[vtkusers] vtkImageActor - changing display extent pb persists

[dean.inglis at camris.ca]

Hi, 

still having pbs  with vtkImageActor.  My data is
512 x 512 x 64 (x,y,z) and my pipeline is:  
vtkImageReader -> vtkImageMapTocolors -> vtkImageActor

running on a Win2k Intel P4 with NVIDIA GeForce card,
latest cvs vTK, MinSizeRel Borland compile.
This happens on two other Win2k systems so I 
dont think its a chip/driver/video card pb.

If I originally set the vtkImageActor display extents to 
0,511,511,0,0 and call GetWholeZMin, GetWholeZMax, I get
the expected 0, 63 respectively and the x-y plane data
displays correctly.  However, if I switch axes by setting
the display extent to 0,0,0,511,0,63 no image is
rendered by the actor and GetWholeZMin, GetWholeZMax still
returns 0,63 and not the expected 0,511!  

I am trying to use 1 vtkImageActor, and not 3 (one for each
anatomical axis).  Even though changing the DisplayExtent
forces the vtkImageActor to call Modified on itself, it does
not appear to be updating properly.  

Dean