SphinxExamples/src/Filtering/ImageIntensity/SubtractConstantFromEveryPixel/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 "itkSubtractImageFilter.h"
#include "itkImageFileWriter.h"
 
using ImageType = itk::Image<unsigned char, 2>;
static void
CreateImage(ImageType::Pointer image);
 
int
main()
{
  auto image = ImageType::New();
  CreateImage(image);
 
  using SubtractImageFilterType = itk::SubtractImageFilter<ImageType, ImageType, ImageType>;
  auto subtractConstantFromImageFilter = SubtractImageFilterType::New();
  subtractConstantFromImageFilter->SetInput(image);
  subtractConstantFromImageFilter->SetConstant2(2);
  subtractConstantFromImageFilter->Update();
 
  itk::WriteImage(subtractConstantFromImageFilter->GetOutput(), "output.png");
 
  return EXIT_SUCCESS;
}
 
void
CreateImage(ImageType::Pointer image)
{
  ImageType::IndexType start;
  start.Fill(0);
 
  ImageType::SizeType size;
  size.Fill(100);
 
  ImageType::RegionType region;
  region.SetSize(size);
  region.SetIndex(start);
 
  image->SetRegions(region);
  image->Allocate();
 
  itk::ImageRegionIterator<ImageType> imageIterator(image, region);
 
  while (!imageIterator.IsAtEnd())
  {
    if (imageIterator.GetIndex()[0] < 70)
    {
      imageIterator.Set(255);
    }
    else
    {
      imageIterator.Set(0);
    }
 
    ++imageIterator;
  }
}