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/*========================================================================= |
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Program: Insight Segmentation & Registration Toolkit |
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Module: $RCSfile: itkImageRegionReverseConstIterator.h.html,v $ |
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Language: C++ |
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Date: $Date: 2006/01/17 19:15:39 $ |
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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 __itkImageRegionReverseConstIterator_h |
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#define __itkImageRegionReverseConstIterator_h |
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#include "itkImageReverseConstIterator.h" |
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namespace itk |
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{ |
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/** |
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* \class ImageRegionReverseConstIterator |
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* \brief A multi-dimensional image iterator designed to walk a specified image |
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* region in reverse. |
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* |
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* ImageRegionReverseConstIterator is a templated class to represent a |
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* multi-dimensional iterator. ImageRegionReverseConstIterator is templated |
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* over the dimension of the image and the data type of the |
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* image. ImageRegionReverseConstIterator is constrained to walk only |
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* within the specified region. |
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* |
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* ImageRegionReverseConstIterator is a multi-dimensional iterator, |
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* requiring more information be specified before the iterator can be |
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* used than conventional iterators. Whereas the std::vector::iterator |
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* from the STL only needs to be passed a pointer to establish the |
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* iterator, the multi-dimensional image iterator needs a pointer, the |
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* size of the buffer, the size of the region, the start index of the |
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* buffer, and the start index of the region. To gain access to this |
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* information, ImageRegionReverseConstIterator holds a reference to the |
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* image over which it is traversing. |
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* |
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* ImageRegionReverseConstIterator assumes a particular layout of the image |
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* data. The is arranged in a 1D array as if it were |
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* [][][][slice][row][col] with Index[0] = col, Index[1] = row, |
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* Index[2] = slice, etc. |
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* |
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* operator++ provides a simple syntax for walking around a region of |
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* a multidimensional image. For a reverse iterator, operator++ moves |
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* backwards through the region. operator++ iterates across a row, |
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* constraining the movement to within a region of image. When the |
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* iterator reaches the boundary of the region along a row, the |
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* iterator automatically wraps to the previous row, starting at the last |
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* pixel in the row that is part of the region. This allows for simple |
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* processing loops of the form: |
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* |
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* \code |
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* |
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* it = it.Begin(); |
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* for (; !it.IsAtEnd(); ++it) |
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* { |
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** *it += 100.0; |
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** } |
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* |
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* \endcode |
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* |
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* \par MORE INFORMATION |
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* For a complete description of the ITK Image Iterators and their API, please |
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* see the Iterators chapter in the ITK Software Guide. The ITK Software Guide |
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* is available in print and as a free .pdf download from http://www.itk.org. |
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* |
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* \ingroup ImageIterators |
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* |
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* \sa ImageConstIterator \sa ConditionalConstIterator |
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* \sa ConstNeighborhoodIterator \sa ConstShapedNeighborhoodIterator |
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* \sa ConstSliceIterator \sa CorrespondenceDataStructureIterator |
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* \sa FloodFilledFunctionConditionalConstIterator |
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* \sa FloodFilledImageFunctionConditionalConstIterator |
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* \sa FloodFilledImageFunctionConditionalIterator |
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* \sa FloodFilledSpatialFunctionConditionalConstIterator |
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* \sa FloodFilledSpatialFunctionConditionalIterator |
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* \sa ImageConstIterator \sa ImageConstIteratorWithIndex |
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* \sa ImageIterator \sa ImageIteratorWithIndex |
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* \sa ImageLinearConstIteratorWithIndex \sa ImageLinearIteratorWithIndex |
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* \sa ImageRandomConstIteratorWithIndex \sa ImageRandomIteratorWithIndex |
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* \sa ImageRegionConstIterator \sa ImageRegionConstIteratorWithIndex |
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* \sa ImageRegionExclusionConstIteratorWithIndex |
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* \sa ImageRegionExclusionIteratorWithIndex |
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* \sa ImageRegionIterator \sa ImageRegionIteratorWithIndex |
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* \sa ImageRegionReverseConstIterator \sa ImageRegionReverseIterator |
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* \sa ImageReverseConstIterator \sa ImageReverseIterator |
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* \sa ImageSliceConstIteratorWithIndex \sa ImageSliceIteratorWithIndex |
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* \sa NeighborhoodIterator \sa PathConstIterator \sa PathIterator |
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* \sa ShapedNeighborhoodIterator \sa SliceIterator |
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* \sa ImageConstIteratorWithIndex */ |
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template<typename TImage> |
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class ITK_EXPORT ImageRegionReverseConstIterator : public ImageReverseConstIterator<TImage> |
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{ |
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public: |
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/** Standard class typedefs. */ |
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typedef ImageRegionReverseConstIterator Self; |
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TDA |
typedef ImageReverseConstIterator<TImage> Superclass; |
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/** Dimension of the image the iterator walks. This enum is needed so that |
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* 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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enum { ImageIteratorDimension = Superclass::ImageIteratorDimension }; |
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/** Index typedef support. 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 Superclass::IndexType IndexType; |
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TDA |
typedef typename Superclass::IndexValueType IndexValueType; |
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/** Size typedef support. 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 Superclass::SizeType SizeType; |
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TDA |
