colour.gamma_function

colour.gamma_function(a: ArrayLike, exponent: ArrayLike = 1, negative_number_handling: Literal['Clamp', 'Indeterminate', 'Mirror', 'Preserve'] | str = 'Indeterminate') → NDArrayFloat

Apply a gamma encoding or decoding transformation to the specified array.

Parameters:

• a (ArrayLike) – Array to encode or decode.

• exponent (ArrayLike) – Encoding or decoding exponent.

• negative_number_handling (Literal['Clamp', 'Indeterminate', 'Mirror', 'Preserve'] | str) –

  Behaviour for a negative numbers and the definition return value:

  • Indeterminate: The behaviour will be indeterminate and the definition return value might contain nans.

  • Mirror: The definition return value will be mirrored around the abscissa and ordinate axes, i.e., Blackmagic Design: Davinci Resolve behaviour.

  • Preserve: The definition will preserve any negative number in a, i.e., The Foundry Nuke behaviour.

  • Clamp: The definition will clamp any negative number in a to 0.

Returns:

Encoded or decoded array.

Return type:

numpy.ndarray

Examples

>>> gamma_function(0.18, 2.2)
0.0229932...
>>> gamma_function(-0.18, 2.0)
0.0323999...
>>> gamma_function(-0.18, 2.2)
nan
>>> gamma_function(-0.18, 2.2, "Mirror")
-0.0229932...
>>> gamma_function(-0.18, 2.2, "Preserve")
-0.1...
>>> gamma_function(-0.18, 2.2, "Clamp")
0.0