/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkCyclicReferences.cxx,v $
  Language:  C++
  Date:      $Date: 2003/09/10 14:30:06 $
  Version:   $Revision: 1.23 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/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 notices for more information.

=========================================================================*/
#if defined(_MSC_VER)
#pragma warning ( disable : 4786 )
#endif
#include <iostream>
#include "itkImage.h"
#include "itkRandomImageSource.h"
#include "itkShrinkImageFilter.h"
#include "itkCommand.h"
#include "itkTextOutput.h"


// The following class is used to support callbacks
// on the shrink filter in the pipeline that follows later.
class DeleteEvent
{
public:
  void Delete(const itk::Object *caller, const itk::EventObject &) 
    {std::cout << "Deleting: " << caller->GetNameOfClass() << std::endl;}
};

// Note about scoping: Lots of blocks are created here to force the order
// of deletion of objects to insure that the output is in the correct order.
// (Deletion of the smart pointers occurs automatically as scope is exited.)
//
int itkCyclicReferences(int, char* [] )
{
  // Comment the following if you want to use the itk text output window
  itk::OutputWindow::SetInstance( itk::TextOutput::New() );

  // Uncomment the following if you want to see each message independently
  // itk::OutputWindow::GetInstance()->PromptUserOn();

  // Begin by creating a simple pipeline. Use a scalar as a pixel.
  //
  // Create a typedef to make the code more digestable
  typedef itk::Image<float,2> FloatImage2DType;

  // Test the deletion of an image with native type.
  // (scope operators cause automatic smart pointer destruction)
  {//image
  itk::Image<float,2>::Pointer if2 = itk::Image<float,2>::New();
  DeleteEvent deleteEvent;
  itk::MemberCommand<DeleteEvent>::Pointer deleteCommand;
  deleteCommand = itk::MemberCommand<DeleteEvent>::New();
  deleteCommand->SetCallbackFunction(&deleteEvent, &DeleteEvent::Delete);
  if2->AddObserver(itk::DeleteEvent(), deleteCommand);

  //test unregister from vector of data objects
  {
  std::vector<itk::DataObject::Pointer> v;
  v.push_back(if2.GetPointer());
  }
  }//image

  // Create another source object (in this case a random image generator).
  // The source object is templated on the output type.
  //
  {//random
  itk::RandomImageSource<FloatImage2DType>::Pointer random;
  random = itk::RandomImageSource<FloatImage2DType>::New();
  random->SetMin(0.0);
  random->SetMax(1.0);
  DeleteEvent deleteRandom;
  itk::MemberCommand<DeleteEvent>::Pointer deleteRandomCommand;
  deleteRandomCommand = itk::MemberCommand<DeleteEvent>::New();
  deleteRandomCommand->SetCallbackFunction(&deleteRandom, &DeleteEvent::Delete);
  random->AddObserver(itk::DeleteEvent(), deleteRandomCommand);

  // Create a filter...shrink the image by an integral amount. We also 
  // add some callbacks to the start, progress, and end filter execution
  // methods. The filter is templated on the input and output data types.
  //
  {//shrink
  itk::ShrinkImageFilter<FloatImage2DType,FloatImage2DType>::Pointer shrink;
  shrink = itk::ShrinkImageFilter<FloatImage2DType,FloatImage2DType>::New();
  shrink->SetInput(random->GetOutput());
  shrink->SetShrinkFactors(2);
  DeleteEvent deleteShrink;
  itk::MemberCommand<DeleteEvent>::Pointer deleteShrinkCommand;
  deleteShrinkCommand = itk::MemberCommand<DeleteEvent>::New();
  deleteShrinkCommand->SetCallbackFunction(&deleteShrink, &DeleteEvent::Delete);
  shrink->AddObserver(itk::DeleteEvent(), deleteShrinkCommand);
  }//shrink

  }//random
  
  return EXIT_SUCCESS;
}
