# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1441716125 -7200
# Node ID 19ad565c6647cefe95712ee585c9848711e81b86

A palette optimiser tool converting images to primary and secondary colours.

diff -r 000000000000 -r 19ad565c6647 optimiser.py
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/optimiser.py	Tue Sep 08 14:42:05 2015 +0200
@@ -0,0 +1,52 @@
+#!/usr/bin/env python
+
+from array import array
+import PIL.Image
+import sys
+
+def scale(v):
+    return (v + 64) / 128
+
+def point(rgb):
+    return tuple(map(scale, rgb))
+
+def index(p):
+    return p[0] * 9 + p[1] * 3 + p[2]
+
+def colour(i):
+    return (255 * (i % 2), 255 * ((i / 2) % 2), 255 * ((i / 4) % 2))
+
+tones = [
+    "__", "B_", "BB", # 00x
+    "G_", "C_", "CB", # 01x
+    "GG", "CG", "CC", # 02x
+    "R_", "M_", "MB", # 10x
+    "Y_", "W_", "WB", # 11x
+    "YG", "WG", "WC", # 12x
+    "RR", "MR", "MM", # 20x
+    "YR", "WR", "WM", # 21x
+    "YY", "WY", "WW", # 22x
+    ]
+
+colours = ["_", "R", "G", "Y", "B", "M", "C", "W"]
+
+if __name__ == "__main__":
+
+    input_filename, output_filename = sys.argv[1:3]
+
+    im = PIL.Image.open(input_filename)
+    im = im.resize((320, 256))
+
+    for row in range(0, 256):
+        for column in range(0, 320):
+            rgb = im.getpixel((column, row))
+            p = point(rgb)
+            i = index(p)
+            t = tones[i]
+            c = t[row % 2]
+            i = colours.index(c)
+            im.putpixel((column, row), colour(i))
+
+    im.save(output_filename)
+
+# vim: tabstop=4 expandtab shiftwidth=4