SphinxExamples/src/Filtering/LabelMap/ExtractGivenLabelObject/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
 *
 *         http://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 "itkImageFileReader.h"
#include "itkImageFileWriter.h"
#include "itkLabelObject.h"
#include "itkLabelMap.h"
#include "itkLabelImageToLabelMapFilter.h"
#include "itkLabelMapToLabelImageFilter.h"
#include "itkLabelSelectionLabelMapFilter.h"
 
int
main(int argc, char * argv[])
{
  if (argc != 5)
  {
    std::cerr << "Usage: " << std::endl;
    std::cerr << argv[0];
    std::cerr << " <InputFileName> <OutputFileName1> <OutputFileName2> <Label>";
    std::cerr << std::endl;
    return EXIT_FAILURE;
  }
 
  constexpr unsigned int Dimension = 2;
 
  using PixelType = unsigned char;
  using ImageType = itk::Image<PixelType, Dimension>;
 
  const char * inputFileName = argv[1];
  const char * outputFileName[2];
  outputFileName[0] = argv[2];
  outputFileName[1] = argv[3];
  const auto label = static_cast<PixelType>(std::stoi(argv[4]));
 
  using ReaderType = itk::ImageFileReader<ImageType>;
  ReaderType::Pointer reader = ReaderType::New();
  reader->SetFileName(inputFileName);
 
  using LabelObjectType = itk::LabelObject<PixelType, Dimension>;
  using LabelMapType = itk::LabelMap<LabelObjectType>;
 
  using LabelImageToLabelMapFilterType = itk::LabelImageToLabelMapFilter<ImageType, LabelMapType>;
  LabelImageToLabelMapFilterType::Pointer labelMapConverter = LabelImageToLabelMapFilterType::New();
  labelMapConverter->SetInput(reader->GetOutput());
  labelMapConverter->SetBackgroundValue(itk::NumericTraits<PixelType>::Zero);
 
  using SelectorType = itk::LabelSelectionLabelMapFilter<LabelMapType>;
  SelectorType::Pointer selector = SelectorType::New();
  selector->SetInput(labelMapConverter->GetOutput());
  selector->SetLabel(label);
 
  for (int i = 0; i < 2; i++)
  {
    using LabelMapToLabelImageFilterType = itk::LabelMapToLabelImageFilter<LabelMapType, ImageType>;
    LabelMapToLabelImageFilterType::Pointer labelImageConverter = LabelMapToLabelImageFilterType::New();
    labelImageConverter->SetInput(selector->GetOutput(i));
 
    using WriterType = itk::ImageFileWriter<ImageType>;
    WriterType::Pointer writer = WriterType::New();
    writer->SetFileName(outputFileName[i]);
    writer->SetInput(labelImageConverter->GetOutput());
    try
    {
      writer->Update();
    }
    catch (itk::ExceptionObject & error)
    {
      std::cerr << "Error: " << error << std::endl;
      return EXIT_FAILURE;
    }
  }
 
  return EXIT_SUCCESS;
}