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v0.5.1
v0.5.1
https://github.com/python/cpython
Revision b6987b13fecdfbbc3a45e84025754d06ad18fca9 authored by Guido van Rossum on 07 April 1999, 18:32:51 UTC, committed by Guido van Rossum on 07 April 1999, 18:32:51 UTC
before exiting when an error happened. This didn't work right when Python is invoked from a daemon.
1 parent a99c5db
Tip revision: b6987b13fecdfbbc3a45e84025754d06ad18fca9 authored by Guido van Rossum on 07 April 1999, 18:32:51 UTC
Alas, get rid of the Win specific hack to ask the user to press Return
Alas, get rid of the Win specific hack to ask the user to press Return
Tip revision: b6987b1
colorsys.py
"""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].
Inputs outside this range may cause exceptions or invalid outputs.
Supported color systems:
RGB: Red, Green, Blue components
YIQ: used by composite video signals
HLS: Hue, Luminance, S???
HSV: Hue, Saturation, Value(?)
"""
# References:
# XXX Where's the literature?
# 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
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)
# HLS: Hue, Luminance, S???
# H: position in the spectrum
# L: ???
# S: ???
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: ???
# V: ???
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))
if i%6 == 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
![swh spinner](/static/img/swh-spinner.gif)
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