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
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