SphinxExamples/src/Filtering/LabelMap/ConvertImageWithLabelsToShapeLabelMap/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 "itkImage.h"
#include "itkLabelImageToShapeLabelMapFilter.h"
#include "itkConnectedComponentImageFilter.h"
 
using ImageType = itk::Image<unsigned char, 2>;
 
static void
CreateImage(ImageType::Pointer image);
 
int
main()
{
  auto image = ImageType::New();
  CreateImage(image);
 
  using ConnectedComponentImageFilterType = itk::ConnectedComponentImageFilter<ImageType, ImageType>;
  auto connectedComponentImageFilter = ConnectedComponentImageFilterType::New();
  connectedComponentImageFilter->SetInput(image);
  connectedComponentImageFilter->Update();
 
  using LabelImageToShapeLabelMapFilterType = itk::LabelImageToShapeLabelMapFilter<ImageType>;
  LabelImageToShapeLabelMapFilterType::Pointer labelImageToShapeLabelMapFilter =
    LabelImageToShapeLabelMapFilterType::New();
  labelImageToShapeLabelMapFilter->SetInput(connectedComponentImageFilter->GetOutput());
  labelImageToShapeLabelMapFilter->Update();
 
  // The output of this filter is an itk::LabelMap, which contains itk::LabelObject's
  std::cout << "There are " << labelImageToShapeLabelMapFilter->GetOutput()->GetNumberOfLabelObjects() << " objects."
            << std::endl;
 
  return EXIT_SUCCESS;
}
 
void
CreateImage(ImageType::Pointer image)
{
  // Create an image with 2 connected components
  ImageType::RegionType region;
  ImageType::IndexType  start;
  start[0] = 0;
  start[1] = 0;
 
  ImageType::SizeType size;
  unsigned int        NumRows = 200;
  unsigned int        NumCols = 300;
  size[0] = NumRows;
  size[1] = NumCols;
 
  region.SetSize(size);
  region.SetIndex(start);
 
  image->SetRegions(region);
  image->Allocate();
 
  // Make a square
  for (unsigned int r = 20; r < 80; ++r)
  {
    for (unsigned int c = 30; c < 100; ++c)
    {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;
 
      image->SetPixel(pixelIndex, 255);
    }
  }
 
  // Make another square
  for (unsigned int r = 100; r < 130; ++r)
  {
    for (unsigned int c = 115; c < 160; ++c)
    {
      ImageType::IndexType pixelIndex;
      pixelIndex[0] = r;
      pixelIndex[1] = c;
 
      image->SetPixel(pixelIndex, 255);
    }
  }
}