SphinxExamples/src/Core/Common/ApplyCustomOperationToEachPixelInImage/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 "itkVectorImage.h"
#include "itkVector.h"
#include "itkVariableLengthVector.h"
#include "itkRigid2DTransform.h"
#include "itkUnaryFunctorImageFilter.h"
#include "itkMath.h"
 
template <class TInput, class TOutput>
class RotateVectors
{
public:
  RotateVectors() = default;
  ~RotateVectors() = default;
  bool
  operator!=(const RotateVectors &) const
  {
    return false;
  }
  bool
  operator==(const RotateVectors & other) const
  {
    return !(*this != other);
  }
  inline TOutput
  operator()(const TInput & A) const
  {
    using VectorType = itk::Vector<float, 2>;
    VectorType v;
    v[0] = A[0];
    v[1] = A[1];
 
    using TransformType = itk::Rigid2DTransform<float>;
 
    auto transform = TransformType::New();
    transform->SetAngle(itk::Math::pi / 2.0);
 
    VectorType outputV = transform->TransformVector(v);
    TOutput    transformedVector;
    transformedVector.SetSize(2);
    transformedVector[0] = outputV[0];
    transformedVector[1] = outputV[1];
 
    return transformedVector;
  }
};
 
int
main()
{
  using ImageType = itk::VectorImage<float, 2>;
 
  ImageType::RegionType region;
  ImageType::IndexType  start;
  start[0] = 0;
  start[1] = 0;
 
  ImageType::SizeType size;
  size[0] = 2;
  size[1] = 3;
 
  region.SetSize(size);
  region.SetIndex(start);
 
  auto image = ImageType::New();
  image->SetRegions(region);
  image->SetVectorLength(2);
  image->Allocate();
 
  ImageType::IndexType pixelIndex;
  pixelIndex[0] = 1;
  pixelIndex[1] = 1;
 
  using VectorType = itk::VariableLengthVector<float>;
  VectorType v;
  v.SetSize(2);
  v[0] = 1;
  v[1] = 0;
 
  image->SetPixel(pixelIndex, v);
 
  using FilterType =
    itk::UnaryFunctorImageFilter<ImageType, ImageType, RotateVectors<ImageType::PixelType, ImageType::PixelType>>;
 
  auto filter = FilterType::New();
  filter->SetInput(image);
  filter->Update();
 
  ImageType::PixelType inputPixelValue = image->GetPixel(pixelIndex);
  ImageType::PixelType outputPixelValue = filter->GetOutput()->GetPixel(pixelIndex);
 
  std::cout << "pixel (1,1) was = " << inputPixelValue << std::endl;
  std::cout << "pixel (1,1) now = " << outputPixelValue << std::endl;
 
  return EXIT_SUCCESS;
}