[vtkusers] question about the vtkImagePlaneWidget demo in the vtk package

[dean.inglis at camris.ca]

Hi,

in the code below there are two renderers in
one render window.  The render window gets
an interactor that monitors mouse events etc.
The widget gets connected to the render window
and one of its renderers when it sets the
interactor (see last line):



  vtkRenderer* ren1 = vtkRenderer::New();
  vtkRenderer* ren2 = vtkRenderer::New();

  vtkRenderWindow* renWin = vtkRenderWindow::New();
    renWin->AddRenderer(ren2);
    renWin->AddRenderer(ren1);// If I block this, the
vtkImagePlaneWidget will be automatically added to the ren2.

  vtkRenderWindowInteractor* iren = vtkRenderWindowInteractor::New();
    iren->SetRenderWindow(renWin);
	
  vtkCellPicker* picker = vtkCellPicker::New();
    picker->SetTolerance(0.005);

  vtkProperty* ipwProp = vtkProperty::New();
   //assign default props to the ipw's texture plane actor

  vtkImagePlaneWidget* planeWidgetX = vtkImagePlaneWidget::New();
    planeWidgetX->SetInteractor( iren);


By default, the widget will be rendered in the last
renderer added, which is why if you comment out 

renWin->AddRenderer(ren1);

the widget will be rendered in ren1.  If you want
to enforce which renderer to render it in, use the widget's
SetCurrentRenderer and SetDefaultRenderer methods which
are inherited from vtkInteractorObserver.

Dean