/usr/lib/python3.7/colorsys.py is in libpython3.7-stdlib 3.7.0~b3-1.
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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 | """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)
# XXX Can optimize (maxc+minc) and (maxc-minc)
l = (minc+maxc)/2.0
if minc == maxc:
return 0.0, l, 0.0
if l <= 0.5:
s = (maxc-minc) / (maxc+minc)
else:
s = (maxc-minc) / (2.0-maxc-minc)
rc = (maxc-r) / (maxc-minc)
gc = (maxc-g) / (maxc-minc)
bc = (maxc-b) / (maxc-minc)
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)
v = maxc
if minc == maxc:
return 0.0, 0.0, v
s = (maxc-minc) / maxc
rc = (maxc-r) / (maxc-minc)
gc = (maxc-g) / (maxc-minc)
bc = (maxc-b) / (maxc-minc)
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
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