VTK/Examples/Cxx/Interaction/KeypressEvents

#include <vtkPolyDataMapper.h>
#include <vtkObjectFactory.h>
#include <vtkActor.h>
#include <vtkSmartPointer.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSphereSource.h>
#include <vtkInteractorStyleTrackballCamera.h>
 
// Define interaction style
class KeyPressInteractorStyle : public vtkInteractorStyleTrackballCamera
{
  public:
    static KeyPressInteractorStyle* New();
    vtkTypeMacro(KeyPressInteractorStyle, vtkInteractorStyleTrackballCamera);
 
    virtual void OnKeyPress() 
    {
      // Get the keypress
      vtkRenderWindowInteractor *rwi = this->Interactor;
      std::string key = rwi->GetKeySym();
 
      // Output the key that was pressed
      std::cout << "Pressed " << key << std::endl;
 
      // Handle an arrow key
      if(key == "Up")
        {
        std::cout << "The up arrow was pressed." << std::endl;
        }
 
      // Handle a "normal" key
      if(key == "a")
        {
        std::cout << "The a key was pressed." << std::endl;
        }
 
      // Forward events
      vtkInteractorStyleTrackballCamera::OnKeyPress();
    }
 
};
vtkStandardNewMacro(KeyPressInteractorStyle);
 
int main(int, char *[])
{
  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<KeyPressInteractorStyle> style = 
    vtkSmartPointer<KeyPressInteractorStyle>::New();
  renderWindowInteractor->SetInteractorStyle(style);
  style->SetCurrentRenderer(renderer);
 
  renderer->AddActor(actor);
  renderer->SetBackground(1,1,1); // Background color white
 
  renderWindow->Render();
 
  renderWindowInteractor->Start();
 
  return EXIT_SUCCESS;
}