# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1443892091 -7200
# Node ID baa08ae98f2e88bd6a5d30e5980b768a0b0b5bb3
# Parent  9060af8f5ef50aa1c76dc398594f0b3353a1e1d1
Added a "balancing" function to remove primary/secondary complement pairs, thus
removing colour noise and simplifying the job of the optimisation routine.
Added the useful preview function back to the program.
Removed some working notes.

diff -r 9060af8f5ef5 -r baa08ae98f2e optimiser.py
--- a/optimiser.py	Sat Oct 03 16:52:17 2015 +0200
+++ b/optimiser.py	Sat Oct 03 19:08:11 2015 +0200
@@ -23,6 +23,9 @@
     l.sort()
     return l[0][1]
 
+def restore(srgb):
+    return tuple(map(lambda x: int(x * 255.0), srgb))
+
 def scale(rgb):
     return tuple(map(lambda x: x / 255.0, rgb))
 
@@ -37,7 +40,21 @@
     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
+    return balance(d)
+
+def complements(rgb):
+    r, g, b = rgb
+    return rgb, restore(invert(scale(rgb)))
+
+def balance(d):
+    d = dict([(value, f) for f, value in d])
+    for primary, secondary in map(complements, [(255, 0, 0), (0, 255, 0), (0, 0, 255)]):
+        common = min(d[primary], d[secondary])
+        d[primary] -= common
+        d[secondary] -= common
+        d[(0, 0, 0)] += common
+        d[(255, 255, 255)] += common
+    return [(f, value) for value, f in d.items()]
 
 def combine(d):
     out = [0, 0, 0]
@@ -47,30 +64,6 @@
         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)
@@ -144,10 +137,12 @@
 
     input_filename, output_filename = sys.argv[1:3]
     basename, ext = splitext(output_filename)
+    preview_filename = "".join([basename + "_preview", ext])
 
     rotate = "-r" in sys.argv[3:]
     saturate = sys.argv[3:].count("-s")
     desaturate = sys.argv[3:].count("-d")
+    preview = "-p" in sys.argv[3:]
 
     x = EXIF.process_file(open(input_filename))
     im = PIL.Image.open(input_filename).convert("RGB")
@@ -180,6 +175,15 @@
         c.sort(reverse=True)
         colours.append(c)
 
+    if preview:
+        imp = im.copy()
+        for y in range(0, height):
+            for x in range(0, width):
+                rgb = imp.getpixel((x, y))
+                value = get_value(rgb)
+                imp.putpixel((x, y), value)
+        imp.save(preview_filename)
+
     for y, c in enumerate(colours):
         most = [value for n, value in c[:4]]
         least = [value for n, value in c[4:]]