# UserEvent

VTKExamples/Cxx/Interaction/UserEvent

### Code

UserEvent.cxx

    #include <vtkSphereSource.h>
    #include <vtkCallbackCommand.h>
    #include <vtkCommand.h>
    #include <vtkPolyData.h>
    #include <vtkSmartPointer.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>

    #include "vtkTestFilter.h"

    static void CallbackFunction(vtkObject* caller,
                    long unsigned int eventId,
                    void* clientData,
                    void* callData );

    int main(int, char *[])
    {
      // Create a renderer, render window, and interactor
      vtkSmartPointer<vtkRenderer> renderer =
        vtkSmartPointer<vtkRenderer>::New();
      vtkSmartPointer<vtkRenderWindow> renderWindow =
        vtkSmartPointer<vtkRenderWindow>::New();
      renderWindow->AddRenderer(renderer);
      vtkSmartPointer<vtkRenderWindowInteractor> renderWindowInteractor =
        vtkSmartPointer<vtkRenderWindowInteractor>::New();
      renderWindowInteractor->SetRenderWindow(renderWindow);

      vtkSmartPointer<vtkTestFilter> filter =
        vtkSmartPointer<vtkTestFilter>::New();

      vtkSmartPointer<vtkCallbackCommand> callback =
        vtkSmartPointer<vtkCallbackCommand>::New();
      callback->SetCallback(CallbackFunction );
      filter->AddObserver(filter->RefreshEvent, callback);

      filter->Update();

      renderWindow->Render();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

    void CallbackFunction(vtkObject* caller,
                    long unsigned int eventId,
                    void* clientData, void* callData )
    {
      std::cout << "CallbackFunction called." << std::endl;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(UserEvent)

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

    add_executable(UserEvent MACOSX_BUNDLE UserEvent.cxx)

    target_link_libraries(UserEvent ${VTK_LIBRARIES})

### Download and Build UserEvent

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

    cd UserEvent/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:

    ./UserEvent

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.