kopia lustrzana https://github.com/micropython/micropython-lib
Added colorsys and test_colorsys from CPython
Matt Trentini
rodzic
3c383f6d28
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2edadaeb54
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"""Conversion functions between RGB and other color systems.
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This modules provides two functions for each color system ABC:
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rgb_to_abc(r, g, b) --> a, b, c
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abc_to_rgb(a, b, c) --> r, g, b
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All inputs and outputs are triples of floats in the range [0.0...1.0]
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(with the exception of I and Q, which covers a slightly larger range).
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Inputs outside the valid range may cause exceptions or invalid outputs.
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Supported color systems:
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RGB: Red, Green, Blue components
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YIQ: Luminance, Chrominance (used by composite video signals)
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HLS: Hue, Luminance, Saturation
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HSV: Hue, Saturation, Value
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"""
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# References:
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# http://en.wikipedia.org/wiki/YIQ
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# http://en.wikipedia.org/wiki/HLS_color_space
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# http://en.wikipedia.org/wiki/HSV_color_space
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__all__ = ["rgb_to_yiq","yiq_to_rgb","rgb_to_hls","hls_to_rgb",
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"rgb_to_hsv","hsv_to_rgb"]
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# Some floating point constants
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ONE_THIRD = 1.0/3.0
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ONE_SIXTH = 1.0/6.0
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TWO_THIRD = 2.0/3.0
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# YIQ: used by composite video signals (linear combinations of RGB)
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# Y: perceived grey level (0.0 == black, 1.0 == white)
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# I, Q: color components
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#
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# There are a great many versions of the constants used in these formulae.
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# The ones in this library uses constants from the FCC version of NTSC.
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def rgb_to_yiq(r, g, b):
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y = 0.30*r + 0.59*g + 0.11*b
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i = 0.74*(r-y) - 0.27*(b-y)
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q = 0.48*(r-y) + 0.41*(b-y)
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return (y, i, q)
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def yiq_to_rgb(y, i, q):
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# r = y + (0.27*q + 0.41*i) / (0.74*0.41 + 0.27*0.48)
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# b = y + (0.74*q - 0.48*i) / (0.74*0.41 + 0.27*0.48)
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# g = y - (0.30*(r-y) + 0.11*(b-y)) / 0.59
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r = y + 0.9468822170900693*i + 0.6235565819861433*q
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g = y - 0.27478764629897834*i - 0.6356910791873801*q
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b = y - 1.1085450346420322*i + 1.7090069284064666*q
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if r < 0.0:
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r = 0.0
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if g < 0.0:
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g = 0.0
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if b < 0.0:
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b = 0.0
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if r > 1.0:
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r = 1.0
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if g > 1.0:
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g = 1.0
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if b > 1.0:
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b = 1.0
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return (r, g, b)
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# HLS: Hue, Luminance, Saturation
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# H: position in the spectrum
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# L: color lightness
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# S: color saturation
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def rgb_to_hls(r, g, b):
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maxc = max(r, g, b)
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minc = min(r, g, b)
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sumc = (maxc+minc)
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rangec = (maxc-minc)
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l = sumc/2.0
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if minc == maxc:
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return 0.0, l, 0.0
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if l <= 0.5:
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s = rangec / sumc
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else:
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s = rangec / (2.0-sumc)
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rc = (maxc-r) / rangec
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gc = (maxc-g) / rangec
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bc = (maxc-b) / rangec
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if r == maxc:
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h = bc-gc
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elif g == maxc:
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h = 2.0+rc-bc
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else:
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h = 4.0+gc-rc
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h = (h/6.0) % 1.0
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return h, l, s
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def hls_to_rgb(h, l, s):
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if s == 0.0:
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return l, l, l
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if l <= 0.5:
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m2 = l * (1.0+s)
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else:
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m2 = l+s-(l*s)
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m1 = 2.0*l - m2
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return (_v(m1, m2, h+ONE_THIRD), _v(m1, m2, h), _v(m1, m2, h-ONE_THIRD))
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def _v(m1, m2, hue):
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hue = hue % 1.0
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if hue < ONE_SIXTH:
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return m1 + (m2-m1)*hue*6.0
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if hue < 0.5:
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return m2
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if hue < TWO_THIRD:
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return m1 + (m2-m1)*(TWO_THIRD-hue)*6.0
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return m1
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# HSV: Hue, Saturation, Value
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# H: position in the spectrum
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# S: color saturation ("purity")
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# V: color brightness
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def rgb_to_hsv(r, g, b):
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maxc = max(r, g, b)
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minc = min(r, g, b)
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rangec = (maxc-minc)
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v = maxc
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if minc == maxc:
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return 0.0, 0.0, v
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s = rangec / maxc
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rc = (maxc-r) / rangec
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gc = (maxc-g) / rangec
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bc = (maxc-b) / rangec
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if r == maxc:
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h = bc-gc
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elif g == maxc:
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h = 2.0+rc-bc
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else:
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h = 4.0+gc-rc
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h = (h/6.0) % 1.0
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return h, s, v
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def hsv_to_rgb(h, s, v):
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if s == 0.0:
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return v, v, v
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i = int(h*6.0) # XXX assume int() truncates!
