[vtkusers] opposite of ComputeStructuredCoordinates? coords to voxel?

[Chase Yarbrough]

Hello,

I have structured coordinates and I need to figure out what voxel that
corresponds to.  Is there already a method for this?

The vtkImageData method ComputeStructuredCoordinates takes the
coordinates of a voxel and returns the structured coordinates, but I
need to go the other way around.

Thanks,
Chase