text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    GraphItem.cxx
  
    Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
    All rights reserved.
    See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
  
       This software is distributed WITHOUT ANY WARRANTY; without even
       the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
       PURPOSE.  See the above copyright notice for more information.
  
  =========================================================================*/
  
  #include "vtkRenderer.h"
  #include "vtkRenderWindow.h"
  #include "vtkRenderWindowInteractor.h"
  #include "vtkSmartPointer.h"
  #include "vtkContextView.h"
  #include "vtkContextScene.h"
  #include "vtkPiecewiseFunctionItem.h"
  #include "vtkPiecewiseControlPointsItem.h"
  #include "vtkPiecewiseFunction.h"
  
  //----------------------------------------------------------------------------
  int main(int, char *[])
  {
    // Set up a 2D context view, context test object and add it to the scene
    vtkSmartPointer<vtkContextView> view = vtkSmartPointer<vtkContextView>::New();
    view->GetRenderer()->SetBackground(1.0, 1.0, 1.0);
    view->GetRenderWindow()->SetSize(800, 600);
    view->GetRenderWindow()->SetMultiSamples(0);
  
    vtkSmartPointer<vtkPiecewiseFunction> source = vtkSmartPointer<vtkPiecewiseFunction>::New();
    source->AddPoint(0,0);
    source->AddPoint(200,200);
    source->AddPoint(400,500);
    source->AddPoint(700,500);
  //   source->Update();
    vtkSmartPointer<vtkPiecewiseControlPointsItem> item = vtkSmartPointer<vtkPiecewiseControlPointsItem>::New();
    item->SetPiecewiseFunction(source);
    view->GetScene()->AddItem(item);
  
    // NOT WORKING...
    //vtkSmartPointer<vtkPiecewiseFunctionItem> item2 = vtkSmartPointer<vtkPiecewiseFunctionItem>::New();
    //item2->SetPiecewiseFunction(source);
    //view->GetScene()->AddItem(item2);
  
    view->GetRenderWindow()->GetInteractor()->Initialize();
    view->GetRenderWindow()->GetInteractor()->CreateOneShotTimer(10);
  
    view->GetRenderWindow()->GetInteractor()->Start();
  }
  