[vtkusers] Window->Image coordinate conversions?

[David Doria]

If I display an image in a render window, is there an interface to
convert between image and window coordinates? That is, if I have
zoomed/panned using a render window interactor and now I want to
retrieve the region in the original image that corresponds to a region
in the current display in the window. I can get the window coordinates
using a rubberband, but then I need to map those back to image(pixel)
coordinates. Is there any interface for this? Or do I need to directly
use the windows camera matrix, etc?

Thanks,

David