image_actors->PushActorsInto( window );
vtkSmartPointer< vtkImageActorPointPlacer > placer =
vtkSmartPointer< vtkImageActorPointPlacer >::New( );
image_actors->PushActorsInto( window );
vtkSmartPointer< vtkImageActorPointPlacer > placer =
vtkSmartPointer< vtkImageActorPointPlacer >::New( );