#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
ProPhoto RGB Colourspace
========================
Defines the *ProPhoto RGB* colourspace:
- :attr:`PROPHOTO_RGB_COLOURSPACE`.
See Also
--------
`RGB Colourspaces IPython Notebook
<http://nbviewer.ipython.org/github/colour-science/colour-ipython/blob/master/notebooks/models/rgb.ipynb>`_ # noqa
References
----------
.. [1] ANSI. (2003). Specification of ROMM RGB. Retrieved from
http://www.color.org/ROMMRGB.pdf
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.colorimetry import ILLUMINANTS
from colour.models import RGB_Colourspace
__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__ = ['PROPHOTO_RGB_PRIMARIES',
'PROPHOTO_RGB_ILLUMINANT',
'PROPHOTO_RGB_WHITEPOINT',
'PROPHOTO_RGB_TO_XYZ_MATRIX',
'XYZ_TO_PROPHOTO_RGB_MATRIX',
'PROPHOTO_RGB_TRANSFER_FUNCTION',
'PROPHOTO_RGB_INVERSE_TRANSFER_FUNCTION',
'PROPHOTO_RGB_COLOURSPACE']
PROPHOTO_RGB_PRIMARIES = np.array(
[[0.7347, 0.2653],
[0.1596, 0.8404],
[0.0366, 0.0001]])
"""
*ProPhoto RGB* colourspace primaries.
PROPHOTO_RGB_PRIMARIES : ndarray, (3, 2)
"""
PROPHOTO_RGB_ILLUMINANT = 'D50'
"""
*ProPhoto RGB* colourspace whitepoint name as illuminant.
PROPHOTO_RGB_ILLUMINANT : unicode
"""
PROPHOTO_RGB_WHITEPOINT = ILLUMINANTS.get(
'CIE 1931 2 Degree Standard Observer').get(PROPHOTO_RGB_ILLUMINANT)
"""
*ProPhoto RGB* colourspace whitepoint.
PROPHOTO_RGB_WHITEPOINT : tuple
"""
PROPHOTO_RGB_TO_XYZ_MATRIX = np.array(
[[7.97667235e-01, 1.35192231e-01, 3.13525290e-02],
[2.88037454e-01, 7.11876883e-01, 8.56626476e-05],
[0.00000000e+00, 0.00000000e+00, 8.25188285e-01]])
"""
*ProPhoto RGB* colourspace to *CIE XYZ* colourspace matrix.
PROPHOTO_RGB_TO_XYZ_MATRIX : array_like, (3, 3)
"""
XYZ_TO_PROPHOTO_RGB_MATRIX = np.linalg.inv(PROPHOTO_RGB_TO_XYZ_MATRIX)
"""
*CIE XYZ* colourspace to *ProPhoto RGB* colourspace matrix.
XYZ_TO_PROPHOTO_RGB_MATRIX : array_like, (3, 3)
"""
def _prophoto_rgb_transfer_function(value):
"""
Defines the *ProPhoto RGB* value colourspace transfer function.
Parameters
----------
value : numeric
value.
Returns
-------
numeric
Companded value.
"""
return value * 16 if value < 0.001953 else value ** (1 / 1.8)
def _prophoto_rgb_inverse_transfer_function(value):
"""
Defines the *ProPhoto RGB* value colourspace inverse transfer
function.
Parameters
----------
value : numeric
value.
Returns
-------
numeric
Companded value.
"""
return (value / 16
if value < _prophoto_rgb_transfer_function(0.001953) else
value ** 1.8)
PROPHOTO_RGB_TRANSFER_FUNCTION = _prophoto_rgb_transfer_function
"""
Transfer function from linear to *ProPhoto RGB* colourspace.
PROPHOTO_RGB_TRANSFER_FUNCTION : object
"""
PROPHOTO_RGB_INVERSE_TRANSFER_FUNCTION = (
_prophoto_rgb_inverse_transfer_function)
"""
Inverse transfer function from *ProPhoto RGB* colourspace to linear.
PROPHOTO_RGB_INVERSE_TRANSFER_FUNCTION : object
"""
PROPHOTO_RGB_COLOURSPACE = RGB_Colourspace(
'ProPhoto RGB',
PROPHOTO_RGB_PRIMARIES,
PROPHOTO_RGB_WHITEPOINT,
PROPHOTO_RGB_ILLUMINANT,
PROPHOTO_RGB_TO_XYZ_MATRIX,
XYZ_TO_PROPHOTO_RGB_MATRIX,
PROPHOTO_RGB_TRANSFER_FUNCTION,
PROPHOTO_RGB_INVERSE_TRANSFER_FUNCTION)
"""
*ProPhoto RGB* colourspace.
PROPHOTO_RGB_COLOURSPACE : RGB_Colourspace
"""
Colour 0.3