[vtkusers] VTKPointPicker getting negative values for y-axis

[Luis Roberto P. Paula]

Hi All,

I'm using the VTKPointPicker to get the coords of the mouse over a widget
displaying a vtkImageData object.

To display this image, I'm using the vtkImageViewer2.

The coords are get correctly when I use a blank image like this:

   vtlImageData* image = vtlImageData::New();
   image->SetSize(200, 200);
   image->AllocateScalars();
   image->Update();

When I use an image that was extracted from a 3D volume, the x-axis is
correct, but the y-axis is getting negative values.

Does anybody knows why this is happening? Is it an orientation problem? How
can I fix that?

This is the code to get the coords:

   if (!picker->Pick(this->Interactor->GetEventPosition()[0],
                     this->Interactor->GetEventPosition()[1],
                     0,
                     viewer->GetRenderer())) {
      return;
   }
   double ptMapped[3];
   picker->GetMapperPosition(ptMapped);

   double dSpacing[3];
   viewer->GetInput()->GetSpacing(dSpacing);
   ptMapped[2] = viewer->GetSlice() * dSpacing[2];

   // Update Image
   vtkImageData* image = vtkImageData::New();
   image->DeepCopy(this->editorGui->getImageMarker());

   int nVolIdx = viewer->GetInput()->FindPoint(ptMapped);
   unsigned short* pPix = (unsigned
short*)viewer->GetInput()->GetScalarPointer();
   int usPix = (int)pPix[nVolIdx];

   printf("Coords: x %f   y %f\n", ptMapped[0], ptMapped[1]);


Thanks,
Luis
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