GPULevelsFilter constructor
GPULevelsFilter()
Photoshop-like levels adjustment.
The minimum, middle, maximum, minOutput and maxOutput parameters are floats in the range 0, 1
.
If you have parameters from Photoshop in the range 0, 255
you must first convert them to be 0, 1
.
The gamma/mid parameter is a float >= 0. This matches the value from Photoshop.
If you want to apply levels to RGB as well as individual channels you need to use this filter twice - first for the individual channels and then for all channels.
Implementation
GPULevelsFilter() {
type = "levels";
}