itkLineConstIterator.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 __itkLineConstIterator_h
#define __itkLineConstIterator_h

#include "itkIndex.h"
#include "itkImage.h"

namespace itk
{
template< class TImage >
class ITK_EXPORT LineConstIterator
{
public:

  typedef LineConstIterator Self;

  itkStaticConstMacro(ImageIteratorDimension, unsigned int,
                      TImage::ImageDimension);

  typedef typename TImage::IndexType      IndexType;

  typedef typename TImage::OffsetType      OffsetType;

  typedef typename TImage::SizeType      SizeType;

  typedef typename TImage::RegionType RegionType;

  typedef typename TImage::SpacingType SpacingType;

  typedef typename TImage::PointType PointType;

  typedef TImage ImageType;

  typedef typename TImage::PixelContainer  PixelContainer;
  typedef typename PixelContainer::Pointer PixelContainerPointer;

  typedef typename TImage::InternalPixelType InternalPixelType;

  typedef typename TImage::PixelType PixelType;

  typedef typename TImage::AccessorType AccessorType;

  itkTypeMacro(LineConstIterator, None);

  static unsigned int GetImageIteratorDimension()
  {
    return TImage::ImageDimension;
  }

  const IndexType GetIndex()
  {
    return m_CurrentImageIndex;
  }

  const PixelType Get(void) const
  {
    return m_Image->GetPixel(m_CurrentImageIndex);
  }

  bool IsAtEnd()
  {
    return m_IsAtEnd;
  }

  void GoToBegin();

  void operator++();

  Self & operator=(const Self & it);

  LineConstIterator(const ImageType *imagePtr, const IndexType & firstIndex, const IndexType & lastIndex);

  virtual ~LineConstIterator() {}

protected: //made protected so other iterators can access
  typename ImageType::ConstWeakPointer m_Image;

  RegionType m_Region;

  bool m_IsAtEnd;

  IndexType m_CurrentImageIndex;
  IndexType m_StartIndex;
  IndexType m_LastIndex;
  IndexType m_EndIndex;  // one past the end of the line in the m_MainDirection

  // The dimension with the largest difference between start and end
  unsigned int m_MainDirection;

  // Accumulated error for the other dimensions
  IndexType m_AccumulateError;

  // Increment for the error for each step. Two times the difference between
  // start and end
  IndexType m_IncrementError;

  // If enough is accumulated for a dimension, the index has to be
  // incremented. Will be the number of pixels in the line
  IndexType m_MaximalError;

  // Direction of increment. -1 or 1
  IndexType m_OverflowIncrement;

  // After an overflow, the accumulated error is reduced again. Will be
  // two times the number of pixels in the line
  IndexType m_ReduceErrorAfterIncrement;
};
} // end namespace itk

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

#endif