# MouseEvents

VTKExamples/Cxx/Interaction/MouseEvents

### Description

This example shows how to subclass an interactor style to implement custom behaviors.

See MouseEventsObserver for a different approach that uses an existing interactor style class and adds an event observer to it.

### Code

MouseEvents.cxx

    #include <vtkRenderWindow.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkRenderer.h>
    #include <vtkSphereSource.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkSmartPointer.h>
    #include <vtkPointPicker.h>
    #include <vtkCamera.h>
    #include <vtkInteractorStyleTrackballCamera.h>
    #include <vtkObjectFactory.h>

    // Define interaction style
    class customMouseInteractorStyle : public vtkInteractorStyleTrackballCamera
    {
      public:
        static customMouseInteractorStyle* New();
        vtkTypeMacro(customMouseInteractorStyle, vtkInteractorStyleTrackballCamera);

        virtual void OnLeftButtonDown()
        {
          std::cout << "Pressed left mouse button." << std::endl;
          // Forward events
          vtkInteractorStyleTrackballCamera::OnLeftButtonDown();
        }

        virtual void OnMiddleButtonDown()
        {
          std::cout << "Pressed middle mouse button." << std::endl;
          // Forward events
          vtkInteractorStyleTrackballCamera::OnMiddleButtonDown();
        }

        virtual void OnRightButtonDown()
        {
          std::cout << "Pressed right mouse button." << std::endl;
          // Forward events
          vtkInteractorStyleTrackballCamera::OnRightButtonDown();
        }

    };

    vtkStandardNewMacro(customMouseInteractorStyle);

    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());

      vtkSmartPointer<vtkActor> actor =
          vtkSmartPointer<vtkActor>::New();
      actor->SetMapper(mapper);

      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      renderer->SetBackground(1,1,1); // Background color white
      renderer->AddActor(actor);

      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);

      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow ( renderWindow );

      vtkSmartPointer<customMouseInteractorStyle> style =
        vtkSmartPointer<customMouseInteractorStyle>::New();
      renderWindowInteractor->SetInteractorStyle( style );

      renderWindowInteractor->Initialize();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(MouseEvents)

    find_package(VTK REQUIRED)
    include(${VTK_USE_FILE})

    add_executable(MouseEvents MACOSX_BUNDLE MouseEvents.cxx)

    target_link_libraries(MouseEvents ${VTK_LIBRARIES})

### Download and Build MouseEvents

Click here to download MouseEvents and its CMakeLists.txt file. Once the tarball MouseEvents.tar has been downloaded and extracted,

    cd MouseEvents/build

If VTK is installed:

    cmake ..

If VTK is not installed but compiled on your system, you will need to specify the path to your VTK build:

    cmake -DVTK_DIR:PATH=/home/me/vtk_build ..

Build the project:

    make

and run it:

    ./MouseEvents

WINDOWS USERS PLEASE NOTE: Be sure to add the VTK bin directory to your path. This will resolve the VTK dll's at run time.