itkImageScanlineConstIterator.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 __itkImageScanlineConstIterator_h
#define __itkImageScanlineConstIterator_h

#include "itkImageIterator.h"

namespace itk
{
template< typename TImage >
class ImageScanlineConstIterator:
    public ImageConstIterator< TImage >
{
public:
  typedef ImageScanlineConstIterator   Self;
  typedef ImageConstIterator< TImage > Superclass;

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

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

  itkTypeMacro(ImageScanlineConstIterator, ImageConstIterator);

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

  ImageScanlineConstIterator(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] );
  }

  ImageScanlineConstIterator(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] );
  }

  ImageScanlineConstIterator(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 GoToBeginOfLine(void)
  {
    this->m_Offset = m_SpanBeginOffset;
  }

  void GoToEndOfLine(void)
  {
    this->m_Offset = m_SpanEndOffset;
  }

  inline bool IsAtEndOfLine(void)
  {
    return this->m_Offset >= m_SpanEndOffset;
  }


  void SetIndex(const IndexType & ind)
  {
    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] );
  }

  inline void NextLine(void)
  {
    this->Increment();
  };

  Self& operator++()
  {
    itkAssertInDebugAndIgnoreInReleaseMacro( !this->IsAtEndOfLine() );
    ++this->m_Offset;
    return *this;
  }

  Self& operator--()
  {
    itkAssertInDebugAndIgnoreInReleaseMacro( !this->IsAtEndOfLine() );
    --this->m_Offset;
    return *this;
  }


protected:
  OffsetValueType m_SpanBeginOffset; // one pixel the beginning of the scanline
  OffsetValueType m_SpanEndOffset;   // one pixel past the end of the scanline

private:

  /* Move to the beginning of the next scanline
   */
  void Increment();

};
} // end namespace itk

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

#endif