diff --git a/python-stdlib/colorsys/colorsys.py b/python-stdlib/colorsys/colorsys.py
new file mode 100644
index 000000000..9bdc83e37
--- /dev/null
+++ b/python-stdlib/colorsys/colorsys.py
@@ -0,0 +1,166 @@
+"""Conversion functions between RGB and other color systems.
+
+This modules provides two functions for each color system ABC:
+
+ rgb_to_abc(r, g, b) --> a, b, c
+ abc_to_rgb(a, b, c) --> r, g, b
+
+All inputs and outputs are triples of floats in the range [0.0...1.0]
+(with the exception of I and Q, which covers a slightly larger range).
+Inputs outside the valid range may cause exceptions or invalid outputs.
+
+Supported color systems:
+RGB: Red, Green, Blue components
+YIQ: Luminance, Chrominance (used by composite video signals)
+HLS: Hue, Luminance, Saturation
+HSV: Hue, Saturation, Value
+"""
+
+# References:
+# http://en.wikipedia.org/wiki/YIQ
+# http://en.wikipedia.org/wiki/HLS_color_space
+# http://en.wikipedia.org/wiki/HSV_color_space
+
+__all__ = ["rgb_to_yiq","yiq_to_rgb","rgb_to_hls","hls_to_rgb",
+ "rgb_to_hsv","hsv_to_rgb"]
+
+# Some floating point constants
+
+ONE_THIRD = 1.0/3.0
+ONE_SIXTH = 1.0/6.0
+TWO_THIRD = 2.0/3.0
+
+# YIQ: used by composite video signals (linear combinations of RGB)
+# Y: perceived grey level (0.0 == black, 1.0 == white)
+# I, Q: color components
+#
+# There are a great many versions of the constants used in these formulae.
+# The ones in this library uses constants from the FCC version of NTSC.
+
+def rgb_to_yiq(r, g, b):
+ y = 0.30*r + 0.59*g + 0.11*b
+ i = 0.74*(r-y) - 0.27*(b-y)
+ q = 0.48*(r-y) + 0.41*(b-y)
+ return (y, i, q)
+
+def yiq_to_rgb(y, i, q):
+ # r = y + (0.27*q + 0.41*i) / (0.74*0.41 + 0.27*0.48)
+ # b = y + (0.74*q - 0.48*i) / (0.74*0.41 + 0.27*0.48)
+ # g = y - (0.30*(r-y) + 0.11*(b-y)) / 0.59
+
+ r = y + 0.9468822170900693*i + 0.6235565819861433*q
+ g = y - 0.27478764629897834*i - 0.6356910791873801*q
+ b = y - 1.1085450346420322*i + 1.7090069284064666*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)
+
+
+# HLS: Hue, Luminance, Saturation
+# H: position in the spectrum
+# L: color lightness
+# S: color saturation
+
+def rgb_to_hls(r, g, b):
+ maxc = max(r, g, b)
+ minc = min(r, g, b)
+ sumc = (maxc+minc)
+ rangec = (maxc-minc)
+ l = sumc/2.0
+ if minc == maxc:
+ return 0.0, l, 0.0
+ if l <= 0.5:
+ s = rangec / sumc
+ else:
+ s = rangec / (2.0-sumc)
+ rc = (maxc-r) / rangec
+ gc = (maxc-g) / rangec
+ bc = (maxc-b) / rangec
+ if r == maxc:
+ h = bc-gc
+ elif g == maxc:
+ h = 2.0+rc-bc
+ else:
+ h = 4.0+gc-rc
+ h = (h/6.0) % 1.0
+ return h, l, s
+
+def hls_to_rgb(h, l, s):
+ if s == 0.0:
+ return l, l, l
+ if l <= 0.5:
+ m2 = l * (1.0+s)
+ else:
+ m2 = l+s-(l*s)
+ m1 = 2.0*l - m2
+ return (_v(m1, m2, h+ONE_THIRD), _v(m1, m2, h), _v(m1, m2, h-ONE_THIRD))
+
+def _v(m1, m2, hue):
+ hue = hue % 1.0
+ if hue < ONE_SIXTH:
+ return m1 + (m2-m1)*hue*6.0
+ if hue < 0.5:
+ return m2
+ if hue < TWO_THIRD:
+ return m1 + (m2-m1)*(TWO_THIRD-hue)*6.0
+ return m1
+
+
+# HSV: Hue, Saturation, Value
+# H: position in the spectrum
+# S: color saturation ("purity")
+# V: color brightness
+
+def rgb_to_hsv(r, g, b):
+ maxc = max(r, g, b)
+ minc = min(r, g, b)
+ rangec = (maxc-minc)
+ v = maxc
+ if minc == maxc:
+ return 0.0, 0.0, v
+ s = rangec / maxc
+ rc = (maxc-r) / rangec
+ gc = (maxc-g) / rangec
+ bc = (maxc-b) / rangec
+ if r == maxc:
+ h = bc-gc
+ elif g == maxc:
+ h = 2.0+rc-bc
+ else:
+ h = 4.0+gc-rc
+ h = (h/6.0) % 1.0
+ return h, s, v
+
+def hsv_to_rgb(h, s, v):
+ if s == 0.0:
+ return v, v, v
+ i = int(h*6.0) # XXX assume int() truncates!
