itkImageRegionConstIterator.h

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/*=========================================================================
 *
 *  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 itkImageRegionConstIterator_h
#define itkImageRegionConstIterator_h

#include "itkImageIterator.h"

namespace itk
{
template< typename TImage >
class ITK_TEMPLATE_EXPORT ImageRegionConstIterator:public ImageConstIterator< TImage >
{
public:
  using Self = ImageRegionConstIterator;
  using Superclass = ImageConstIterator< TImage >;

  static constexpr unsigned int ImageIteratorDimension = Superclass::ImageIteratorDimension;

  using IndexType = typename Superclass::IndexType;
  using SizeType = typename Superclass::SizeType;
  using OffsetType = typename Superclass::OffsetType;
  using RegionType = typename Superclass::RegionType;
  using ImageType = typename Superclass::ImageType;
  using PixelContainer = typename Superclass::PixelContainer;
  using PixelContainerPointer = typename Superclass::PixelContainerPointer;
  using InternalPixelType = typename Superclass::InternalPixelType;
  using PixelType = typename Superclass::PixelType;
  using AccessorType = typename Superclass::AccessorType;

  itkTypeMacro(ImageRegionConstIterator, ImageConstIterator);

  ImageRegionConstIterator():ImageConstIterator< TImage >()
  {
    m_SpanBeginOffset = 0;
    m_SpanEndOffset = 0;
  }

  ImageRegionConstIterator(const ImageType *ptr,
                           const RegionType & region):
    ImageConstIterator< TImage >(ptr, region)
  {
    m_SpanBeginOffset = this->m_BeginOffset;
    m_SpanEndOffset   = this->m_BeginOffset + static_cast< OffsetValueType >( this->m_Region.GetSize()[0] );
  }

  ImageRegionConstIterator(const ImageIterator< TImage > & it)
  {
    this->ImageConstIterator< TImage >::operator=(it);

    IndexType ind = this->GetIndex();
    m_SpanEndOffset = this->m_Offset + static_cast< OffsetValueType >( this->m_Region.GetSize()[0] )
                      - ( ind[0] - this->m_Region.GetIndex()[0] );
    m_SpanBeginOffset = m_SpanEndOffset
                        - static_cast< OffsetValueType >( this->m_Region.GetSize()[0] );
  }

  ImageRegionConstIterator(const ImageConstIterator< TImage > & it)
  {
    this->ImageConstIterator< TImage >::operator=(it);

    IndexType ind = this->GetIndex();
    m_SpanEndOffset = this->m_Offset + static_cast< OffsetValueType >( this->m_Region.GetSize()[0] )
                      - ( ind[0] - this->m_Region.GetIndex()[0] );
    m_SpanBeginOffset = m_SpanEndOffset
                        - static_cast< OffsetValueType >( this->m_Region.GetSize()[0] );
  }

  void GoToBegin()
  {
    Superclass::GoToBegin();

    // reset the span offsets
    m_SpanBeginOffset = this->m_BeginOffset;
    m_SpanEndOffset   = this->m_BeginOffset + static_cast< OffsetValueType >( this->m_Region.GetSize()[0] );
  }

  void GoToEnd()
  {
    Superclass::GoToEnd();

    // reset the span offsets
    m_SpanEndOffset = this->m_EndOffset;
    m_SpanBeginOffset = m_SpanEndOffset - static_cast< OffsetValueType >( this->m_Region.GetSize()[0] );
  }

  void SetIndex(const IndexType & ind) override
  {
    Superclass::SetIndex(ind);
    m_SpanEndOffset = this->m_Offset + static_cast< OffsetValueType >( this->m_Region.GetSize()[0] )
                      - ( ind[0] - this->m_Region.GetIndex()[0] );
    m_SpanBeginOffset = m_SpanEndOffset - static_cast< OffsetValueType >( this->m_Region.GetSize()[0] );
  }

  Self &
  operator++()
  {
    if ( ++this->m_Offset >= m_SpanEndOffset )
      {
      this->Increment();
      }
    return *this;
  }

  Self & operator--()
  {
    if ( --this->m_Offset < m_SpanBeginOffset )
      {
      this->Decrement();
      }
    return *this;
  }

protected:
  OffsetValueType m_SpanBeginOffset; // one pixel before the beginning of the span
                                   // (row)
  OffsetValueType m_SpanEndOffset;   // one pixel past the end of the span (row)

private:
  void Increment(); // advance in a direction other than the fastest moving

  void Decrement(); // go back in a direction other than the fastest moving
};
} // end namespace itk

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

#endif