rtkForwardDifferenceGradientImageFilter.h

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/*=========================================================================
 *
 *  Copyright RTK Consortium
 *
 *  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.
 *
 *=========================================================================*/

#ifndef rtkForwardDifferenceGradientImageFilter_h
#define rtkForwardDifferenceGradientImageFilter_h

#include <itkImageToImageFilter.h>
#include <itkCovariantVector.h>
#include <itkImageRegionIterator.h>

#include "rtkMacro.h"

namespace rtk
{
template <typename TInputImage,
          typename TOperatorValueType = float,
          typename TOuputValue = float,
          typename TOuputImage =
            itk::Image<itk::CovariantVector<TOuputValue, TInputImage::ImageDimension>, TInputImage::ImageDimension>>
class ITK_TEMPLATE_EXPORT ForwardDifferenceGradientImageFilter
  : public itk::ImageToImageFilter<TInputImage, TOuputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ForwardDifferenceGradientImageFilter);

  static constexpr unsigned int InputImageDimension = TInputImage::ImageDimension;
  static constexpr unsigned int OutputImageDimension = TOuputImage::ImageDimension;

  using Self = ForwardDifferenceGradientImageFilter;

  using InputImageType = TInputImage;
  using InputImagePointer = typename InputImageType::Pointer;
  using OutputImageType = TOuputImage;
  using OutputImagePointer = typename OutputImageType::Pointer;

  using Superclass = itk::ImageToImageFilter<InputImageType, OutputImageType>;
  using Pointer = itk::SmartPointer<Self>;
  using ConstPointer = itk::SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(ForwardDifferenceGradientImageFilter);

  using OperatorValueType = TOperatorValueType;
  using OutputValueType = TOuputValue;
  using InputPixelType = typename InputImageType::PixelType;
  using CovariantVectorType = typename OutputImageType::PixelType;
  using OutputImageRegionType = typename OutputImageType::RegionType;

  void
  GenerateInputRequestedRegion() override;

  void
  SetUseImageSpacingOn()
  {
    this->SetUseImageSpacing(true);
  }

  void
  SetUseImageSpacingOff()
  {
    this->SetUseImageSpacing(false);
  }

  itkSetMacro(UseImageSpacing, bool);
  itkGetConstMacro(UseImageSpacing, bool);

  void
  SetDimensionsProcessed(bool * DimensionsProcessed);

  void
  OverrideBoundaryCondition(itk::ImageBoundaryCondition<TInputImage> * boundaryCondition);

  // Begin concept checking
  itkConceptMacro(InputConvertibleToOutputCheck, (itk::Concept::Convertible<InputPixelType, OutputValueType>));
  itkConceptMacro(OutputHasNumericTraitsCheck, (itk::Concept::HasNumericTraits<OutputValueType>));
  // End concept checking

  itkSetMacro(UseImageDirection, bool);
  itkGetConstMacro(UseImageDirection, bool);
  itkBooleanMacro(UseImageDirection);

protected:
  ForwardDifferenceGradientImageFilter();
  ~ForwardDifferenceGradientImageFilter() override;
  void
  PrintSelf(std::ostream & os, itk::Indent indent) const override;

  void
  DynamicThreadedGenerateData(const OutputImageRegionType & outputRegionForThread) override;

  void
  GenerateOutputInformation() override;

private:
  //  // An overloaded method which may transform the gradient to a
  //  // physical vector and converts to the correct output pixel type.
  //  template <typename TValue>
  //  void SetOutputPixel( ImageRegionIterator< VectorImage<TValue,OutputImageDimension> > &it, CovariantVectorType
  //  &gradient )
  //  {
  //    if ( this->m_UseImageDirection )
  //      {
  //      CovariantVectorType physicalGradient;
  //      it.GetImage()->TransformLocalVectorToPhysicalVector( gradient, physicalGradient );
  //      it.Set( OutputPixelType( physicalGradient.GetDataPointer(), InputImageDimension, false ) );
  //      }
  //    else
  //      {
  //      it.Set( OutputPixelType( gradient.GetDataPointer(), InputImageDimension, false ) );
  //      }
  //  }

  template <typename T>
  void
  SetOutputPixel(itk::ImageRegionIterator<T> & it, CovariantVectorType & gradient)
  {
    it.Value() = gradient;
  }


  bool m_UseImageSpacing;

  // flag to take or not the image direction into account
  // when computing the derivatives.
  bool m_UseImageDirection;

  // list of the dimensions along which the gradient has
  // to be computed. The components on other dimensions
  // are set to zero
  bool m_DimensionsProcessed[TInputImage::ImageDimension];

  itk::ImageBoundaryCondition<TInputImage, TInputImage> * m_BoundaryCondition;
  bool                                                    m_IsBoundaryConditionOverriden;
};
} // namespace rtk

#ifndef ITK_MANUAL_INSTANTIATION
#  include "rtkForwardDifferenceGradientImageFilter.hxx"
#endif

#endif