[vtkusers] Problems saving images from vtk windows

[Julian Humphries]

I have figured out several ways to save images to a
file from both imageviewer windows and ordinary
render windows(e.g. using WindowToImage filters, writer.
SetInput and SaveWindowAsPPM).  All methods I have tried 
seem to do a very simple bitmap copy off the screen(buffer)
such that any other windows that lie over the vtk
window appear in the resulting saved image.  At least
this is true in the MS Windows environment. This makes
tasks like image reslicing very tough to execute cleanly.

Is there a way to save a vtkobject  (e.g. a resliced
slice) to an image file, either without displaying to the
screen, or as a image that reflects only the contents of
the vtk window?

Thanks in advance, Julian Humphries