# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1444170948 -7200
# Node ID 2163b1916849b1fd6b67d6d8627150afeebeb8da
# Parent  6adea19bfcc290ccdfeed2d4a5c8182b31ab0201
Cache colour lookup results and avoid unnecessary pixel operations.

diff -r 6adea19bfcc2 -r 2163b1916849 optimiser.py
--- a/optimiser.py	Tue Oct 06 22:22:52 2015 +0200
+++ b/optimiser.py	Wed Oct 07 00:35:48 2015 +0200
@@ -41,15 +41,19 @@
 def invert(srgb):
     return tuple(map(lambda x: 1.0 - x, srgb))
 
+cache = {}
+
 def combination(rgb):
-    rgb = square(scale(rgb))
-    rgbi = invert(rgb)
-    pairs = zip(rgbi, rgb)
-    d = []
-    for corner in corners:
-        rs, gs, bs = scale(corner)
-        d.append((pairs[0][int(rs)] * pairs[1][int(gs)] * pairs[2][int(bs)], corner))
-    return balance(d)
+    if not cache.has_key(rgb):
+        rgb = square(scale(rgb))
+        rgbi = invert(rgb)
+        pairs = zip(rgbi, rgb)
+        d = []
+        for corner in corners:
+            rs, gs, bs = scale(corner)
+            d.append((pairs[0][int(rs)] * pairs[1][int(gs)] * pairs[2][int(bs)], corner))
+        cache[rgb] = balance(d)
+    return cache[rgb]
 
 def complements(rgb):
     r, g, b = rgb
@@ -213,15 +217,12 @@
         if saturate or desaturate or darken or brighten:
             for y in range(0, height):
                 for x in range(0, width):
+                    rgb = im.getpixel((x, y))
                     if saturate or desaturate:
-                        rgb = im.getpixel((x, y))
                         rgb = saturate_rgb(rgb, saturate and math.pow(0.5, saturate) or math.pow(2, desaturate))
-                        im.putpixel((x, y), rgb)
-
                     if darken or brighten:
-                        rgb = im.getpixel((x, y))
                         rgb = amplify_rgb(rgb, brighten and math.pow(0.5, brighten) or math.pow(2, darken))
-                        im.putpixel((x, y), rgb)
+                    im.putpixel((x, y), rgb)
 
     if preview:
         imp = im.copy()