[vtkusers] Setting individual pixel's opacity.

[Sandarak]

Hello!

Is it possible in VTK to set individual pixel's opacity in the image?
Or is it possible to set opacity to pixels with the same value?

I'm working with an image of VTK_UNSIGNED_CHAR type and I would like
to set pixels with values 0  to be complately opaque, but I want to
have all other pixles visible.

I know that there is vtkLookupTable and I can use SetAlphaRange
method. But it doesn't solve the problem.

Thanks in advance

Michal