#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Deprecated Colour Models Transformations
========================================
Defines various deprecated colour models transformations:
- :func:`RGB_to_HSV`
- :func:`HSV_to_RGB`
- :func:`RGB_to_HSL`
- :func:`HSL_to_RGB`
- :func:`RGB_to_CMY`
- :func:`CMY_to_RGB`
- :func:`CMY_to_CMYK`
- :func:`CMYK_to_CMY`
- :func:`RGB_to_HEX`
- :func:`HEX_to_RGB`
These colour models are stated as deprecated because they trade off perceptual
relevance for computation speed. They should not be used in the colour science
domain although they are useful for image analysis and provide end user
software colour selection tools.
They are provided for convenience and completeness.
Warning
-------
Don't use that! Seriously...
References
----------
.. [1] http://en.wikipedia.org/wiki/HSL_and_HSV
(Last accessed 10 August 2014)
.. [2] `Color Gamut Transform Pairs
<http://alvyray.com/Papers/CG/color78.pdf>`_,
DOI: https://doi.org/10.1145/800248.807361
(Last accessed 10 August 2014)
"""
from __future__ import division, unicode_literals
import math
import numpy as np
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013 - 2014 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['RGB_to_HSV',
'HSV_to_RGB',
'RGB_to_HSL',
'HSL_to_RGB',
'RGB_to_CMY',
'CMY_to_RGB',
'CMY_to_CMYK',
'CMYK_to_CMY',
'RGB_to_HEX',
'HEX_to_RGB']
[docs]def RGB_to_HSV(RGB):
"""
Converts from *RGB* colourspace to *HSV* colourspace.
Parameters
----------
RGB : array_like, (3,)
*RGB* colourspace matrix.
Returns
-------
ndarray, (3,)
*HSV* matrix.
Notes
-----
- Input *RGB* colourspace matrix is in domain [0, 1].
- Output *HSV* colourspace matrix is in domain [0, 1].
References
----------
.. [3] http://www.easyrgb.com/index.php?X=MATH&H=20#text20
(Last accessed 18 May 2014)
Examples
--------
>>> RGB = np.array([0.49019608, 0.98039216, 0.25098039])
>>> RGB_to_HSV(RGB) # doctest: +ELLIPSIS
array([ 0.2786738..., 0.744 , 0.98039216])
"""
R, G, B = np.ravel(RGB)
minimum = min(R, G, B)
maximum = max(R, G, B)
delta = maximum - minimum
V = maximum
if delta == 0:
H = 0
S = 0
else:
S = delta / maximum
delta_R = (((maximum - R) / 6) + (delta / 2)) / delta
delta_G = (((maximum - G) / 6) + (delta / 2)) / delta
delta_B = (((maximum - B) / 6) + (delta / 2)) / delta
if R == maximum:
H = delta_B - delta_G
elif G == maximum:
H = (1 / 3) + delta_R - delta_B
elif B == maximum:
H = (2 / 3) + delta_G - delta_R
if H < 0:
H += 1
if H > 1:
H -= 1
return np.array([H, S, V])
[docs]def HSV_to_RGB(HSV):
"""
Converts from *HSV* colourspace to *RGB* colourspace.
Parameters
----------
HSV : array_like, (3,)
*HSV* colourspace matrix.
Returns
-------
ndarray, (3,)
*RGB* colourspace matrix.
Notes
-----
- Input *HSV* colourspace matrix is in domain [0, 1].
- Output *RGB* colourspace matrix is in domain [0, 1].
References
----------
.. [4] http://www.easyrgb.com/index.php?X=MATH&H=21#text21
(Last accessed 18 May 2014)
Examples
--------
>>> HSV = np.array([0.27867384, 0.744, 0.98039216])
>>> HSV_to_RGB(HSV) # doctest: +ELLIPSIS
array([ 0.4901960..., 0.9803921..., 0.2509803...])
"""
H, S, V = np.ravel(HSV)
if S == 0:
R = V
G = V
B = V
else:
h = H * 6
if h == 6:
h = 0
i = math.floor(h)
j = V * (1 - S)
k = V * (1 - S * (h - i))
l = V * (1 - S * (1 - (h - i)))
if i == 0:
R = V
G = l
B = j
elif i == 1:
R = k
G = V
B = j
elif i == 2:
R = j
G = V
B = l
elif i == 3:
R = j
G = k
B = V
elif i == 4:
R = l
G = j
B = V
elif i == 5:
R = V
G = j
B = k
return np.array([R, G, B])
[docs]def RGB_to_HSL(RGB):
"""
Converts from *RGB* colourspace to *HSL* colourspace.
