[vtkusers] vtkImagePlaneWidget: interpolated cursor position

[John Hunter]

I am using a vtkImagePlaneWidget and get the current cursor position
and voxel with

  pw.GetCursorData(xyzv)

However, this returns the position in the (not interpolated) image
data.  As you smoothly drag the mouse across the image plane the
position makes discrete integer jumps from one voxel position to
another.  Is there an easy way to get the interpolated position of the
mouse pointer using the IPW functionality?

Thanks!
John Hunter
VTK-4.3