# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443713678 -7200
# Node ID 5d600ea41889b3f49afd601fc5588e43e683883f
# Parent  c768f24e5233faecb78a5fa97f1759bed9c2baac
Experiment with calculating the dithering factor using the sum of the lengths of
the vectors connecting the start colour to the end colour via the given colour.

diff -r c768f24e5233 -r 5d600ea41889 optimiser.py
--- a/optimiser.py	Thu Oct 01 12:50:55 2015 +0200
+++ b/optimiser.py	Thu Oct 01 17:34:38 2015 +0200
@@ -21,13 +21,7 @@
     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)
+    return distance(start, rgb) / (distance(start, rgb) + distance(rgb, end))
 
 def darklight(rgb1, rgb2):
     if brightness(rgb1) <= brightness(rgb2):