VTK/Examples/Cxx/Visualization/Legend

#include <vtkVersion.h>
#include <vtkPolyDataMapper.h>
#include <vtkActor.h>
#include <vtkRenderWindow.h>
#include <vtkRenderer.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkPolyData.h>
#include <vtkSphereSource.h>
#include <vtkLegendBoxActor.h>
#include <vtkSmartPointer.h>
 
int main (int, char *[])
{
  vtkSmartPointer<vtkSphereSource> sphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();
  sphereSource->SetCenter(0.0, 0.0, 0.0);
  sphereSource->SetRadius(5.0);
  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);
  double color[3] = {1,0,0};
  legend->SetEntry(0, static_cast<vtkPolyData *> (NULL), "test", color);
  vtkSmartPointer<vtkSphereSource> legendSphereSource = 
    vtkSmartPointer<vtkSphereSource>::New();
  vtkSmartPointer<vtkPolyData> legendSphere = legendSphereSource->GetOutput();
  legend->SetEntry(1, legendSphere, "test", color);
 
  // Add the actors to the scene
  renderer->AddActor(actor);
  renderer->AddActor(legend);
  renderer->SetBackground(0,1,1); // Background color white
 
  // Render an image (lights and cameras are created automatically)
  renderWindow->Render();
 
  // Begin mouse interaction
  renderWindowInteractor->Start();
 
  return EXIT_SUCCESS;
}