#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Common RGB Colour Models Utilities
==================================
Defines various RGB colour models common utilities.
See Also
--------
`RGB Colourspaces IPython Notebook
<http://nbviewer.jupyter.org/github/colour-science/colour-notebooks/\
blob/master/notebooks/models/rgb.ipynb>`_
"""
from __future__ import division, unicode_literals
from colour.models.rgb import RGB_COLOURSPACES, RGB_to_XYZ, XYZ_to_RGB
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013-2016 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['XYZ_to_sRGB', 'sRGB_to_XYZ']
[docs]def XYZ_to_sRGB(XYZ,
illuminant=RGB_COLOURSPACES.get('sRGB').whitepoint,
chromatic_adaptation_transform='CAT02',
apply_encoding_cctf=True):
"""
Converts from *CIE XYZ* tristimulus values to *sRGB* colourspace.
Parameters
----------
XYZ : array_like
*CIE XYZ* tristimulus values.
illuminant : array_like, optional
Source illuminant chromaticity coordinates.
chromatic_adaptation_transform : unicode, optional
**{'CAT02', 'XYZ Scaling', 'Von Kries', 'Bradford', 'Sharp',
'Fairchild', 'CMCCAT97', 'CMCCAT2000', 'CAT02_BRILL_CAT', 'Bianco',
'Bianco PC'}**,
*Chromatic adaptation* transform.
apply_encoding_cctf : bool, optional
Apply *sRGB* encoding colour component transfer function /
opto-electronic transfer function.
Returns
-------
ndarray
*sRGB* colour array.
Notes
-----
- Input *CIE XYZ* tristimulus values are in domain [0, 1].
Examples
--------
>>> import numpy as np
>>> XYZ = np.array([0.07049534, 0.10080000, 0.09558313])
>>> XYZ_to_sRGB(XYZ) # doctest: +ELLIPSIS
array([ 0.1749817..., 0.3881874..., 0.3215997...])
"""
sRGB = RGB_COLOURSPACES.get('sRGB')
return XYZ_to_RGB(XYZ,
illuminant,
sRGB.whitepoint,
sRGB.XYZ_to_RGB_matrix,
chromatic_adaptation_transform,
sRGB.encoding_cctf if apply_encoding_cctf else None)
[docs]def sRGB_to_XYZ(RGB,
illuminant=RGB_COLOURSPACES.get('sRGB').whitepoint,
chromatic_adaptation_method='CAT02',
apply_decoding_cctf=True):
"""
Converts from *sRGB* colourspace to *CIE XYZ* tristimulus values.
Parameters
----------
RGB : array_like
*sRGB* colourspace array.
illuminant : array_like, optional
Source illuminant chromaticity coordinates.
chromatic_adaptation_method : unicode, optional
**{'CAT02', 'XYZ Scaling', 'Von Kries', 'Bradford', 'Sharp',
'Fairchild', 'CMCCAT97', 'CMCCAT2000', 'CAT02_BRILL_CAT', 'Bianco',
'Bianco PC'}**,
*Chromatic adaptation* method.
apply_decoding_cctf : bool, optional
Apply *sRGB* decoding colour component transfer function /
electro-optical transfer function.
Returns
-------
ndarray
*CIE XYZ* tristimulus values.
Notes
-----
- Input *RGB* colourspace array is in domain [0, 1].
Examples
--------
>>> import numpy as np
>>> RGB = np.array([0.17498172, 0.38818743, 0.32159978])
>>> sRGB_to_XYZ(RGB) # doctest: +ELLIPSIS
array([ 0.0704953..., 0.1008..., 0.0955831...])
"""
sRGB = RGB_COLOURSPACES.get('sRGB')
return RGB_to_XYZ(RGB,
sRGB.whitepoint,
illuminant,
sRGB.RGB_to_XYZ_matrix,
chromatic_adaptation_method,
sRGB.decoding_cctf if apply_decoding_cctf else None)