WikiExamples/Iterators/ShapedNeighborhoodIteratorManual.cxx

#include "itkImage.h"
#include "itkShapedNeighborhoodIterator.h"
#include "itkImageRegionIterator.h"
#include "itkNeighborhoodAlgorithm.h"
 
// Notice that char type pixel values will not appear 
// properly on the command prompt therefore for the 
// demonstration purposes it is best to use the int 
// type, however in real applications iterators have 
// no problems with char type images.
//using ImageType = itk::Image<unsigned char, 2>;
using ImageType = itk::Image<unsigned int, 2>;
 
void CreateImage(ImageType::Pointer image);
 
int main(int, char*[])
{
  ImageType::Pointer image = ImageType::New();
  CreateImage(image);
 
  using IteratorType = itk::ShapedNeighborhoodIterator<ImageType>;

  itk::Size<2> radius;
  radius.Fill(1);
  IteratorType iterator(radius, image, image->GetLargestPossibleRegion());
  std::cout << "By default there are " << iterator.GetActiveIndexListSize() << " active indices." << std::endl;
  
  IteratorType::OffsetType top = {{0,-1}};
  iterator.ActivateOffset(top);
  IteratorType::OffsetType bottom = {{0,1}};
  iterator.ActivateOffset(bottom);
  
  std::cout << "Now there are " << iterator.GetActiveIndexListSize() << " active indices." << std::endl;
  
  IteratorType::IndexListType indexList = iterator.GetActiveIndexList();
  IteratorType::IndexListType::const_iterator listIterator = indexList.begin();
  while (listIterator != indexList.end())
    {
    std::cout << *listIterator << " ";
    ++listIterator;
    }
  std::cout << std::endl;
  
  // Note that ZeroFluxNeumannBoundaryCondition is used by default so even
  // pixels outside of the image will have valid values (equivalent to their neighbors just inside the image)
  for(iterator.GoToBegin(); !iterator.IsAtEnd(); ++iterator)
    {
    std::cout << "New position: " << std::endl;
    IteratorType::ConstIterator ci = iterator.Begin();

    while (! ci.IsAtEnd())
      {
      std::cout << "Centered at " << iterator.GetIndex() << std::endl;
      std::cout << "Neighborhood index " << ci.GetNeighborhoodIndex()
    << " is offset " << ci.GetNeighborhoodOffset()
    << " and has value " << ci.Get()
    << " The real index is " << iterator.GetIndex() + ci.GetNeighborhoodOffset() << std::endl;
      ci++;
      }
    }
    
  std::cout << std::endl;
    
  return EXIT_SUCCESS;
}
 
void CreateImage(ImageType::Pointer image)
{
  ImageType::IndexType start;
  start.Fill(0);
 
  ImageType::SizeType size;
  size.Fill(10);
  
  ImageType::RegionType region(start,size);

  image->SetRegions(region);
  image->Allocate();
  image->FillBuffer(0);
 
}