:29 2015 +0200
@@ -1,6 +1,6 @@
 #!/usr/bin/env python
 
-from random import randint
+from random import random
 from os.path import extsep, splitext
 import EXIF
 import PIL.Image
@@ -17,53 +17,30 @@
     r2, g2, b2 = rgb2
     return math.sqrt(pow(r1 - r2, 2) + pow(g1 - g2, 2) + pow(b1 - b2, 2))
 
-def brightness(rgb):
-    return distance(rgb, (0, 0, 0))
-
-def factor(start, end, rgb):
-    r1, g1, b1 = start
-    r2, g2, b2 = end
-    gr, gg, gb = r2 - r1, g2 - g1, b2 - b1
-    r, g, b = rgb
-    pr, pg, pb = r - r1, g - g1, b - b1
-    dp = pr * gr + pg * gg + pb * gb
-    return dp / pow(distance(start, end), 2)
-
-def darklight(rgb1, rgb2):
-    if brightness(rgb1) <= brightness(rgb2):
-        return rgb1, rgb2
-    else:
-        return rgb2, rgb1
-
-def nearest(rgb, values=None):
-    l = map(lambda c: (distance(rgb, c), c), values or corners)
-    l.sort()
-    return l
+def distribution(rgb, points):
+    l = []
+    total = 0
+    for c in points:
+        d = distance(rgb, c)
+        if d == 0:
+            return [(1, c)]
+        l.append((pow(d, -3), c))
+        total += pow(d, -3)
+    return [(d / total, c) for d, c in l]
 
 def pattern(rgb, values=None):
-    l = nearest(rgb, values)
-    start, end = l[0][1], l[1][1]
-    f = factor(start, end, rgb)
-    #if f > 0.5:
-    #    start, end = end, start
-    #    f = 1 - f
-    return start, end, f
+    l = distribution(rgb, values or corners)
+    l.sort(reverse=True)
+    return l
 
-def choose(seq, f):
-    last = int(seq * f)
-    current = int((seq + 1) * f)
-    return last != current
-
-def get_value(xy, rgb, width, height, values=None):
-    x, y = xy
-    rgb1, rgb2, f = pattern(rgb, values)
-    if choose(x + randint(0, width), f) and choose(y + randint(0, height), f):
-        return rgb2
-    else:
-        return rgb1
-
-def get_best(rgb, values):
-    return nearest(rgb, values)[0][1]
+def get_value(rgb, values=None):
+    choose = random()
+    threshold = 0
+    for f, c in pattern(rgb, values):
+        threshold += f
+        if choose < threshold:
+            return c
+    return c
 
 def sign(x):
     return x >= 0 and 1 or -1
@@ -80,7 +57,7 @@
         im = PIL.Image.new("RGB", (size, size))
         for g in range(0, size):
             for b in range(0, size):
-                value = get_value((g, b), (r, (g * 256) / size, (b * 256 / size)), size, size)
+                value = get_value((r, (g * 256) / size, (b * 256 / size)))
                 im.putpixel((g, b), value)
         im.save("rgb%d.png" % r)
 
@@ -89,7 +66,7 @@
     im = PIL.Image.new("RGB", (size, size))
     for y in range(0, size):
         for x in range(0, size):
-            im.putpixel((x, y), get_value((x, y), rgb, size, size))
+            im.putpixel((x, y), get_value(rgb))
     im.save("rgb%02d%02d%02d.png" % rgb)
 
 def rotate_and_scale(im, width, height, rotate):
@@ -125,7 +102,7 @@
     desaturate = sys.argv[3:].count("-d")
 
     x = EXIF.process_file(open(input_filename))
-    im = PIL.Image.open(input_filename)
+    im = PIL.Image.open(input_filename).convert("RGB")
     im = rotate_and_scale(im, width, height, rotate)
 
     if preview:
@@ -148,7 +125,7 @@
 
             # Count the number of requested colours.
 
-            value = get_value((x, y), rgb, width, height)
+            value = get_value(rgb)
             if not c.has_key(value):
                 c[value] = 1
             else:
@@ -174,9 +151,9 @@
             # Get the requested colours and choose the closest alternative for
             # less common colours.
 
-            value = get_value((x, y), rgb, width, height)
+            value = get_value(rgb)
             if value in least:
-                value = get_value((x, y), rgb, width, height, most)
+                value = get_value(rgb, most)
             im.putpixel((x, y), value)
 
     im.save(output_filename)