/*=========================================================================
 *
 *  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.
 *
 *=========================================================================*/
#ifndef itkBinaryMedianImageFilter_h
#define itkBinaryMedianImageFilter_h

#include "itkImageToImageFilter.h"

namespace itk
{
/**
 * \class BinaryMedianImageFilter
 * \brief Applies a version of the median filter optimized for binary images.
 *
 * This filter was contributed by Bjorn Hanch Sollie after identifying that
 * the generic Median filter performed unnecessary operations when the input
 * image is binary.
 *
 * This filter computes an image where a given pixel is the median value
 * of the pixels in a neighborhood about the corresponding input pixel.
 * For the case of binary images the median can be obtained by simply counting
 * the neighbors that are foreground.
 *
 * A median filter is one of the family of nonlinear filters.  It is
 * used to smooth an image without being biased by outliers or shot noise.
 *
 * \sa Image
 * \sa Neighborhood
 * \sa NeighborhoodOperator
 * \sa NeighborhoodIterator
 *
 * \ingroup IntensityImageFilters
 * \ingroup ITKLabelVoting
 */
template <typename TInputImage, typename TOutputImage>
class ITK_TEMPLATE_EXPORT BinaryMedianImageFilter : public ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(BinaryMedianImageFilter);

  /** Extract dimension from input and output image. */
  static constexpr unsigned int InputImageDimension = TInputImage::ImageDimension;
  static constexpr unsigned int OutputImageDimension = TOutputImage::ImageDimension;

  /** Convenient type alias for simplifying declarations. */
  using InputImageType = TInputImage;
  using OutputImageType = TOutputImage;

  /** Standard class type aliases. */
  using Self = BinaryMedianImageFilter;
  using Superclass = ImageToImageFilter<InputImageType, OutputImageType>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  /** Method for creation through the object factory. */
  itkNewMacro(Self);

  /** \see LightObject::GetNameOfClass() */
  itkOverrideGetNameOfClassMacro(BinaryMedianImageFilter);

  /** Image type alias support */
  using InputPixelType = typename InputImageType::PixelType;
  using OutputPixelType = typename OutputImageType::PixelType;

  using InputImageRegionType = typename InputImageType::RegionType;
  using OutputImageRegionType = typename OutputImageType::RegionType;

  using InputSizeType = typename InputImageType::SizeType;

  /** Set the radius of the neighborhood used to compute the median. */
  itkSetMacro(Radius, InputSizeType);

  /** Get the radius of the neighborhood used to compute the median */
  itkGetConstReferenceMacro(Radius, InputSizeType);

  /** Set the value associated with the Foreground (or the object) on
      the binary input image and the Background . */
  itkSetMacro(BackgroundValue, InputPixelType);
  itkSetMacro(ForegroundValue, InputPixelType);

  /** Get the value associated with the Foreground (or the object) on the
      binary input image and the Background . */
  itkGetConstReferenceMacro(BackgroundValue, InputPixelType);
  itkGetConstReferenceMacro(ForegroundValue, InputPixelType);

  /** BinaryMedianImageFilter needs a larger input requested region than
   * the output requested region.  As such, BinaryMedianImageFilter needs
   * to provide an implementation for GenerateInputRequestedRegion()
   * in order to inform the pipeline execution model.
   *
   * \sa ImageToImageFilter::GenerateInputRequestedRegion() */
  void
  GenerateInputRequestedRegion() override;

#ifdef ITK_USE_CONCEPT_CHECKING
  // Begin concept checking
  itkConceptMacro(InputEqualityComparableCheck, (Concept::EqualityComparable<typename TInputImage::PixelType>));
  itkConceptMacro(InputConvertibleToOutputCheck,
                  (Concept::Convertible<typename TInputImage::PixelType, typename TOutputImage::PixelType>));
  itkConceptMacro(SameDimensionCheck, (Concept::SameDimension<InputImageDimension, OutputImageDimension>));
  itkConceptMacro(InputOStreamWritableCheck, (Concept::OStreamWritable<typename TInputImage::PixelType>));
  // End concept checking
#endif

protected:
  BinaryMedianImageFilter();
  ~BinaryMedianImageFilter() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  /** BinaryMedianImageFilter can be implemented as a multithreaded filter.
   * Therefore, this implementation provides a DynamicThreadedGenerateData()
   * routine which is called for each processing thread. The output
   * image data is allocated automatically by the superclass prior to
   * calling DynamicThreadedGenerateData().  DynamicThreadedGenerateData can only
   * write to the portion of the output image specified by the
   * parameter "outputRegionForThread"
   *
   * \sa ImageToImageFilter::ThreadedGenerateData(),
   *     ImageToImageFilter::GenerateData() */
  void
  DynamicThreadedGenerateData(const OutputImageRegionType & outputRegionForThread) override;


private:
  InputSizeType m_Radius{};

  InputPixelType m_ForegroundValue{};
  InputPixelType m_BackgroundValue{};
};
} // end namespace itk

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

#endif
