text: /*=========================================================================
   *
   *  Copyright Insight Software 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
   *
   *         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:
    /** Standard class typedefs. */
    typedef BasicErodeImageFilter                                       Self;
    typedef MorphologyImageFilter< TInputImage, TOutputImage, TKernel > Superclass;
    typedef SmartPointer< Self >                                        Pointer;
    typedef SmartPointer< const Self >                                  ConstPointer;
  
    /** Standard New method. */
    itkNewMacro(Self);
  
    /** Runtime information support. */
    itkTypeMacro(BasicErodeImageFilter,
                 MorphologyImageFilter);
  
    /** Declaration of pixel type. */
    typedef typename Superclass::PixelType PixelType;
  
    /** Kernel (structuring element) iterator. */
    typedef typename Superclass::KernelIteratorType KernelIteratorType;
  
    /** Neighborhood iterator type. */
    typedef typename Superclass::NeighborhoodIteratorType NeighborhoodIteratorType;
  
    /** Kernel typedef. */
    typedef typename Superclass::KernelType KernelType;
  
    /** Default boundary condition type */
    typedef typename Superclass::DefaultBoundaryConditionType DefaultBoundaryConditionType;
  
    /** ImageDimension constants */
    itkStaticConstMacro(InputImageDimension, unsigned int,
                        TInputImage::ImageDimension);
    itkStaticConstMacro(OutputImageDimension, unsigned int,
                        TOutputImage::ImageDimension);
    itkStaticConstMacro(KernelDimension, unsigned int,
                        TKernel::NeighborhoodDimension);
  
    /** Type of the pixels in the Kernel. */
    typedef typename TKernel::PixelType KernelPixelType;
  
  #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() {}
  
    /** 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. */
    virtual PixelType Evaluate(const NeighborhoodIteratorType & nit,
                               const KernelIteratorType kernelBegin,
                               const KernelIteratorType kernelEnd) ITK_OVERRIDE;
  
  private:
    ITK_DISALLOW_COPY_AND_ASSIGN(BasicErodeImageFilter);
  
    // 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
  