#!/usr/bin/env python
# -*- coding: utf-8 -*-
"""
Optimal Colour Stimuli - MacAdam Limits
=======================================
Defines objects related to optimal colour stimuli computations.
See Also
--------
`Optimal Colour Stimuli - MacAdam Limits IPython Notebook
<http://nbviewer.ipython.org/github/colour-science/colour-ipython/blob/master/notebooks/volume/macadam_limits.ipynb>`_ # noqa
"""
from __future__ import division, unicode_literals
import numpy as np
from colour.models import xyY_to_XYZ
from colour.volume import ILLUMINANTS_OPTIMAL_COLOUR_STIMULI
from colour.utilities import is_scipy_installed
__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__ = ['is_within_macadam_limits']
_XYZ_OPTIMAL_COLOUR_STIMULI_CACHE = {}
_XYZ_OPTIMAL_COLOUR_STIMULI_TRIANGULATIONS_CACHE = {}
def _XYZ_optimal_colour_stimuli(illuminant):
"""
Returns given illuminant optimal colour stimuli in *CIE XYZ* tristimulus
values and caches it if not existing.
Parameters
----------
illuminant : unicode
Illuminant.
Returns
-------
tuple
Illuminant optimal colour stimuli.
"""
optimal_colour_stimuli = ILLUMINANTS_OPTIMAL_COLOUR_STIMULI.get(illuminant)
if optimal_colour_stimuli is None:
raise KeyError(
'"{0}" not found in factory optimal colour stimuli: "{1}".'.format(
illuminant, sorted(ILLUMINANTS_OPTIMAL_COLOUR_STIMULI.keys())))
cached_ocs = _XYZ_OPTIMAL_COLOUR_STIMULI_CACHE.get(illuminant)
if cached_ocs is None:
_XYZ_OPTIMAL_COLOUR_STIMULI_CACHE[illuminant] = cached_ocs = (
xyY_to_XYZ(optimal_colour_stimuli) / 100)
return cached_ocs
[docs]def is_within_macadam_limits(xyY, illuminant, tolerance=None):
"""
Returns if given *CIE xyY* colourspace array is within MacAdam limits of
given illuminant.
Parameters
----------
xyY : array_like
*CIE xyY* colourspace array.
illuminant : unicode
Illuminant.
tolerance : numeric, optional
Tolerance allowed in the inside-triangle check.
Returns
-------
bool
Is within MacAdam limits.
Notes
-----
- Input *CIE xyY* colourspace array is in domain [0, 1].
- This definition requires *scipy* to be installed.
Examples
--------
>>> is_within_macadam_limits(np.array([0.3205, 0.4131, 0.51]), 'A')
array(True, dtype=bool)
>>> a = np.array([[0.3205, 0.4131, 0.51],
... [0.0005, 0.0031, 0.001]])
>>> is_within_macadam_limits(a, 'A')
array([ True, False], dtype=bool)
"""
if is_scipy_installed(raise_exception=True):
from scipy.spatial import Delaunay
optimal_colour_stimuli = _XYZ_optimal_colour_stimuli(illuminant)
triangulation = _XYZ_OPTIMAL_COLOUR_STIMULI_TRIANGULATIONS_CACHE.get(
illuminant)
if triangulation is None:
_XYZ_OPTIMAL_COLOUR_STIMULI_TRIANGULATIONS_CACHE[illuminant] = \
triangulation = Delaunay(optimal_colour_stimuli)
simplex = triangulation.find_simplex(xyY_to_XYZ(xyY), tol=tolerance)
simplex = np.where(simplex >= 0, True, False)
return simplex
Colour 0.3