[vtkusers] change contrast in volume object (it's too dark)

[powerhouseofexcellence]

Hello,

I have a volume rendering going on, but the contrast of the volume is
very poor, it's kind of difficult to see. Is there a way to implement
a window/level function on the volume object? Or do I shift the values
in my opacity/color transfer functions to create a window/level type
effect?

Thanks