Method CreateCanonicalView

Rendering/Volume/vtkFixedPointVolumeRayCastMapper.cxx:1483–1600

Create an image into the vtkImageData argument. Used generally for creating thumbnail images

// Create an image into the vtkImageData argument. Used generally for
// creating thumbnail images
void vtkFixedPointVolumeRayCastMapper::CreateCanonicalView(
  vtkVolume* vol, vtkImageData* image, int blend_mode, double direction[3], double viewUp[3])
{
  // Make sure we have as long as we'd like so that the
  // image sample distance will be 1.0
  vol->SetAllocatedRenderTime(VTK_DOUBLE_MAX, nullptr);

  // Create a renderer / camera with the right parameters
  // These will never be mapped to the screen - just used
  // to hold parameters such as size, view direction, aspect,
  // etc.
  vtkRenderWindow* renWin = vtkRenderWindow::New();
  vtkRenderer* ren = vtkRenderer::New();
  vtkCamera* cam = ren->GetActiveCamera();

  renWin->AddRenderer(ren);
  int dim[3];
  image->GetDimensions(dim);

  // The size of the window is the size of the image
  renWin->SetSize(dim[0], dim[1]);

  double* center = vol->GetCenter();

  double bnds[6];
  vol->GetBounds(bnds);
#if 0
  double d = sqrt((bnds[1]-bnds[0])*(bnds[1]-bnds[0]) +
                  (bnds[3]-bnds[2])*(bnds[3]-bnds[2]) +
                  (bnds[5]-bnds[4])*(bnds[5]-bnds[4]));
#endif

  // For now use x distance - need to change this
  double d = bnds[1] - bnds[0];

  // Set up the camera in parallel
  cam->SetFocalPoint(center);
  cam->ParallelProjectionOn();
  cam->SetPosition(
    center[0] - d * direction[0], center[1] - d * direction[1], center[2] - d * direction[2]);
  cam->SetViewUp(viewUp);

  cam->SetParallelScale(d / 2);

  // Add a light
  vtkLight* light = vtkLight::New();
  light->SetPosition(
    center[0] - d * direction[0], center[1] - d * direction[1], center[2] - d * direction[2]);
  light->SetFocalPoint(center);
  ren->AddLight(light);

  int savedBlendMode = this->BlendMode;
  this->BlendMode = blend_mode;
  int savedCropping = this->Cropping;
  this->Cropping = 0;

  // Do all the initialization. This is not a multipass image
  // so just pass in dummy origin, spacing, and extent here