Set brightness, contrast, saturation and approximate gamma adjustment.

The filter accepts the following options:

contrast

Set the contrast value. It accepts a float value in range -2.0 to 2.0. The default value is 0.0.

brightness

Set the brightness value. It accepts a float value in range -1.0 to 1.0. The default value is 0.0.

saturation

Set the saturation value. It accepts a float value in range 0.0 to 3.0. The default value is 1.0.

gamma

Set the gamma value. It accepts a float value in range 0.1 to 10.0. The default value is 1.0.

gamma_r

Set the gamma value for red. It accepts a float value in range 0.1 to 10.0. The default value is 1.0.

gamma_g

Set the gamma value for green. It accepts a float value in range 0.1 to 10.0. The default value is 1.0.

gamma_b

Set the gamma value for blue. It accepts a float value in range 0.1 to 10.0. The default value is 1.0.

gamma_weight

Can be used to reduce the effect of a high gamma value on bright image areas, e.g. keep them from getting overamplified and just plain white. It accepts a float value in range 0.0 to 1.0.A value of 0.0 turns the gamma correction all the way down while 1.0 leaves it at its full strength. Default is 1.0.