VTK/Examples/Cxx/Interaction/KeypressObserver

#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkSmartPointer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSphereSource.h>
#include <vtkCallbackCommand.h>
#include <vtkCommand.h>
 
void KeypressCallbackFunction (
  vtkObject* caller,
  long unsigned int eventId,
  void* clientData,
  void* callData );
 
int main(int, char *[])
{
  // Create a sphere
  vtkSmartPointer<vtkSphereSource> sphereSource = 
      vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(5.0);
  sphereSource->Update();
 
  vtkSmartPointer<vtkPolyDataMapper> mapper = 
    vtkSmartPointer<vtkPolyDataMapper>::New();
  mapper->SetInputConnection(sphereSource->GetOutputPort());
 
  // Create an actor
  vtkSmartPointer<vtkActor> actor = 
    vtkSmartPointer<vtkActor>::New();
  actor->SetMapper(mapper);
 
  // A renderer and render window
  vtkSmartPointer<vtkRenderer> renderer = 
    vtkSmartPointer<vtkRenderer>::New();
  vtkSmartPointer<vtkRenderWindow> renderWindow = 
    vtkSmartPointer<vtkRenderWindow>::New();
  renderWindow->AddRenderer(renderer);
 
  // An interactor
  vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor = 
    vtkSmartPointer<vtkRenderWindowInteractor>::New();
  renderWindowInteractor->SetRenderWindow(renderWindow);
 
  vtkSmartPointer<vtkCallbackCommand> keypressCallback = 
    vtkSmartPointer<vtkCallbackCommand>::New();
  keypressCallback->SetCallback ( KeypressCallbackFunction );
  renderWindowInteractor->AddObserver ( vtkCommand::KeyPressEvent, keypressCallback );
 
  renderer->AddActor(actor);
  renderer->SetBackground(1,1,1); // Background color white
  renderWindow->Render();
  renderWindowInteractor->Start();
 
  return EXIT_SUCCESS;
}
 
void KeypressCallbackFunction ( vtkObject* caller, long unsigned int vtkNotUsed(eventId), void* vtkNotUsed(clientData), void* vtkNotUsed(callData) )
{
  std::cout << "Keypress callback" << std::endl;
 
  vtkRenderWindowInteractor *iren = 
    static_cast<vtkRenderWindowInteractor*>(caller);
 
  std::cout << "Pressed: " << iren->GetKeySym() << std::endl;
}