text: #!/usr/bin/env python
  
  # This example demonstrates the use of 2D text.
  
  import vtk
  
  # Create a sphere source, mapper, and actor
  sphere = vtk.vtkSphereSource()
  
  sphereMapper = vtk.vtkPolyDataMapper()
  sphereMapper.SetInputConnection(sphere.GetOutputPort())
  sphereActor = vtk.vtkLODActor()
  sphereActor.SetMapper(sphereMapper)
  
  # Create a scaled text actor.
  # Set the text, font, justification, and properties (bold, italics,
  # etc.).
  textActor = vtk.vtkTextActor()
  textActor.SetTextScaleModeToProp()
  textActor.SetDisplayPosition(90, 50)
  textActor.SetInput("This is a sphere")
  
  # Set coordinates to match the old vtkScaledTextActor default value
  textActor.GetPosition2Coordinate().SetCoordinateSystemToNormalizedViewport()
  textActor.GetPosition2Coordinate().SetValue(0.6, 0.1)
  
  tprop = textActor.GetTextProperty()
  tprop.SetFontSize(18)
  tprop.SetFontFamilyToArial()
  tprop.SetJustificationToCentered()
  tprop.BoldOn()
  tprop.ItalicOn()
  tprop.ShadowOn()
  tprop.SetColor(0, 0, 1)
  
  # Create the Renderer, RenderWindow, RenderWindowInteractor
  ren = vtk.vtkRenderer()
  renWin = vtk.vtkRenderWindow()
  renWin.AddRenderer(ren)
  iren = vtk.vtkRenderWindowInteractor()
  iren.SetRenderWindow(renWin)
  
  # Add the actors to the renderer; set the background and size; zoom
  # in; and render.
  ren.AddActor2D(textActor)
  ren.AddActor(sphereActor)
  
  ren.SetBackground(1, 1, 1)
  renWin.SetSize(250, 125)
  ren.ResetCamera()
  ren.GetActiveCamera().Zoom(1.5)
  
  iren.Initialize()
  renWin.Render()
  iren.Start()
  