Parameters
----------
RGB : array_like, (3,)
*RGB* colourspace matrix.
Returns
-------
ndarray, (3,)
*HSL* matrix.
Notes
-----
- Input *RGB* colourspace matrix is in domain [0, 1].
- Output *HSL* colourspace matrix is in domain [0, 1].
References
----------
.. [5] http://www.easyrgb.com/index.php?X=MATH&H=18#text18
(Last accessed 18 May 2014)
Examples
--------
>>> RGB = np.array([0.49019608, 0.98039216, 0.25098039])
>>> RGB_to_HSL(RGB) # doctest: +ELLIPSIS
array([ 0.2786738..., 0.9489796..., 0.6156862...])
"""
R, G, B = np.ravel(RGB)
minimum = min(R, G, B)
maximum = max(R, G, B)
delta = maximum - minimum
L = (maximum + minimum) / 2
if delta == 0:
H = 0
S = 0
else:
S = delta / (maximum + minimum) if L < 0.5 else delta / (
2 - maximum - minimum)
delta_R = (((maximum - R) / 6) + (delta / 2)) / delta
delta_G = (((maximum - G) / 6) + (delta / 2)) / delta
delta_B = (((maximum - B) / 6) + (delta / 2)) / delta
if R == maximum:
H = delta_B - delta_G
elif G == maximum:
H = (1 / 3) + delta_R - delta_B
elif B == maximum:
H = (2 / 3) + delta_G - delta_R
if H < 0:
H += 1
if H > 1:
H -= 1
return np.array([H, S, L])
[docs]def HSL_to_RGB(HSL):
"""
Converts from *HSL* colourspace to *RGB* colourspace.
Parameters
----------
HSL : array_like, (3,)
*HSL* colourspace matrix.
Returns
-------
ndarray, (3,)
*RGB* colourspace matrix.
Notes
-----
- Input *HSL* colourspace matrix is in domain [0, 1].
- Output *RGB* colourspace matrix is in domain [0, 1].
References
----------
.. [6] http://www.easyrgb.com/index.php?X=MATH&H=19#text19
(Last accessed 18 May 2014)
Examples
--------
>>> HSL = np.array([0.27867384, 0.94897959, 0.61568627])
>>> HSL_to_RGB(HSL) # doctest: +ELLIPSIS
array([ 0.4901960..., 0.9803921..., 0.2509803...])
"""
H, S, L = np.ravel(HSL)
if S == 1:
R = L
G = L
B = L
else:
def H_to_RGB(vi, vj, vH):
"""
Converts *hue* value to *RGB* colourspace.
"""
if vH < 0:
vH += 1
if vH > 1:
vH -= 1
if 6 * vH < 1:
return vi + (vj - vi) * 6 * vH
if 2 * vH < 1:
return vj
if 3 * vH < 2:
return vi + (vj - vi) * ((2 / 3) - vH) * 6
return vi
j = L * (1 + S) if L < 0.5 else (L + S) - (S * L)
i = 2 * L - j
R = H_to_RGB(i, j, H + (1 / 3))
G = H_to_RGB(i, j, H)
B = H_to_RGB(i, j, H - (1 / 3))
return np.array([R, G, B])
[docs]def RGB_to_CMY(RGB):
"""
Converts from *RGB* colourspace to *CMY* colourspace.
Parameters
----------
RGB : array_like, (3,)
*RGB* colourspace matrix.
Returns
-------
ndarray, (3,)
*CMY* matrix.
Notes
-----
- Input *RGB* colourspace matrix is in domain [0, 1].
- Output *CMY* colourspace matrix is in domain [0, 1].
References
----------
.. [7] http://www.easyrgb.com/index.php?X=MATH&H=11#text11
(Last accessed 18 May 2014)
Examples
--------
>>> RGB = np.array([0.49019608, 0.98039216, 0.25098039])
>>> RGB_to_CMY(RGB) # doctest: +ELLIPSIS
array([ 0.5098039..., 0.0196078..., 0.7490196...])
"""
R, G, B = np.ravel(RGB)
return np.array([1 - R, 1 - G, 1 - B])
[docs]def CMY_to_RGB(CMY):
"""
Converts from *CMY* colourspace to *CMY* colourspace.
Parameters
----------
CMY : array_like, (3,)
*CMY* colourspace matrix.
