# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443659053 -7200
# Node ID d33be469e542d053c25ae5ef48b4bd9131782e01
# Parent  ac7b9012ab35f99a49021b01d5a35907a8a8e013
Fixed saturation and added desaturation support.

diff -r ac7b9012ab35 -r d33be469e542 optimiser.py
--- a/optimiser.py	Thu Oct 01 02:13:26 2015 +0200
+++ b/optimiser.py	Thu Oct 01 02:24:13 2015 +0200
@@ -68,11 +68,11 @@
 def sign(x):
     return x >= 0 and 1 or -1
 
-def saturate(rgb):
-    return tuple(map(saturate_value, rgb))
+def saturate_rgb(rgb, exp):
+    return tuple([saturate_value(x, exp) for x in rgb])
 
-def saturate_value(x):
-    return 127.5 + sign(x - 127.5) * 127.5 * math.sqrt(abs(x - 127.5) / 127.5)
+def saturate_value(x, exp):
+    return 127.5 + sign(x - 127.5) * 127.5 * pow(abs(x - 127.5) / 127.5, exp)
 
 def test():
     size = 512
@@ -118,6 +118,7 @@
     input_filename, output_filename = sys.argv[1:3]
     rotate = "-r" in sys.argv[3:]
     saturate = "-s" in sys.argv[3:]
+    desaturate = "-d" in sys.argv[3:]
 
     x = EXIF.process_file(open(input_filename))
     im = PIL.Image.open(input_filename)
@@ -131,8 +132,8 @@
         c = {}
         for x in range(0, width):
             rgb = im.getpixel((x, y))
-            if saturate:
-                rgb = saturate(rgb)
+            if saturate or desaturate:
+                rgb = saturate_rgb(rgb, saturate and 0.5 or 2)
             value = get_value((x, y), rgb, width, height)
             im.putpixel((x, y), value)
             if not c.has_key(value):