[vtkusers] Bug in vtkExtractVOI?

[Dr. Uwe Köhler]

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Hi folks,

I have a problem and I am not sure if I missunderstood the pipeline execution 
or found a bug.

I use a vtkExtractVOI and it works fine the first time the pipeline is 
executed. When I change the extent using voiZ.SetVOI( extent ); I get the 
following error messages:

- ---------------------------------------------------------------------------------------
SetExtent: 20 236 20 236 9 9
Debug: In /usr/local/src/VTK_cvs/Imaging/vtkExtractVOI.h, line 55
vtkExtractVOI (0x822cff8): vtkExtractVOI (0x822cff8): setting VOI to 
(20,236,20,236,9,9)

ERROR: In /usr/local/src/VTK_cvs/Common/vtkDataObject.cxx, line 522
vtkImageData (0x822d090): Update extent does not lie within whole extent

ERROR: In /usr/local/src/VTK_cvs/Common/vtkDataObject.cxx, line 529
vtkImageData (0x822d090): Update extent is: 20, 236, 20, 236, 8, 8

ERROR: In /usr/local/src/VTK_cvs/Common/vtkDataObject.cxx, line 536
vtkImageData (0x822d090): Whole extent is: 20, 236, 20, 236, 9, 9

Debug: In /usr/local/src/VTK_cvs/Imaging/vtkExtractVOI.cxx, line 146
vtkExtractVOI (0x822cff8): Extracting VOI
- ---------------------------------------------------------------------------------------

These are the properties of the vtkExtractVOI Input and Output after the first 
use:
Input:
  Extent: (20, 236, 20, 236, 8, 8)
  WholeExtent: (20, 236, 20, 236, 3, 14)

Output:
  Extent: (20, 236, 20, 236, 8, 8)
  WholeExtent: (20, 236, 20, 236, 8, 8)

That looks fine to me. Resetting the Extent twice in a row works fine, as 
well. I had a look at the code and I cannot understand:
void vtkExtractVOI::ExecuteData(vtkDataObject *)
{
  vtkImageData *input=this->GetInput();
  vtkPointData *pd=input->GetPointData();
  vtkCellData *cd=input->GetCellData();
  vtkImageData *output = this->GetOutput();
  output->SetExtent(output->GetWholeExtent());
....

Shouldn`t that be output->SetExtent(input->GetWholeExtent());?

Well, I am puzzled.

Any help would be greatly welcome.

Uwe
- -- 
 |                                                                 |
- -+-----------------------------------------------------------------+-
 |  Dr. Uwe Köhler              MR - Physics                       | 
 |                              German Heart Institute Berlin      |
 |                              Augustenburger Platz 1             |
 |                              D - 13353 Berlin                   |
 |          ////                Germany                            |
 |         (@ @)                Phone: +49 172 98 11 598           |
- -+-----oOO--(_)--OOo-----------------------------------------------+-
 | <URL:http://www.ed.ac.uk/~ukoehler>   <mailto:UKoehler at dhzb.de> |
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