SphinxExamples/src/Core/ImageAdaptors/ExtractChannelOfImageWithMultipleComponents/Code.cxx

/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 *
 *=========================================================================*/
#include "itkImageAdaptor.h"
#include "itkImageRegionIterator.h"
#include "itkNthElementImageAdaptor.h"
 
using VectorImageType = itk::Image<itk::CovariantVector<float, 3>, 2>;
 
static void
CreateImage(VectorImageType::Pointer image);
 
int
main()
{
  auto image = VectorImageType::New();
  CreateImage(image);
 
  itk::Index<2> index{};
 
  std::cout << image->GetPixel(index) << std::endl;
 
  using ImageAdaptorType = itk::NthElementImageAdaptor<VectorImageType, float>;
 
  auto adaptor = ImageAdaptorType::New();
 
  adaptor->SelectNthElement(0);
  adaptor->SetImage(image);
 
  std::cout << adaptor->GetPixel(index) << std::endl;
 
  return EXIT_SUCCESS;
}
 
void
CreateImage(VectorImageType::Pointer image)
{
  VectorImageType::IndexType start{};
 
  auto size = VectorImageType::SizeType::Filled(2);
 
  VectorImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);
 
  image->SetRegions(region);
  image->Allocate();
 
  // Create a pixel and fill it with (1,2,3), and set every pixel of the image to this pixel.
 
  itk::ImageRegionIterator<VectorImageType> imageIterator(image, image->GetLargestPossibleRegion());
  itk::CovariantVector<float, 3>            vectorPixel;
  vectorPixel[0] = 1;
  vectorPixel[1] = 2;
  vectorPixel[2] = 3;
 
  image->FillBuffer(vectorPixel);
}