itkImageGridSampler.h

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/*=========================================================================
 *
 *  Copyright UMC Utrecht and contributors
 *
 *  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
 *
 *        http://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 itkImageGridSampler_h
#define itkImageGridSampler_h
 
#include "itkImageSamplerBase.h"
#include "elxMaskHasSameImageDomain.h"
 
namespace itk
{

 
template <typename TInputImage>
class ITK_TEMPLATE_EXPORT ImageGridSampler : public ImageSamplerBase<TInputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ImageGridSampler);

  using Self = ImageGridSampler;
  using Superclass = ImageSamplerBase<TInputImage>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  itkNewMacro(Self);

  itkOverrideGetNameOfClassMacro(ImageGridSampler);

  using typename Superclass::DataObjectPointer;
  using typename Superclass::OutputVectorContainerType;
  using typename Superclass::OutputVectorContainerPointer;
  using typename Superclass::InputImageType;
  using typename Superclass::InputImagePointer;
  using typename Superclass::InputImageConstPointer;
  using typename Superclass::InputImageRegionType;
  using typename Superclass::InputImagePixelType;
  using typename Superclass::ImageSampleType;
  using typename Superclass::ImageSampleContainerType;
  using typename Superclass::ImageSampleContainerPointer;
 
  // Clang/macos-12/Xcode_14.2 does not like `using typename Superclass::MaskType`, saying "error: 'MaskType' is not a
  // class, namespace, or enumeration"
  using MaskType = typename Superclass::MaskType;

  itkStaticConstMacro(InputImageDimension, unsigned int, Superclass::InputImageDimension);

  using typename Superclass::InputImageIndexType;
  // using typename Superclass::InputImageSpacingType;
  using typename Superclass::InputImagePointType;

  using SampleGridSpacingType = typename InputImageType::OffsetType;
  using SampleGridSpacingValueType = typename SampleGridSpacingType::OffsetValueType;
  using SampleGridSizeType = typename InputImageType::SizeType;
  using SampleGridIndexType = InputImageIndexType;
  using InputImageSizeType = typename InputImageType::SizeType;

  void
  SetSampleGridSpacing(const SampleGridSpacingType & arg);
 
  itkGetConstReferenceMacro(SampleGridSpacing, SampleGridSpacingType);

  void
  SetNumberOfSamples(unsigned long nrofsamples) override;

  bool
  SelectNewSamplesOnUpdate() override
  {
    return false;
  }
 

  bool
  SelectingNewSamplesOnUpdateSupported() const override
  {
    return false;
  }
 
 
protected:
  ImageGridSampler() = default;

  ~ImageGridSampler() override = default;

  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  void
  GenerateData() override;
 
private:
  struct WorkUnit
  {
    const SampleGridIndexType GridIndex{};
    const SampleGridSizeType  GridSize{};
 
    // Should point to the first sample for this specific work unit.
    ImageSampleType * const Samples{};
 
    // The number of samples retrieved by this work unit. Only used when a mask is specified.
    size_t NumberOfSamples{};
  };
 
  struct UserData
  {
    const InputImageType &      InputImage;
    const MaskType * const      Mask{};
    const SampleGridSpacingType GridSpacing{};
    std::vector<WorkUnit>       WorkUnits{};
  };
 
  template <elastix::MaskCondition VMaskCondition>
  static ITK_THREAD_RETURN_FUNCTION_CALL_CONVENTION
  ThreaderCallback(void * arg);

  template <unsigned int VIndex>
  static unsigned int
  GetGridSizeValue(const SampleGridSizeType & gridSize)
  {
    if constexpr (VIndex < InputImageDimension)
    {
      return gridSize[VIndex];
    }
    else
    {
      return 1;
    }
  }

  template <unsigned int VIndex>
  static void
  JumpToNextGridPosition(SampleGridIndexType &         index,
                         const SampleGridIndexType &   gridIndex,
                         const SampleGridSpacingType & gridSpacing)
  {
    static_assert(VIndex > 0);
 
    if constexpr (VIndex < InputImageDimension)
    {
      index[VIndex - 1] = gridIndex[VIndex - 1];
      index[VIndex] += gridSpacing[VIndex];
    }
  }
 

  static std::pair<SampleGridIndexType, SampleGridSizeType>
  DetermineGridIndexAndSize(const InputImageRegionType &  croppedInputImageRegion,
                            const SampleGridSpacingType & gridSpacing);

  static std::vector<WorkUnit>
  GenerateWorkUnits(const ThreadIdType             numberOfWorkUnits,
                    const InputImageRegionType &   croppedInputImageRegion,
                    const SampleGridIndexType      gridIndex,
                    const SampleGridSpacingType    gridSpacing,
                    std::vector<ImageSampleType> & samples);
 
  static void
  SingleThreadedGenerateData(const TInputImage &            inputImage,
                             const MaskType * const         mask,
                             const InputImageRegionType &   croppedInputImageRegion,
                             const SampleGridSpacingType &  gridSpacing,
                             std::vector<ImageSampleType> & samples);
  static void
  MultiThreadedGenerateData(MultiThreaderBase &            multiThreader,
                            const ThreadIdType             numberOfWorkUnits,
                            const TInputImage &            inputImage,
                            const MaskType * const         mask,
                            const InputImageRegionType &   croppedInputImageRegion,
                            const SampleGridSpacingType &  gridSpacing,
                            std::vector<ImageSampleType> & samples);

  template <elastix::MaskCondition VMaskCondition>
  static void
  GenerateDataForWorkUnit(WorkUnit &, const InputImageType &, const MaskType *, const SampleGridSpacingType &);

  SampleGridSpacingType m_SampleGridSpacing{ itk::MakeFilled<SampleGridSpacingType>(1) };

  unsigned long m_RequestedNumberOfSamples{ 0 };
};
 
} // end namespace itk
 
#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkImageGridSampler.hxx"
#endif
 
#endif // end #ifndef itkImageGridSampler_h