# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1444428354 -7200
# Node ID 92c6d7aa93436ea007001133246f440b2e1dc3e4
# Parent  ba632fd74cbb14d16f59105e1cce956998300f1d
Used more explicit coding practices to help Shedskin.

diff -r ba632fd74cbb -r 92c6d7aa9343 optimiser.py
--- a/optimiser.py	Fri Oct 09 23:48:21 2015 +0200
+++ b/optimiser.py	Sat Oct 10 00:05:54 2015 +0200
@@ -44,13 +44,16 @@
     return math.sqrt(pow(r1 - r2, 2) + pow(g1 - g2, 2) + pow(b1 - b2, 2))
 
 def restore(srgb):
-    return tuple(map(lambda x: int(x * 255.0), srgb))
+    r, g, b = srgb
+    return int(r * 255.0), int(g * 255.0), int(b * 255.0)
 
 def scale(rgb):
-    return tuple(map(lambda x: x / 255.0, rgb))
+    r, g, b = rgb
+    return r / 255.0, g / 255.0, b / 255.0
 
 def invert(srgb):
-    return tuple(map(lambda x: 1.0 - x, srgb))
+    r, g, b = srgb
+    return 1.0 - r, 1.0 - g, 1.0 - b
 
 # Colour distribution functions.
 
@@ -96,12 +99,18 @@
     and replacing their common contributions with black and white contributions.
     """
 
-    d = dict([(value, f) for f, value in d])
-    for primary, secondary in map(complements, [(0, 0, 0), (255, 0, 0), (0, 255, 0), (0, 0, 255)]):
-        common = min(d[primary], d[secondary])
-        d[primary] -= common
-        d[secondary] -= common
-    return [(f, value) for value, f in d.items()]
+    dd = {}
+    for f, value in d:
+        dd[value] = f
+    for colour in [(0, 0, 0), (255, 0, 0), (0, 255, 0), (0, 0, 255)]:
+        primary, secondary = complements(colour)
+        common = min(dd[primary], dd[secondary])
+        dd[primary] -= common
+        dd[secondary] -= common
+    d = []
+    for value, f in dd.items():
+        d.append((f, value))
+    return d
 
 def combine(d):
 
@@ -121,7 +130,10 @@
     specified 'chosen' colours.
     """
 
-    l = [(f, value) for f, value in combination(rgb) if not chosen or value in chosen]
+    l = []
+    for f, value in combination(rgb):
+        if not chosen or value in chosen:
+            l.append((f, value))
     l.sort(reverse=True)
     return l
 
@@ -155,13 +167,15 @@
     return x >= 0 and 1 or -1
 
 def saturate_rgb(rgb, exp):
-    return tuple([saturate_value(x, exp) for x in rgb])
+    r, g, b = rgb
+    return saturate_value(r, exp), saturate_value(g, exp), saturate_value(b, exp)
 
 def saturate_value(x, exp):
     return int(127.5 + sign(x - 127.5) * 127.5 * pow(abs(x - 127.5) / 127.5, exp))
 
 def amplify_rgb(rgb, exp):
-    return tuple([amplify_value(x, exp) for x in rgb])
+    r, g, b = rgb
+    return amplify_value(r, exp), amplify_value(g, exp), amplify_value(b, exp)
 
 def amplify_value(x, exp):
     return int(pow(x / 255.0, exp) * 255.0)
@@ -185,9 +199,11 @@
             else:
                 c[value] += f
 
-    c = [(n/width, value) for value, n in c.items()]
-    c.sort(reverse=True)
-    return c
+    d = []
+    for value, n in c.items():
+        d.append((n/width, value))
+    d.sort(reverse=True)
+    return d
 
 def get_combinations(c, n):
 
@@ -203,7 +219,10 @@
             total += f
         all.append((total, l))
     all.sort(reverse=True)
-    return [l for total, l in all]
+    cc = []
+    for total, l in all:
+        cc.append(l)
+    return cc
 
 def test_slice(im, size, r):
     for g in range(0, size):
@@ -298,12 +317,20 @@
 
             if x < width - 1:
                 rgbn = im.getpixel((x+1, y))
-                rgbn = tuple(map(lambda i: clip(i[0] + (i[1] - i[2]) / 4.0), zip(rgbn, rgb, value)))
+                rgbn = (
+                    clip(rgbn[0] + (rgb[0] - value[0]) / 4.0),
+                    clip(rgbn[1] + (rgb[1] - value[1]) / 4.0),
+                    clip(rgbn[2] + (rgb[2] - value[2]) / 4.0)
+                    )
                 im.putpixel((x+1, y), rgbn)
 
             if y < height - 1:
                 rgbn = im.getpixel((x, y+1))
-                rgbn = tuple(map(lambda i: clip(i[0] + (i[1] - i[2]) / 2.0), zip(rgbn, rgb, value)))
+                rgbn = (
+                    clip(rgbn[0] + (rgb[0] - value[0]) / 2.0),
+                    clip(rgbn[1] + (rgb[1] - value[1]) / 2.0),
+                    clip(rgbn[2] + (rgb[2] - value[2]) / 2.0)
+                    )
                 im.putpixel((x, y+1), rgbn)
 
 class SimpleImage: