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authorFredrik Lundh <fredrik@pythonware.com>2005-11-12 15:21:05 (GMT)
committerFredrik Lundh <fredrik@pythonware.com>2005-11-12 15:21:05 (GMT)
commit0d89e351e1c8347e592e68a6c3c3825fd19fb749 (patch)
treea0a0b521c1687fbe8ff577dae6f45b591a88c46c /Lib/colorsys.py
parent3a49e92d7dd7154a1f382ca1b28ffe610295147f (diff)
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r879@spiff: Fredrik | 2005-11-12 14:38:03 +0100
r878@spiff: Fredrik | 2005-11-12 14:37:22 +0100 minor docstring and comment tweaks (wikipedia might not be the ultimate reference, but it's a lot better than "XXX" ;-)
Diffstat (limited to 'Lib/colorsys.py')
-rw-r--r--Lib/colorsys.py25
1 files changed, 14 insertions, 11 deletions
diff --git a/Lib/colorsys.py b/Lib/colorsys.py
index c2cdf57..39b4b16 100644
--- a/Lib/colorsys.py
+++ b/Lib/colorsys.py
@@ -5,17 +5,21 @@ 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].
-Inputs outside this range may cause exceptions or invalid outputs.
+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: used by composite video signals
+YIQ: Luminance, Chrominance (used by composite video signals)
HLS: Hue, Luminance, Saturation
HSV: Hue, Saturation, Value
"""
+
# References:
-# XXX Where's the literature?
+# 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"]
@@ -26,7 +30,6 @@ 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
@@ -50,10 +53,10 @@ def yiq_to_rgb(y, i, q):
return (r, g, b)
-# HLS: Hue, Luminance, S???
+# HLS: Hue, Luminance, Saturation
# H: position in the spectrum
-# L: ???
-# S: ???
+# L: color lightness
+# S: color saturation
def rgb_to_hls(r, g, b):
maxc = max(r, g, b)
@@ -87,10 +90,10 @@ def _v(m1, m2, hue):
return m1
-# HSV: Hue, Saturation, Value(?)
+# HSV: Hue, Saturation, Value
# H: position in the spectrum
-# S: ???
-# V: ???
+# S: color saturation ("purity")
+# V: color brightness
def rgb_to_hsv(r, g, b):
maxc = max(r, g, b)