Returns
-------
ndarray, (3,)
*RGB* colourspace matrix.
Notes
-----
- Input *CMY* colourspace matrix is in domain [0, 1].
- Output *RGB* colourspace matrix is in domain [0, 1].
References
----------
.. [8] http://www.easyrgb.com/index.php?X=MATH&H=12#text12
(Last accessed 18 May 2014)
Examples
--------
>>> CMY = np.array([0.50980392, 0.01960784, 0.74901961])
>>> CMY_to_RGB(CMY) # doctest: +ELLIPSIS
array([ 0.4901960..., 0.9803921..., 0.2509803...])
"""
C, M, Y = np.ravel(CMY)
return np.array([1 - C, 1 - M, 1 - Y])
[docs]def CMY_to_CMYK(CMY):
"""
Converts from *CMY* colourspace to *CMYK* colourspace.
Parameters
----------
CMY : array_like, (3,)
*CMY* colourspace matrix.
Returns
-------
ndarray, (4,)
*CMYK* matrix.
Notes
-----
- Input *CMY* colourspace matrix is in domain [0, 1].
- Output*CMYK* colourspace matrix is in domain [0, 1].
References
----------
.. [9] http://www.easyrgb.com/index.php?X=MATH&H=13#text13
(Last accessed 18 May 2014)
Examples
--------
>>> CMY = np.array([0.50980392, 0.01960784, 0.74901961])
>>> CMY_to_CMYK(CMY) # doctest: +ELLIPSIS
array([ 0.5 , 0. , 0.744 , 0.0196078...])
"""
C, M, Y = np.ravel(CMY)
K = 1
if C < K:
K = C
if M < K:
K = M
if Y < K:
K = Y
if K == 1:
C = 0
M = 0
Y = 0
else:
C = (C - K) / (1 - K)
M = (M - K) / (1 - K)
Y = (Y - K) / (1 - K)
return np.array([C, M, Y, K])
[docs]def CMYK_to_CMY(CMYK):
"""
Converts from *CMYK* colourspace to *CMY* colourspace.
Parameters
----------
CMYK : array_like, (4,)
*CMYK* colourspace matrix.
Returns
-------
ndarray, (3,)
*CMY* matrix.
Notes
-----
- Input *CMYK* colourspace matrix is in domain [0, 1].
- Output *CMY* colourspace matrix is in domain [0, 1].
References
----------
.. [10] http://www.easyrgb.com/index.php?X=MATH&H=14#text14
(Last accessed 18 May 2014)
Examples
--------
>>> CMYK = np.array([0.5, 0, 0.744, 0.01960784])
>>> CMYK_to_CMY(CMYK) # doctest: +ELLIPSIS
array([ 0.5098039..., 0.0196078..., 0.7490196...])
"""
C, M, Y, K = np.ravel(CMYK)
return np.array(
[C * (1 - K) + K, M * (1 - K) + K, Y * (1 - K) + K])
[docs]def RGB_to_HEX(RGB):
"""
Converts from *RGB* colourspace to hex triplet representation.
Parameters
----------
RGB : array_like, (3,)
*RGB* colourspace matrix.
Returns
-------
unicode
Hex triplet representation.
Notes
-----
- Input *RGB* colourspace matrix is in domain [0, 1].
Examples
--------
>>> RGB = np.array([0.66666667, 0.86666667, 1])
>>> # Doctests skip for Python 2.x compatibility.
>>> RGB_to_HEX(RGB) # doctest: +SKIP
'#aaddff'
"""
RGB = np.ravel(RGB)
R, G, B = map(int, RGB * 255)
return '#{0:02x}{1:02x}{2:02x}'.format(R, G, B)
[docs]def HEX_to_RGB(HEX):
"""
Converts from hex triplet representation to *RGB* colourspace.
Parameters
----------
HEX : unicode
Hex triplet representation.
Returns
-------
ndarray, (3,)
*RGB* colourspace matrix.
Notes
-----
- Output *RGB* colourspace matrix is in domain [0, 1].
Examples
--------
>>> HEX = '#aaddff'
>>> HEX_to_RGB(HEX) # doctest: +ELLIPSIS
array([ 0.6666666..., 0.8666666..., 1. ])
"""
HEX = HEX.lstrip('#')
length = len(HEX)
return np.array([int(HEX[i:i + length // 3], 16) for i in
range(0, length, length // 3)]) / 255
Colour 0.3