[vtk-developers] Failed to locate vtkImageActor to the center of outline

[XiongXiang Zhang]

Hi,
We try to locate a instance of vtkImageActor at the center of a cube, but not at the correct location.Our code as the
following:
 
//instance  OutlineFilter, imagedata is type of vtkImageData
 vtkSmartPointer<vtkOutlineFilter> outlineData = vtkSmartPointer<vtkOutlineFilter>::New();
  outlineData->SetInput(imagedata);
  outlineData->Update();

  vtkSmartPointer<vtkPolyDataMapper> mapOutline =vtkSmartPointer<vtkPolyDataMapper>::New();
  mapOutline->SetInputConnection(outlineData->GetOutputPort());

  vtkSmartPointer<vtkActor> outline = vtkSmartPointer<vtkActor>::New();
  outline->SetMapper(mapOutline);
  outline->GetProperty()->SetColor(0,0,0);

  ren->AddActor(outline);
 
//get the center of the outline
 outline->GetBounds(bounds);
   width[0]=bounds[1]-bounds[0];
   width[1]=bounds[3]-bounds[2];
   width[2]=bounds[5]-bounds[4];
   center[0]=bounds[0]+width[0]*0.5;
   center[1]=bounds[2]+width[1]*0.5;
   center[2]=bounds[4]+width[2]*0.5;
 
//instance vtkImageMapToColors
vtkSmartPointer<vtkImageMapToColors> axialColors = vtkSmartPointer<vtkImageMapToColors>::New();
  axialColors->SetInput(imagedata);
  axialColors->Update();
 
//add axialColors to ImageActor
  vtkSmartPointer<vtkImageActor> axial =vtkSmartPointer<vtkImageActor>::New();
  axial->SetInput(axialColors->GetOutput());
  axial->SetDisplayExtent(bounds[0],bounds[1], bounds[2],bounds[3],center[2],center[2]);//the center of Z axis
 
We use the method of "vtkImageActor::SetDisplayExtent" to locate the imageactor at the center of the outline, but
it not at the center. The result shown in the attached image "result.png". We don't modify the coordinate system
(all  are default). How could we solve this problem.
The version of VTK is 5.10.0, which is compiled from source, our systerm is Windows XP (SP3).
Thanks!
 
XiongXiang Zhang
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