[vtkusers] Image plane widget + color transfer function?

[Paul Melis]

Well, yes, that will make the image-to-colors object output alpha values.
But I see no way to *specify* the alpha values anywhere, as a 
vtkColorTransferFunction only takes RGB triplets.
Maybe I wasn't completely clear, but I want to set an alpha values per 
color table entry, not an overall alpha value for the whole IPW.

Paul

dean.inglis at camris.ca wrote:

>Hi Paul,
>
>ipw->GetColorMap()->SetOutputFormatToRGBA();
>
>should do the trick...
>
>
>*Hi Dean,
>
>Thanks! That does the trick.
>
>This feature does immediately raise the following question: is it 
>possible to have an image-plane widget with transparent areas (i.e. 
>colors with alpha < 1)  using a vtkColorTransferFunction? The latter 
>only handles colors, not opacities, and the only other option to pass to 
>ipw.GetColorMap().SetLookupTable() would be a vtkLookupTable which takes 
>me back to my original problem in not wanting to use that class, hmmm
>
>Paul
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