# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443828746 -7200
# Node ID da4132364cfd8e838b5020c2a0f04375d87813ec
# Parent  3a950efbc68f8f732a92692ce0166b06ed712d71
Experiment with replacing colours with black and white.

diff -r 3a950efbc68f -r da4132364cfd optimiser.py
--- a/optimiser.py	Sat Oct 03 00:32:58 2015 +0200
+++ b/optimiser.py	Sat Oct 03 01:32:26 2015 +0200
@@ -52,6 +52,13 @@
 def saturate_value(x, exp):
     return int(127.5 + sign(x - 127.5) * 127.5 * pow(abs(x - 127.5) / 127.5, exp))
 
+def replace(value, values):
+    if value not in values:
+        for i, v in list(enumerate(values))[::-1]:
+            if v != value:
+                values[i] = value
+                return
+
 def test():
     size = 512
     for r in (0, 63, 127, 191, 255):
@@ -135,6 +142,12 @@
         most = [value for n, value in c[:4]]
         least = [value for n, value in c[4:]]
 
+        if least:
+            if (0, 0, 0) in least[:2]:
+                replace((0, 0, 0), most)
+            if (255, 255, 255) in least[:2]:
+                replace((255, 255, 255), most)
+
         for x in range(0, width):
             rgb = im.getpixel((x, y))
 
@@ -144,7 +157,7 @@
             value = get_value(rgb)
             if value in least:
                 rgb = im.getpixel((x, y))
-                value = pattern(value, most)[0][1]
+                value = get_value(value, most)
 
             im.putpixel((x, y), value)