text: """this is python equivalent of ./Wrapping/Tcl/vtktesting/backdrop.tcl
  This script is used while running python tests translated from Tcl."""
  
  import vtk
  
  basePlane = None
  baseMapper = None
  base = None
  
  backPlane = None
  backMapper = None
  back = None
  
  leftPlane = None
  leftMapper = None
  left = None
  
  def BuildBackdrop (minX, maxX, minY, maxY, minZ, maxZ, thickness):
      global basePlane
      global baseMapper
      global base
      global backPlane
      global backMapper
      global back
      global left
      global leftPlane
      global leftMapper
      
      if not basePlane:
          basePlane = vtk.vtkCubeSource()
      basePlane.SetCenter( (maxX + minX)/2.0, minY, (maxZ + minZ)/2.0)
      basePlane.SetXLength(maxX-minX)
      basePlane.SetYLength(thickness)
      basePlane.SetZLength(maxZ - minZ)
  
      if not baseMapper:
          baseMapper = vtk.vtkPolyDataMapper()
      baseMapper.SetInput(basePlane.GetOutput())
  
      if not base:
          base = vtk.vtkActor()
      base.SetMapper(baseMapper)
  
      if not backPlane:
          backPlane = vtk.vtkCubeSource()
      backPlane.SetCenter( (maxX + minX)/2.0, (maxY + minY)/2.0, minZ)
      backPlane.SetXLength(maxX-minX)
      backPlane.SetYLength(maxY - minY)
      backPlane.SetZLength(thickness)
  
      if not backMapper:
          backMapper = vtk.vtkPolyDataMapper()
      backMapper.SetInput(backPlane.GetOutput())
  
      if not back:
          back = vtk.vtkActor()
      back.SetMapper(backMapper)
  
      if not leftPlane:
          leftPlane = vtk.vtkCubeSource()
      leftPlane.SetCenter( minX, (maxY+minY)/2.0, (maxZ+minZ)/2.0)
      leftPlane.SetXLength(thickness)
      leftPlane.SetYLength(maxY-minY)
      leftPlane.SetZLength(maxZ-minZ)
  
      if not leftMapper:
          leftMapper = vtk.vtkPolyDataMapper()
      leftMapper.SetInput(leftPlane.GetOutput())
  
      if not left:
          left = vtk.vtkActor()
      left.SetMapper(leftMapper)
  
      return [base, back, left] 
  
  