old_contents: #!/usr/bin/env python
  import vtk
  
  def main():
      colors = vtk.vtkNamedColors()
  
      # Create a circle
      polygonSource = vtk.vtkRegularPolygonSource()
      # Uncomment this line to generate only the outline of the circle.
      # polygonSource.GeneratePolygonOff()
      polygonSource.SetNumberOfSides(50);
      polygonSource.SetRadius(5.0)
      polygonSource.SetCenter(0.0, 0.0, 0.0)
      
      #  Visualize
      mapper = vtk.vtkPolyDataMapper()
      mapper.SetInputConnection(polygonSource.GetOutputPort())
  
      actor = vtk.vtkActor()
      actor.SetMapper(mapper)
      actor.GetProperty().SetColor(colors.GetColor3d("Cornsilk"))
  
      renderer = vtk.vtkRenderer()
      renderWindow = vtk.vtkRenderWindow()
      renderWindow.SetWindowName("Circle")
      renderWindow.AddRenderer(renderer)
      renderWindowInteractor = vtk.vtkRenderWindowInteractor()
      renderWindowInteractor.SetRenderWindow(renderWindow)
  
      renderer.AddActor(actor)
      renderer.SetBackground(colors.GetColor3d("DarkGreen"))
  
      renderWindow.Render()
      renderWindowInteractor.Start()
  
  
  if __name__ == '__main__':
      main()
  
new_contents: #!/usr/bin/env python
  import vtk
  
  def main():
      colors = vtk.vtkNamedColors()
  
      # Create a circle
      polygonSource = vtk.vtkRegularPolygonSource()
      # Uncomment this line to generate only the outline of the circle.
      # polygonSource.GeneratePolygonOff()
      polygonSource.SetNumberOfSides(50)
      polygonSource.SetRadius(5.0)
      polygonSource.SetCenter(0.0, 0.0, 0.0)
      
      #  Visualize
      mapper = vtk.vtkPolyDataMapper()
      mapper.SetInputConnection(polygonSource.GetOutputPort())
  
      actor = vtk.vtkActor()
      actor.SetMapper(mapper)
      actor.GetProperty().SetColor(colors.GetColor3d("Cornsilk"))
  
      renderer = vtk.vtkRenderer()
      renderWindow = vtk.vtkRenderWindow()
      renderWindow.SetWindowName("Circle")
      renderWindow.AddRenderer(renderer)
      renderWindowInteractor = vtk.vtkRenderWindowInteractor()
      renderWindowInteractor.SetRenderWindow(renderWindow)
  
      renderer.AddActor(actor)
      renderer.SetBackground(colors.GetColor3d("DarkGreen"))
  
      renderWindow.Render()
      renderWindowInteractor.Start()
  
  
  if __name__ == '__main__':
      main()
  
subject: Update Circle.py