/*=========================================================================
 *
 *  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 itkMaskedImageToHistogramFilter_h
#define itkMaskedImageToHistogramFilter_h

#include "itkHistogram.h"
#include "itkImageToHistogramFilter.h"
#include "itkSimpleDataObjectDecorator.h"

namespace itk
{
namespace Statistics
{
/**
 * \class MaskedImageToHistogramFilter
 *  \brief Generate a histogram from the masked pixels of an image.
 *
 * This class expands the features of the ImageToHistogramFilter by
 * adding a required MaskImage input image. Only the pixel in the
 * input image where the MaskImage's value is the MaskValue will be
 * added to the computed histogram.
 *
 * \ingroup ITKStatistics
 *
 * \sphinx
 * \sphinxexample{Numerics/Statistics/ComputeHistogramOfMaskedRegion,Compute Histogram Of Masked Region In Image}
 * \endsphinx
 */

template <typename TImage, typename TMaskImage>
class ITK_TEMPLATE_EXPORT MaskedImageToHistogramFilter : public ImageToHistogramFilter<TImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(MaskedImageToHistogramFilter);

  /** Standard type alias */
  using Self = MaskedImageToHistogramFilter;
  using Superclass = ImageToHistogramFilter<TImage>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

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

  /** standard New() method support */
  itkNewMacro(Self);

  using ImageType = TImage;
  using PixelType = typename ImageType::PixelType;
  using RegionType = typename ImageType::RegionType;
  using ValueType = typename NumericTraits<PixelType>::ValueType;
  using ValueRealType = typename NumericTraits<ValueType>::RealType;

  using HistogramType = Histogram<ValueRealType>;
  using HistogramPointer = typename HistogramType::Pointer;
  using HistogramConstPointer = typename HistogramType::ConstPointer;
  using HistogramSizeType = typename HistogramType::SizeType;
  using HistogramMeasurementType = typename HistogramType::MeasurementType;
  using HistogramMeasurementVectorType = typename HistogramType::MeasurementVectorType;

  using MaskImageType = TMaskImage;
  using MaskPixelType = typename MaskImageType::PixelType;

  /** Method to set/get the mask */
  itkSetInputMacro(MaskImage, MaskImageType);
  itkGetInputMacro(MaskImage, MaskImageType);

  /** Set the pixel value treated as on in the mask.
   * Only pixels with this value will be added to the histogram.
   */
  itkSetGetDecoratedInputMacro(MaskValue, MaskPixelType);

protected:
  MaskedImageToHistogramFilter();
  ~MaskedImageToHistogramFilter() override = default;

  void
  ThreadedStreamedGenerateData(const RegionType & inputRegionForThread) override;
  void
  ThreadedComputeMinimumAndMaximum(const RegionType & inputRegionForThread) override;
};
} // end of namespace Statistics
} // end of namespace itk

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

#endif