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f = (h*6.0) - i
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p = v*(1.0 - s)
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q = v*(1.0 - s*f)
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t = v*(1.0 - s*(1.0-f))
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i = i%6
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if i == 0:
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return v, t, p
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if i == 1:
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return q, v, p
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if i == 2:
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return p, v, t
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if i == 3:
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return p, q, v
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if i == 4:
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return t, p, v
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if i == 5:
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return v, p, q
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# Cannot get here
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@ -0,0 +1,100 @@
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import unittest
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import colorsys
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def frange(start, stop, step):
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while start <= stop:
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yield start
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start += step
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class ColorsysTest(unittest.TestCase):
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def assertTripleEqual(self, tr1, tr2):
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self.assertEqual(len(tr1), 3)
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self.assertEqual(len(tr2), 3)
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self.assertAlmostEqual(tr1[0], tr2[0])
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self.assertAlmostEqual(tr1[1], tr2[1])
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self.assertAlmostEqual(tr1[2], tr2[2])
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def test_hsv_roundtrip(self):
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for r in frange(0.0, 1.0, 0.2):
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for g in frange(0.0, 1.0, 0.2):
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for b in frange(0.0, 1.0, 0.2):
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rgb = (r, g, b)
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self.assertTripleEqual(
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rgb,
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colorsys.hsv_to_rgb(*colorsys.rgb_to_hsv(*rgb))
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)
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def test_hsv_values(self):
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values = [
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# rgb, hsv
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((0.0, 0.0, 0.0), ( 0 , 0.0, 0.0)), # black
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((0.0, 0.0, 1.0), (4./6., 1.0, 1.0)), # blue
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((0.0, 1.0, 0.0), (2./6., 1.0, 1.0)), # green
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((0.0, 1.0, 1.0), (3./6., 1.0, 1.0)), # cyan
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((1.0, 0.0, 0.0), ( 0 , 1.0, 1.0)), # red
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((1.0, 0.0, 1.0), (5./6., 1.0, 1.0)), # purple
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((1.0, 1.0, 0.0), (1./6., 1.0, 1.0)), # yellow
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((1.0, 1.0, 1.0), ( 0 , 0.0, 1.0)), # white
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((0.5, 0.5, 0.5), ( 0 , 0.0, 0.5)), # grey
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]
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for (rgb, hsv) in values:
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self.assertTripleEqual(hsv, colorsys.rgb_to_hsv(*rgb))
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self.assertTripleEqual(rgb, colorsys.hsv_to_rgb(*hsv))
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def test_hls_roundtrip(self):
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for r in frange(0.0, 1.0, 0.2):
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for g in frange(0.0, 1.0, 0.2):
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for b in frange(0.0, 1.0, 0.2):
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rgb = (r, g, b)
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self.assertTripleEqual(
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rgb,
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colorsys.hls_to_rgb(*colorsys.rgb_to_hls(*rgb))
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)
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def test_hls_values(self):
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values = [
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# rgb, hls
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((0.0, 0.0, 0.0), ( 0 , 0.0, 0.0)), # black
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((0.0, 0.0, 1.0), (4./6., 0.5, 1.0)), # blue
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((0.0, 1.0, 0.0), (2./6., 0.5, 1.0)), # green
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((0.0, 1.0, 1.0), (3./6., 0.5, 1.0)), # cyan
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((1.0, 0.0, 0.0), ( 0 , 0.5, 1.0)), # red
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((1.0, 0.0, 1.0), (5./6., 0.5, 1.0)), # purple
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((1.0, 1.0, 0.0), (1./6., 0.5, 1.0)), # yellow
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((1.0, 1.0, 1.0), ( 0 , 1.0, 0.0)), # white
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((0.5, 0.5, 0.5), ( 0 , 0.5, 0.0)), # grey
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]
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for (rgb, hls) in values:
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self.assertTripleEqual(hls, colorsys.rgb_to_hls(*rgb))
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self.assertTripleEqual(rgb, colorsys.hls_to_rgb(*hls))
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def test_yiq_roundtrip(self):
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for r in frange(0.0, 1.0, 0.2):
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for g in frange(0.0, 1.0, 0.2):
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for b in frange(0.0, 1.0, 0.2):
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rgb = (r, g, b)
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self.assertTripleEqual(
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rgb,
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colorsys.yiq_to_rgb(*colorsys.rgb_to_yiq(*rgb))
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)
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def test_yiq_values(self):
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values = [
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# rgb, yiq
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((0.0, 0.0, 0.0), (0.0, 0.0, 0.0)), # black
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((0.0, 0.0, 1.0), (0.11, -0.3217, 0.3121)), # blue
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((0.0, 1.0, 0.0), (0.59, -0.2773, -0.5251)), # green
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((0.0, 1.0, 1.0), (0.7, -0.599, -0.213)), # cyan
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((1.0, 0.0, 0.0), (0.3, 0.599, 0.213)), # red
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((1.0, 0.0, 1.0), (0.41, 0.2773, 0.5251)), # purple
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((1.0, 1.0, 0.0), (0.89, 0.3217, -0.3121)), # yellow
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((1.0, 1.0, 1.0), (1.0, 0.0, 0.0)), # white
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((0.5, 0.5, 0.5), (0.5, 0.0, 0.0)), # grey
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]
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for (rgb, yiq) in values:
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self.assertTripleEqual(yiq, colorsys.rgb_to_yiq(*rgb))
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self.assertTripleEqual(rgb, colorsys.yiq_to_rgb(*yiq))
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if __name__ == "__main__":
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unittest.main()
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