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/*========================================================================= |
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Program: Insight Segmentation & Registration Toolkit |
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Module: $RCSfile: itkLineConstIterator.h.html,v $ |
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Language: C++ |
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Date: $Date: 2006/01/17 19:15:41 $ |
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Version: $Revision: 1.4 $ |
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Copyright (c) Insight Software Consortium. All rights reserved. |
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See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details. |
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This software is distributed WITHOUT ANY WARRANTY; without even |
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the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR |
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PURPOSE. See the above copyright notices for more information. |
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=========================================================================*/ |
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#ifndef __itkLineConstIterator_h |
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#define __itkLineConstIterator_h |
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#include "itkIndex.h" |
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#include "itkImage.h" |
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namespace itk |
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{ |
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/** |
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* \class LineConstIterator |
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* \brief Iterator that walks a Bresenham line through an ND image. |
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* |
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* LineConstIterator is an iterator that walks a Bresenham line |
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* through an image. The iterator is constructed similar to other |
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* image iterators except for instead of specifying a region to |
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* traverse, you specify two indices. The interval specified by |
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* the two indices is closed. So, a line iterator specified with |
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* the same start and end index will visit exactly one pixel. |
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* |
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* \code |
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* LineConstIterator<ImageType> it(image, I1, I2); |
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* while (!it.IsAtEnd()) |
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* { |
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** // visits at least 1 pixel |
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** } |
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* \endcode |
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* |
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* This class was contributed by Benjamin King, Experimentelle |
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* Radiologie, Medizinische Hochschule Hannover. |
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* |
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*/ |
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template<class TImage> |
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class ITK_EXPORT LineConstIterator |
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{ |
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public: |
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/** Standard class typedefs. */ |
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typedef LineConstIterator Self; |
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/** Dimension of the image the iterator walks. This constant is needed so |
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* that functions that are templated over image iterator type (as opposed to |
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* being templated over pixel type and dimension) can have compile time |
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* access to the dimension of the image that the iterator walks. */ |
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itkStaticConstMacro(ImageIteratorDimension, unsigned int, |
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TImage::ImageDimension); |
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/** Index typedef support. */ |
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typedef typename TImage::IndexType IndexType; |
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typedef typename TImage::IndexValueType IndexValueType; |
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/** Offset typedef support. */ |
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typedef typename TImage::OffsetType OffsetType; |
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typedef typename TImage::OffsetValueType OffsetValueType; |
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/** Size typedef support. */ |
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typedef typename TImage::SizeType SizeType; |
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typedef typename TImage::SizeValueType SizeValueType; |
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/** Region typedef support */ |
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typedef typename TImage::RegionType RegionType; |
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/** Spacing typedef support */ |
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typedef typename TImage::SpacingType SpacingType; |
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/** Origin typedef support */ |
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typedef typename TImage::PointType PointType; |
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/** Image typedef support. */ |
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typedef TImage ImageType; |
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/** PixelContainer typedef support. Used to refer to the container for |
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* the pixel data. While this was already typdef'ed in the superclass |
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* it needs to be redone here for this subclass to compile properly with gcc. */ |
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typedef typename TImage::PixelContainer PixelContainer; |
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typedef typename PixelContainer::Pointer PixelContainerPointer; |
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/** Internal Pixel Type */ |
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typedef typename TImage::InternalPixelType InternalPixelType; |
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/** External Pixel Type */ |
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typedef typename TImage::PixelType PixelType; |
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/** Accessor type that convert data between internal and external |
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* representations. */ |
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typedef typename TImage::AccessorType AccessorType; |
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/** Run-time type information (and related methods). */ |
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itkTypeMacro(LineConstIterator, None); |
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/** Get the dimension (size) of the index. */ |
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static unsigned int GetImageIteratorDimension() |
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{ |
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return TImage::ImageDimension; |
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} |
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/** Get the index. This provides a read only reference to the index. */ |
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const IndexType GetIndex() |
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{ |
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return m_CurrentImageIndex; |
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} |
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/** Get the pixel value */ |
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const PixelType & Get(void) const |
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{ |
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return m_Image->GetPixel(m_CurrentImageIndex ); |
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} |
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/** Is the iterator at the end of the line? */ |
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bool IsAtEnd() |
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{ |
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return m_IsAtEnd; |
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} |
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/** Move an iterator to the beginning of the line. */ |
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void GoToBegin(); |
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/** Walk forward along the line to the next index in the image. */ |
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void operator++(); |
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/** operator= is provided to make sure the handle to the image is properly |
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* reference counted. */ |
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Self &operator=(const Self& it); |
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/** Constructor establishes an iterator to walk along a line */ |
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LineConstIterator(const ImageType *imagePtr, const IndexType &firstIndex, const IndexType &lastIndex); |
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/** Default Destructor. */ |
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virtual ~LineConstIterator() {}; |
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protected: //made protected so other iterators can access |
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/** Smart pointer to the source image. */ |
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typename ImageType::ConstWeakPointer m_Image; |
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/** Region type to iterate over. */ |
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RegionType m_Region; |
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/** Is the iterator at the end of its walk? */ |
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bool m_IsAtEnd; |
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/** Start, end and current ND index position in the image of the line */ |
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IndexType m_CurrentImageIndex; |
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IndexType m_StartIndex; |
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IndexType m_LastIndex; |
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IndexType m_EndIndex; // one past the end of the line in the m_MainDirection |
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/** Variables that drive the Bresenham-Algorithm */ |
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// The dimension with the largest difference between start and end |
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unsigned int m_MainDirection; |
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// Accumulated error for the other dimensions |
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IndexType m_AccumulateError; |
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// Increment for the error for each step. Two times the difference between |
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// start and end |
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IndexType m_IncrementError; |
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// If enough is accumulated for a dimension, the index has to be |
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// incremented. Will be the number of pixels in the line |
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IndexType m_MaximalError; |
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// Direction of increment. -1 or 1 |
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IndexType m_OverflowIncrement; |
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// After an overflow, the accumulated error is reduced again. Will be |
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// two times the number of pixels in the line |
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IndexType m_ReduceErrorAfterIncrement; |
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}; |
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} // end namespace itk |
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#ifndef ITK_MANUAL_INSTANTIATION |
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#include "itkLineConstIterator.txx" |
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#endif |
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#endif |
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