+ f = (h*6.0) - i
+ p = v*(1.0 - s)
+ q = v*(1.0 - s*f)
+ t = v*(1.0 - s*(1.0-f))
+ i = i%6
+ if i == 0:
+ return v, t, p
+ if i == 1:
+ return q, v, p
+ if i == 2:
+ return p, v, t
+ if i == 3:
+ return p, q, v
+ if i == 4:
+ return t, p, v
+ if i == 5:
+ return v, p, q
+ # Cannot get here
diff --git a/python-stdlib/colorsys/test_colorsys.py b/python-stdlib/colorsys/test_colorsys.py
new file mode 100644
index 000000000..a41eec349
--- /dev/null
+++ b/python-stdlib/colorsys/test_colorsys.py
@@ -0,0 +1,100 @@
+import unittest
+import colorsys
+
+def frange(start, stop, step):
+ while start <= stop:
+ yield start
+ start += step
+
+class ColorsysTest(unittest.TestCase):
+
+ def assertTripleEqual(self, tr1, tr2):
+ self.assertEqual(len(tr1), 3)
+ self.assertEqual(len(tr2), 3)
+ self.assertAlmostEqual(tr1[0], tr2[0])
+ self.assertAlmostEqual(tr1[1], tr2[1])
+ self.assertAlmostEqual(tr1[2], tr2[2])
+
+ def test_hsv_roundtrip(self):
+ for r in frange(0.0, 1.0, 0.2):
+ for g in frange(0.0, 1.0, 0.2):
+ for b in frange(0.0, 1.0, 0.2):
+ rgb = (r, g, b)
+ self.assertTripleEqual(
+ rgb,
+ colorsys.hsv_to_rgb(*colorsys.rgb_to_hsv(*rgb))
+ )
+
+ def test_hsv_values(self):
+ values = [
+ # rgb, hsv
+ ((0.0, 0.0, 0.0), ( 0 , 0.0, 0.0)), # black
+ ((0.0, 0.0, 1.0), (4./6., 1.0, 1.0)), # blue
+ ((0.0, 1.0, 0.0), (2./6., 1.0, 1.0)), # green
+ ((0.0, 1.0, 1.0), (3./6., 1.0, 1.0)), # cyan
+ ((1.0, 0.0, 0.0), ( 0 , 1.0, 1.0)), # red
+ ((1.0, 0.0, 1.0), (5./6., 1.0, 1.0)), # purple
+ ((1.0, 1.0, 0.0), (1./6., 1.0, 1.0)), # yellow
+ ((1.0, 1.0, 1.0), ( 0 , 0.0, 1.0)), # white
+ ((0.5, 0.5, 0.5), ( 0 , 0.0, 0.5)), # grey
+ ]
+ for (rgb, hsv) in values:
+ self.assertTripleEqual(hsv, colorsys.rgb_to_hsv(*rgb))
+ self.assertTripleEqual(rgb, colorsys.hsv_to_rgb(*hsv))
+
+ def test_hls_roundtrip(self):
+ for r in frange(0.0, 1.0, 0.2):
+ for g in frange(0.0, 1.0, 0.2):
+ for b in frange(0.0, 1.0, 0.2):
+ rgb = (r, g, b)
+ self.assertTripleEqual(
+ rgb,
+ colorsys.hls_to_rgb(*colorsys.rgb_to_hls(*rgb))
+ )
+
+ def test_hls_values(self):
+ values = [
+ # rgb, hls
+ ((0.0, 0.0, 0.0), ( 0 , 0.0, 0.0)), # black
+ ((0.0, 0.0, 1.0), (4./6., 0.5, 1.0)), # blue
+ ((0.0, 1.0, 0.0), (2./6., 0.5, 1.0)), # green
+ ((0.0, 1.0, 1.0), (3./6., 0.5, 1.0)), # cyan
+ ((1.0, 0.0, 0.0), ( 0 , 0.5, 1.0)), # red
+ ((1.0, 0.0, 1.0), (5./6., 0.5, 1.0)), # purple
+ ((1.0, 1.0, 0.0), (1./6., 0.5, 1.0)), # yellow
+ ((1.0, 1.0, 1.0), ( 0 , 1.0, 0.0)), # white
+ ((0.5, 0.5, 0.5), ( 0 , 0.5, 0.0)), # grey
+ ]
+ for (rgb, hls) in values:
+ self.assertTripleEqual(hls, colorsys.rgb_to_hls(*rgb))
+ self.assertTripleEqual(rgb, colorsys.hls_to_rgb(*hls))
+
+ def test_yiq_roundtrip(self):
+ for r in frange(0.0, 1.0, 0.2):
+ for g in frange(0.0, 1.0, 0.2):
+ for b in frange(0.0, 1.0, 0.2):
+ rgb = (r, g, b)
+ self.assertTripleEqual(
+ rgb,
+ colorsys.yiq_to_rgb(*colorsys.rgb_to_yiq(*rgb))
+ )
+
+ def test_yiq_values(self):
+ values = [
+ # rgb, yiq
+ ((0.0, 0.0, 0.0), (0.0, 0.0, 0.0)), # black
+ ((0.0, 0.0, 1.0), (0.11, -0.3217, 0.3121)), # blue
+ ((0.0, 1.0, 0.0), (0.59, -0.2773, -0.5251)), # green
+ ((0.0, 1.0, 1.0), (0.7, -0.599, -0.213)), # cyan
+ ((1.0, 0.0, 0.0), (0.3, 0.599, 0.213)), # red
+ ((1.0, 0.0, 1.0), (0.41, 0.2773, 0.5251)), # purple
+ ((1.0, 1.0, 0.0), (0.89, 0.3217, -0.3121)), # yellow
+ ((1.0, 1.0, 1.0), (1.0, 0.0, 0.0)), # white
+ ((0.5, 0.5, 0.5), (0.5, 0.0, 0.0)), # grey
+ ]
+ for (rgb, yiq) in values:
+ self.assertTripleEqual(yiq, colorsys.rgb_to_yiq(*rgb))
+ self.assertTripleEqual(rgb, colorsys.yiq_to_rgb(*yiq))
+
+if __name__ == "__main__":
+ unittest.main()
\ No newline at end of file
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