# SphereWidget

VTKExamples/Cxx/Widgets/SphereWidget

Other Languages

See (Python)

### Code

SphereWidget.cxx

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

    class SphereCallback : public vtkCommand
    {
      public:
        static SphereCallback *New()
        {
          return new SphereCallback;
        }
        SphereCallback(){}

        virtual void Execute(vtkObject *caller, unsigned long, void*)
        {

          vtkSphereWidget *sphereWidget =
              reinterpret_cast<vtkSphereWidget*>(caller);

          double center[3];
          sphereWidget->GetCenter(center);
          std::cout << "Center: " << center[0] << " " << center[1] << " " << center[2] << std::endl;
        }

    };

    int main(int, char *[])
    {
      // 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<vtkSphereWidget> sphereWidget =
        vtkSmartPointer<vtkSphereWidget>::New();
      sphereWidget->SetInteractor(renderWindowInteractor);
      sphereWidget->SetRepresentationToSurface();

      vtkSmartPointer<SphereCallback> sphereCallback =
        vtkSmartPointer<SphereCallback>::New();

      sphereWidget->AddObserver(vtkCommand::InteractionEvent,sphereCallback);

      renderWindow->Render();
      renderWindowInteractor->Initialize();
      renderWindow->Render();
      sphereWidget->On();
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 3.3 FATAL_ERROR)

    project(SphereWidget)

    find_package(VTK COMPONENTS
      vtkCommonCore
      vtkCommonDataModel
      vtkFiltersSources
      vtkInteractionStyle
      vtkInteractionWidgets
      vtkRenderingCore
      vtkRenderingFreeType
      vtkRenderingOpenGL2 QUIET)
    if (NOT VTK_FOUND)
      message("Skipping SphereWidget: ${VTK_NOT_FOUND_MESSAGE}")
      return ()
    endif()
    message (STATUS "VTK_VERSION: ${VTK_VERSION}")
    if (VTK_VERSION VERSION_LESS "8.90.0")
      # old system
      include(${VTK_USE_FILE})
      add_executable(SphereWidget MACOSX_BUNDLE SphereWidget.cxx )
      target_link_libraries(SphereWidget PRIVATE ${VTK_LIBRARIES})
    else ()
      # include all components
      add_executable(SphereWidget MACOSX_BUNDLE SphereWidget.cxx )
      target_link_libraries(SphereWidget PRIVATE ${VTK_LIBRARIES})
      # vtk_module_autoinit is needed
      vtk_module_autoinit(
        TARGETS SphereWidget
        MODULES ${VTK_LIBRARIES}
        )
    endif ()

### Download and Build SphereWidget

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

    cd SphereWidget/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:

    ./SphereWidget

WINDOWS USERS

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