[vtkusers] Best way to get all ImageData pixels under an actor

[David Doria]

If you use vtkImageTracerWidget
http://www.vtk.org/Wiki/VTK/Examples/Widgets/ImageTracerWidget

and set the LineWidth to draw a thick line, is there a fast way to
determine which pixels in the image have been drawn on? The GetPath
function of the widget returns a polydata with the points in the
center of the stroke, but I'm interested in the set of pixels (no
longer a path, just a list of pixels) that projection of the thick
line actor onto the image would land on.

Any thoughts on how to do this?

Thanks,

David