colour.xy_to_xyY

colour.xy_to_xyY(xy, Y=1)[source]

Converts from xy chromaticity coordinates to CIE xyY colourspace by extending the array last dimension with \(Y\) Luminance.

xy argument with last dimension being equal to 3 will be assumed to be a CIE xyY colourspace array argument and will be returned directly by the definition.

Parameters:
  • xy (array_like) – xy chromaticity coordinates or CIE xyY colourspace array.
  • Y (numeric, optional) – Optional \(Y\) Luminance value used to construct the CIE xyY colourspace array, otherwise the \(Y\) Luminance will be set to 1.
Returns:

CIE xyY colourspace array.
Return type:

ndarray

Notes

  • This definition is a convenient object provided to implement support of illuminant argument luminance value in various colour.models package objects such as colour.Lab_to_XYZ() or colour.Luv_to_XYZ().
  • Input xy chromaticity coordinates are in domain [0, 1].
  • Output CIE xyY colourspace array is in range [0, 1].

References

Examples

>>> xy = np.array([0.26414772, 0.37770001])
>>> xy_to_xyY(xy)  
array([ 0.2641477...,  0.3777000...,  1.        ])
>>> xy = np.array([0.26414772, 0.37770001, 0.10080000])
>>> xy_to_xyY(xy)  
array([ 0.2641477...,  0.3777000...,  0.1008...])
>>> xy = np.array([0.26414772, 0.37770001])
>>> xy_to_xyY(xy, 100)  
array([   0.2641477...,    0.3777000...,  100.        ])