#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
ECI RGB v2 Colourspace
======================
Defines the *ECI RGB v2* colourspace:
- :attr:`ECI_RGB_V2_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] European Color Initiative. (2002). ECI RGB v2. Retrieved from
http://www.eci.org/_media/downloads/icc_profiles_from_eci/ecirgbv20.zip
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.colorimetry import ILLUMINANTS, lightness_1976, luminance_1976
from colour.models import RGB_Colourspace, normalised_primary_matrix
__author__ = 'Colour Developers'
__copyright__ = 'Copyright (C) 2013 - 2015 - Colour Developers'
__license__ = 'New BSD License - http://opensource.org/licenses/BSD-3-Clause'
__maintainer__ = 'Colour Developers'
__email__ = 'colour-science@googlegroups.com'
__status__ = 'Production'
__all__ = ['ECI_RGB_V2_PRIMARIES',
'ECI_RGB_V_ILLUMINANT',
'ECI_RGB_V2_WHITEPOINT',
'ECI_RGB_V2_TO_XYZ_MATRIX',
'XYZ_TO_ECI_RGB_V2_MATRIX',
'ECI_RGB_V2_TRANSFER_FUNCTION',
'ECI_RGB_V2_INVERSE_TRANSFER_FUNCTION',
'ECI_RGB_V2_COLOURSPACE']
ECI_RGB_V2_PRIMARIES = np.array(
[[0.670103092783505220, 0.329896907216494840],
[0.209905660377358470, 0.709905660377358360],
[0.140061791967044270, 0.080329557157569509]])
"""
*ECI RGB v2* colourspace primaries.
ECI_RGB_V2_PRIMARIES : ndarray, (3, 2)
"""
ECI_RGB_V_ILLUMINANT = 'D50'
"""
*ECI RGB v2* colourspace whitepoint name as illuminant.
ECI_RGB_V_ILLUMINANT : unicode
"""
ECI_RGB_V2_WHITEPOINT = ILLUMINANTS.get(
'CIE 1931 2 Degree Standard Observer').get(ECI_RGB_V_ILLUMINANT)
"""
*ECI RGB v2* colourspace whitepoint.
ECI_RGB_V2_WHITEPOINT : tuple
"""
ECI_RGB_V2_TO_XYZ_MATRIX = normalised_primary_matrix(ECI_RGB_V2_PRIMARIES,
ECI_RGB_V2_WHITEPOINT)
"""
*ECI RGB v2* colourspace to *CIE XYZ* tristimulus values matrix.
ECI_RGB_V2_TO_XYZ_MATRIX : array_like, (3, 3)
"""
XYZ_TO_ECI_RGB_V2_MATRIX = np.linalg.inv(ECI_RGB_V2_TO_XYZ_MATRIX)
"""
*CIE XYZ* tristimulus values to *ECI RGB v2* colourspace matrix.
XYZ_TO_ECI_RGB_V2_MATRIX : array_like, (3, 3)
"""
def _eci_rgb_v2_transfer_function(value):
"""
Defines the *ECI RGB v2* colourspace transfer function.
Parameters
----------
value : numeric or array_like
Value.
Returns
-------
numeric or ndarray
Companded value.
"""
return lightness_1976(value * 100) / 100
def _eci_rgb_v2_inverse_transfer_function(value):
"""
Defines the *ECI RGB v2* colourspace inverse transfer function.
Parameters
----------
value : numeric or array_like
Value.
Returns
-------
numeric or ndarray
Companded value.
"""
return luminance_1976(value * 100) / 100
ECI_RGB_V2_TRANSFER_FUNCTION = _eci_rgb_v2_transfer_function
"""
Transfer function from linear to *ECI RGB v2* colourspace.
ECI_RGB_V2_TRANSFER_FUNCTION : object
"""
ECI_RGB_V2_INVERSE_TRANSFER_FUNCTION = _eci_rgb_v2_inverse_transfer_function
"""
Inverse transfer function from *ECI RGB v2* colourspace to linear.
ECI_RGB_V2_INVERSE_TRANSFER_FUNCTION : object
"""
ECI_RGB_V2_COLOURSPACE = RGB_Colourspace(
'ECI RGB v2',
ECI_RGB_V2_PRIMARIES,
ECI_RGB_V2_WHITEPOINT,
ECI_RGB_V_ILLUMINANT,
ECI_RGB_V2_TO_XYZ_MATRIX,
XYZ_TO_ECI_RGB_V2_MATRIX,
ECI_RGB_V2_TRANSFER_FUNCTION,
ECI_RGB_V2_INVERSE_TRANSFER_FUNCTION)
"""
*ECI RGB v2* colourspace.
ECI_RGB_V2_COLOURSPACE : RGB_Colourspace
"""
Colour 0.3