[vtkusers] Circular Blending

[Garrett Jamie Cope]

I'm wondering if anyone has any ideas about how to iteratively blend
images with one of the blending filter inputs being the output of its
previous run. The idea is that I want the ability to essentially add
layers to an existing actor at different points during the app.

Due to the nature of the pipeline update, it seems that this isn't
possible. Once the pipeline is initiated for the second time, the blending
filter input that was formerly the last blended image will no longer be
so. The only solution I could think of was to chain a blend filter for
each new image to be blended, but this is not very efficient or desirable.

Does anyone have any ideas about how to get around this?

Thanks in advance,
Jamie