# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443883937 -7200
# Node ID 9060af8f5ef50aa1c76dc398594f0b3353a1e1d1
# Parent  da4132364cfd8e838b5020c2a0f04375d87813ec
Adopt a more thorough model of colour selection.

diff -r da4132364cfd -r 9060af8f5ef5 optimiser.py
--- a/optimiser.py	Sat Oct 03 01:32:26 2015 +0200
+++ b/optimiser.py	Sat Oct 03 16:52:17 2015 +0200
@@ -18,26 +18,68 @@
     r2, g2, b2 = rgb2
     return math.sqrt(pow(r1 - r2, 2) + pow(g1 - g2, 2) + pow(b1 - b2, 2))
 
-def distribution(rgb, values=None):
-    l = []
-    total = 0
-    for c in values or corners:
-        d = distance(rgb, c)
-        if d == 0:
-            return [(1, c)]
-        l.append((pow(d, -3), c))
-        total += pow(d, -3)
-    return [(d / total, c) for d, c in l]
+def nearest(rgb, values):
+    l = [(distance(rgb, value), value) for value in values]
+    l.sort()
+    return l[0][1]
+
+def scale(rgb):
+    return tuple(map(lambda x: x / 255.0, rgb))
+
+def invert(srgb):
+    return tuple(map(lambda x: 1.0 - x, srgb))
+
+def combination(rgb):
+    rgb = 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 d
 
-def pattern(rgb, values=None):
-    l = distribution(rgb, values or corners)
+def combine(d):
+    out = [0, 0, 0]
+    for v, rgb in d:
+        out[0] += v * rgb[0]
+        out[1] += v * rgb[1]
+        out[2] += v * rgb[2]
+    return out
+
+"""
+r(R - K)
+r(Y - G)
+r(M - B)
+r(W - C)
+g(G - K)
+g(Y - R)
+g(C - B)
+g(W - M)
+b(B - K)
+b(M - R)
+b(C - G)
+b(W - Y)
+
+b(g(r(W - C) - r(M - B)) - g(r(Y - G) - r(R - K)))
+b(r(g(W - M) - g(C - B)) - r(g(Y - R) - g(G - K)))
+
+b(g(rW + riC) + gi(rM + riB)) + bi(g(rY + riG) + gi(rR + riK))
+b(r(gW + giM) + ri(gC + giB)) + bi(r(gY + giR) + ri(gG + giK))
+
+W(b.g.r) + C(b.g.ri) + M(b.gi.r) + B(b.g.ri) + Y(bi.g.r) + G(bi.g.ri) + R(bi.gi.r) + K(bi.gi.ri)
+...
+"""
+
+def pattern(rgb):
+    l = combination(rgb)
     l.sort(reverse=True)
     return l
 
-def get_value(rgb, values=None):
+def get_value(rgb):
     choose = random()
     threshold = 0
-    for f, c in pattern(rgb, values):
+    for f, c in pattern(rgb):
         threshold += f
         if choose < threshold:
             return c
@@ -128,7 +170,7 @@
 
             # Sum the colour probabilities.
 
-            for f, value in distribution(rgb):
+            for f, value in combination(rgb):
                 if not c.has_key(value):
                     c[value] = f
                 else:
@@ -142,11 +184,11 @@
         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)
+        #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))
@@ -156,8 +198,7 @@
 
             value = get_value(rgb)
             if value in least:
-                rgb = im.getpixel((x, y))
-                value = get_value(value, most)
+                value = nearest(value, most)
 
             im.putpixel((x, y), value)