Parameters

Gain Value

`gain'

Fixed

This value is multiplied by the original alpha channel value.

Offset Value

`offs'

Fixed

This value is added to the old alpha channel, after it has been multiplied by the gain parameter.

Top alpha pin

`pinT'

Fixed

The maximum value that the alpha channel can take after the gain and offset parameters have been applied.

Bottom alpha pin

`pinB'

Fixed

The minimum value that the alpha channel can take after the gain and offset parameters have been applied.