# Legend

VTKExamples/Cxx/Visualization/Legend

### Code

Legend.cxx

    #include <vtkVersion.h>
    #include <vtkPolyDataMapper.h>
    #include <vtkActor.h>
    #include <vtkRenderWindow.h>
    #include <vtkRenderer.h>
    #include <vtkRenderWindowInteractor.h>
    #include <vtkPolyData.h>
    #include <vtkCubeSource.h>
    #include <vtkSphereSource.h>
    #include <vtkLegendBoxActor.h>
    #include <vtkNamedColors.h>

    #include <vtkSmartPointer.h>

    int main (int, char *[])
    {
      vtkSmartPointer<vtkSphereSource> sphereSource =
        vtkSmartPointer<vtkSphereSource>::New();
      sphereSource->SetCenter(0.0, 0.0, 0.0);
      sphereSource->SetRadius(5000.0);
      sphereSource->Update();

      vtkPolyData* polydata = sphereSource->GetOutput();

      // Create a mapper
      vtkSmartPointer<vtkPolyDataMapper> mapper =
        vtkSmartPointer<vtkPolyDataMapper>::New();
    #if VTK_MAJOR_VERSION <= 5
      mapper->SetInput(polydata);
    #else
      mapper->SetInputData(polydata);
    #endif

      // 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<vtkLegendBoxActor> legend =
        vtkSmartPointer<vtkLegendBoxActor>::New();
      legend->SetNumberOfEntries(2);

      vtkSmartPointer<vtkNamedColors> colors =
        vtkSmartPointer<vtkNamedColors>::New();

      double color[4];

      vtkSmartPointer<vtkCubeSource> legendBox =
        vtkSmartPointer<vtkCubeSource>::New();
      legendBox->Update();
      colors->GetColor("tomato", color);
      legend->SetEntry(0, legendBox->GetOutput(), "Box", color);

      colors->GetColor("banana", color);
      legend->SetEntry(1, sphereSource->GetOutput(), "Ball", color);

      // place legend in lower right
      legend->GetPositionCoordinate()->SetCoordinateSystemToView();
      legend->GetPositionCoordinate()->SetValue(.5, -1.0);

      legend->GetPosition2Coordinate()->SetCoordinateSystemToView();
      legend->GetPosition2Coordinate()->SetValue(1.0, -0.5);

      legend->UseBackgroundOn();
      double background[4];
      colors->GetColor("warm_grey", background);
      legend->SetBackgroundColor(background);

      // Add the actors to the scene
      renderer->AddActor(actor);
      renderer->AddActor(legend);
      renderer->SetBackground(0,1,1); // Background color cyan

      // Render an image (lights and cameras are created automatically)
      renderWindow->Render();

      // Begin mouse interaction
      renderWindowInteractor->Start();

      return EXIT_SUCCESS;
    }

### CMakeLists.txt

    cmake_minimum_required(VERSION 2.8)

    PROJECT(Legend)

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

    add_executable(Legend MACOSX_BUNDLE Legend.cxx )

    target_link_libraries(Legend ${VTK_LIBRARIES})

### Download and Build Legend

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

    cd Legend/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:

    ./Legend

WINDOWS USERS

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