Initial revision

diff --git a/Demo/sgi/video/colorsys.py b/Demo/sgi/video/colorsys.py
new file mode 100755 (executable)
index 0000000..872b533
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+++ b/Demo/sgi/video/colorsys.py
@@ -0,0 +1,20 @@
+#
+# Module color - do color conversions
+#
+
+def rgb_to_yiq(r,g,b):
+    y = 0.30*r + 0.59*g + 0.11*b
+    i = 0.60*r - 0.28*g - 0.32*b
+    q = 0.21*r - 0.52*g + 0.31*b
+    return (y,i,q)
+def yiq_to_rgb(y,i,q):
+    r = y + 0.948262*i + 0.624013*q
+    g = y - 0.276066*i - 0.639810*q
+    b = y - 1.105450*i + 1.729860*q
+    if r < 0.0: r = 0.0
+    if g < 0.0: g = 0.0
+    if b < 0.0: b = 0.0
+    if r > 1.0: r = 1.0
+    if g > 1.0: g = 1.0
+    if b > 1.0: b = 1.0
+    return (r,g,b)