BackgroundGradient

import vtk.vtkActor;
import vtk.vtkSphereSource;
import vtk.vtkNativeLibrary;
import vtk.vtkPolyDataMapper;

import vtk.vtkRenderWindow;
import vtk.vtkNamedColors;
import vtk.vtkRenderer;
import vtk.vtkRenderWindowInteractor;

public class BackgroundGradient
{
  // -----------------------------------------------------------------
  // Load VTK library and print which library was not properly loaded
  static 
  {
    if (!vtkNativeLibrary.LoadAllNativeLibraries()) 
    {
      for (vtkNativeLibrary lib : vtkNativeLibrary.values()) 
      {
    if (!lib.IsLoaded()) 
    {
      System.out.println(lib.GetLibraryName() + " not loaded");
    }
       }
      }
      vtkNativeLibrary.DisableOutputWindow(null);
     }
     // -----------------------------------------------------------------   

     public static void main(String args[]) 
     {
       vtkNamedColors colors = new vtkNamedColors();

       //For Actor Color
       double actorColor[] = new double[4];

       //Renderer Background Color
       double Bgcolor[] = new double[4];

       //Renderer Background Color
       double Bgcolor_2[] = new double[4];

       colors.GetColor("MediumSpringGreen", actorColor);
       colors.GetColor("Banana", Bgcolor);
       colors.GetColor("Tomato", Bgcolor_2);

       //Create a Sphere
       vtkSphereSource Sphere = new vtkSphereSource();
       Sphere.Update();

       //Create a Mapper and Actor
       vtkPolyDataMapper Mapper = new vtkPolyDataMapper();
       Mapper.SetInputConnection(Sphere.GetOutputPort());

       vtkActor Actor = new vtkActor();
       Actor.SetMapper(Mapper);
       Actor.GetProperty().SetColor(actorColor);


       // Create the renderer, render window and interactor.
       vtkRenderer ren = new vtkRenderer();
       vtkRenderWindow renWin = new vtkRenderWindow();
       renWin.AddRenderer(ren);
       vtkRenderWindowInteractor iren = new vtkRenderWindowInteractor();
       iren.SetRenderWindow(renWin);

       // Visualise the arrow
       ren.AddActor(Actor);

       //Setting up the background gradient
       ren.GradientBackgroundOn();
       ren.SetBackground(Bgcolor);
       ren.SetBackground2(Bgcolor_2);

       renWin.SetSize(300, 300);
       renWin.Render();

       iren.Initialize();
       iren.Start();
     }  
}