text: /*=========================================================================
   *
   *  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
   *
   *         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 itkBasicErodeImageFilter_h
  #define itkBasicErodeImageFilter_h
  
  #include "itkMorphologyImageFilter.h"
  
  namespace itk
  {
  /** \class BasicErodeImageFilter
   * \brief gray scale erosion of an image
   *
   * Erode an image using grayscale morphology. Erosion takes the
   * minimum of all the pixels identified by the structuring element.
   *
   * The structuring element is assumed to be composed of binary
   * values (zero or one). Only elements of the structuring element
   * having values > 0 are candidates for affecting the center pixel.
   *
   * For the each input image pixel,
   *   - NeighborhoodIterator gives neighbors of the pixel.
   *   - Evaluate() member function returns the minimum value among
   *     the image neighbors where the kernel has elements > 0
   *   - Replace the original value with the min value
   *
   * \sa MorphologyImageFilter, GrayscaleFunctionErodeImageFilter, BinaryErodeImageFilter
   * \ingroup ImageEnhancement  MathematicalMorphologyImageFilters
   * \ingroup ITKMathematicalMorphology
   */
  template <typename TInputImage, typename TOutputImage, typename TKernel>
  class ITK_TEMPLATE_EXPORT BasicErodeImageFilter : public MorphologyImageFilter<TInputImage, TOutputImage, TKernel>
  {
  public:
    ITK_DISALLOW_COPY_AND_ASSIGN(BasicErodeImageFilter);
  
    /** Standard class type aliases. */
    using Self = BasicErodeImageFilter;
    using Superclass = MorphologyImageFilter<TInputImage, TOutputImage, TKernel>;
    using Pointer = SmartPointer<Self>;
    using ConstPointer = SmartPointer<const Self>;
  
    /** Standard New method. */
    itkNewMacro(Self);
  
    /** Runtime information support. */
    itkTypeMacro(BasicErodeImageFilter, MorphologyImageFilter);
  
    /** Declaration of pixel type. */
    using PixelType = typename Superclass::PixelType;
  
    /** Kernel (structuring element) iterator. */
    using KernelIteratorType = typename Superclass::KernelIteratorType;
  
    /** Neighborhood iterator type. */
    using NeighborhoodIteratorType = typename Superclass::NeighborhoodIteratorType;
  
    /** Kernel type alias. */
    using KernelType = typename Superclass::KernelType;
  
    /** Default boundary condition type */
    using DefaultBoundaryConditionType = typename Superclass::DefaultBoundaryConditionType;
  
    /** ImageDimension constants */
    static constexpr unsigned int InputImageDimension = TInputImage::ImageDimension;
    static constexpr unsigned int OutputImageDimension = TOutputImage::ImageDimension;
    static constexpr unsigned int KernelDimension = TKernel::NeighborhoodDimension;
  
    /** Type of the pixels in the Kernel. */
    using KernelPixelType = typename TKernel::PixelType;
  
  #ifdef ITK_USE_CONCEPT_CHECKING
    // Begin concept checking
    itkConceptMacro(InputConvertibleToOutputCheck, (Concept::Convertible<PixelType, typename TOutputImage::PixelType>));
    itkConceptMacro(SameDimensionCheck1, (Concept::SameDimension<InputImageDimension, OutputImageDimension>));
    itkConceptMacro(SameDimensionCheck2, (Concept::SameDimension<InputImageDimension, KernelDimension>));
    itkConceptMacro(InputLessThanComparableCheck, (Concept::LessThanComparable<PixelType>));
    itkConceptMacro(KernelGreaterThanComparableCheck, (Concept::GreaterThanComparable<KernelPixelType>));
    // End concept checking
  #endif
  
  protected:
    BasicErodeImageFilter();
    ~BasicErodeImageFilter() override = default;
  
    /** Evaluate image neighborhood with kernel to find the new value
     * for the center pixel value.
     *
     * It will return the minimum value of the image pixels whose corresponding
     * element in the structuring element is positive. This version of
     * Evaluate is used for non-boundary pixels. */
    PixelType
    Evaluate(const NeighborhoodIteratorType & nit,
             const KernelIteratorType         kernelBegin,
             const KernelIteratorType         kernelEnd) override;
  
  private:
    // Default boundary condition for erosion filter, defaults to
    // NumericTraits<PixelType>::max()
    DefaultBoundaryConditionType m_ErodeBoundaryCondition;
  }; // end of class
  } // end namespace itk
  
  #ifndef ITK_MANUAL_INSTANTIATION
  #  include "itkBasicErodeImageFilter.hxx"
  #endif
  
  #endif
  