# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443696655 -7200
# Node ID c768f24e5233faecb78a5fa97f1759bed9c2baac
# Parent  aabad380ed5941da6bfa64f40abb2d671613aa18
Choose the nearest alternative colours to the original colour.

diff -r aabad380ed59 -r c768f24e5233 optimiser.py
--- a/optimiser.py	Thu Oct 01 02:37:54 2015 +0200
+++ b/optimiser.py	Thu Oct 01 12:50:55 2015 +0200
@@ -40,8 +40,8 @@
     l.sort()
     return l
 
-def pattern(rgb):
-    l = nearest(rgb)
+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:
@@ -54,9 +54,9 @@
     current = int((seq + 1) * math.sqrt(f))
     return last != current
 
-def get_value(xy, rgb, width, height):
+def get_value(xy, rgb, width, height, values=None):
     x, y = xy
-    rgb1, rgb2, f = pattern(rgb)
+    rgb1, rgb2, f = pattern(rgb, values)
     if choose(x + randint(0, width), f) and choose(y + randint(0, height), f):
         return rgb2
     else:
@@ -72,7 +72,7 @@
     return tuple([saturate_value(x, exp) for x in rgb])
 
 def saturate_value(x, exp):
-    return 127.5 + sign(x - 127.5) * 127.5 * pow(abs(x - 127.5) / 127.5, exp)
+    return int(127.5 + sign(x - 127.5) * 127.5 * pow(abs(x - 127.5) / 127.5, exp))
 
 def test():
     size = 512
@@ -132,29 +132,39 @@
         c = {}
         for x in range(0, width):
             rgb = im.getpixel((x, y))
+
+            # Saturate if requested.
+
             if saturate or desaturate:
                 rgb = saturate_rgb(rgb, saturate and math.pow(0.5, saturate) or math.pow(2, desaturate))
+                im.putpixel((x, y), rgb)
+
+            # Count the number of requested colours.
+
             value = get_value((x, y), rgb, width, height)
-            im.putpixel((x, y), value)
             if not c.has_key(value):
                 c[value] = 1
             else:
                 c[value] += 1
+
         c = [(n, value) for value, n in c.items()]
         c.sort(reverse=True)
         colours.append(c)
 
     for y, c in enumerate(colours):
-        if len(c) <= 4:
-            continue
         most = [value for n, value in c[:4]]
         least = [value for n, value in c[4:]]
 
         for x in range(0, width):
             rgb = im.getpixel((x, y))
-            if rgb in least:
-                value = get_best(rgb, most)
-                im.putpixel((x, y), value)
+
+            # Get the requested colours and choose the closest alternative for
+            # less common colours.
+
+            value = get_value((x, y), rgb, width, height)
+            if value in least:
+                value = get_value((x, y), rgb, width, height, most)
+            im.putpixel((x, y), value)
 
     im.save(output_filename)