typedef typename Superclass::SizeValueType SizeValueType; |
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/** Offset typedef support. 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 Superclass::OffsetType OffsetType; |
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TDA |
typedef typename Superclass::OffsetValueType OffsetValueType; |
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/** Region typedef support. */ |
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typedef typename Superclass::RegionType RegionType; |
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/** Image typedef support. 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 Superclass::ImageType 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 Superclass::PixelContainer PixelContainer; |
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typedef typename PixelContainer::Pointer PixelContainerPointer; |
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/** Internal Pixel Type */ |
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typedef typename Superclass::InternalPixelType InternalPixelType; |
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/** External Pixel Type */ |
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typedef typename Superclass::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 Superclass::AccessorType AccessorType; |
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/** Run-time type information (and related methods). */ |
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itkTypeMacro(ImageRegionReverseConstIterator, ImageReverseConstIterator); |
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/** Default constructor. Needed since we provide a cast constructor. */ |
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ImageRegionReverseConstIterator() : Superclass() |
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**{ |
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m_SpanBeginOffset = 0; |
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m_SpanEndOffset = 0; |
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**} |
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/** Constructor establishes an iterator to walk a particular image and a |
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* particular region of that image. */ |
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ImageRegionReverseConstIterator(ImageType *ptr, |
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const RegionType ®ion) |
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****: Superclass(ptr, region) |
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**{ |
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m_SpanBeginOffset = this->m_BeginOffset; |
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m_SpanEndOffset = this->m_BeginOffset - static_cast<long>(this->m_Region.GetSize()[0]); |
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**} |
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|
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/** Constructor that can be used to cast from an ImageIterator to an |
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* ImageRegionReverseConstIterator. Many routines return an ImageIterator |
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* but for a particular task, you may want an |
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* ImageRegionReverseConstIterator. Rather than provide overloaded APIs |
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* that return different types of Iterators, itk returns |
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* ImageIterators and uses constructors to cast from an |
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* ImageIterator to a ImageRegionReverseConstIterator. */ |
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ImageRegionReverseConstIterator( const ImageConstIterator<TImage> &it):Superclass(it) |
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**{ |
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IndexType ind = this->GetIndex(); |
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m_SpanBeginOffset = this->m_Offset + static_cast<long>(this->m_Region.GetSize()[0]) |
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******- (ind[0] - this->m_Region.GetIndex()[0]); |
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m_SpanEndOffset = m_SpanBeginOffset - static_cast<long>(this->m_Region.GetSize()[0]); |
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**} |
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|
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/** Constructor that takes in a reverse image iterator. This can be used |
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* to cast between the various types of reverse image iterators. */ |
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ImageRegionReverseConstIterator( const ImageReverseConstIterator<TImage> &it):Superclass(it) |
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**{ |
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IndexType ind = this->GetIndex(); |
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m_SpanBeginOffset = this->m_Offset + static_cast<long>(this->m_Region.GetSize()[0]) |
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******- (ind[0] - this->m_Region.GetIndex()[0]); |
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m_SpanEndOffset = m_SpanBeginOffset - static_cast<long>(this->m_Region.GetSize()[0]); |
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**} |
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|
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***/** Constructor that takes in an image region iterator. This can be used |
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* to cast between the various types of reverse image iterators. */ |
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ImageRegionReverseConstIterator( const ImageRegionIterator<TImage> &it):Superclass(it) |
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**{ |
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IndexType ind = this->GetIndex(); |
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m_SpanBeginOffset = this->m_Offset + static_cast<long>(this->m_Region.GetSize()[0]) |
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******- (ind[0] - this->m_Region.GetIndex()[0]); |
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m_SpanEndOffset = m_SpanBeginOffset - static_cast<long>(this->m_Region.GetSize()[0]); |
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**} |
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*/** Move an iterator to the beginning of the region. "Begin" for a reverse |
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*** iterator is the last pixel in the region. */ |
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void GoToBegin() |
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**{ |
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Superclass::GoToBegin(); |
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// reset the span offsets |
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m_SpanBeginOffset = this->m_BeginOffset; |
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m_SpanEndOffset = this->m_BeginOffset |
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******- static_cast<long>(this->m_Region.GetSize()[0]); |
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**}; |
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|
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*/** Move an iterator to the end of the region. "End" for a reverse iterator |
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*** is defined as one pixel before the first pixel in the region. */ |
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void GoToEnd() |
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**{ |
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Superclass::GoToEnd(); |
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// reset the span offsets |
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m_SpanEndOffset = this->m_EndOffset; |
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m_SpanBeginOffset = m_SpanEndOffset |
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******+ static_cast<long>(this->m_Region.GetSize()[0]); |
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**}; |
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|
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/** Return an iterator for the beginning of the region. "Begin" for a reverse |
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* iterator is the last pixel in the region. |
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* \deprecated Use GoToBegin() instead */ |
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Self Begin(void) const; |
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/** Return an iterator for the end of the region. "End" for a |
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*** reverse iterator is one pixel before the first pixel in the |
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*** region. |
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*** \deprecated Use GoToEnd() instead */ |
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Self End(void) const; |
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/** Set the index. No bounds checking is performed. This is overridden |
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* from the parent because we have an extra ivar. |
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* \sa GetIndex */ |
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void SetIndex(const IndexType &ind) |
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**{ Superclass::SetIndex(ind); |
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LEN |
m_SpanBeginOffset = this->m_Offset + static_cast<long>(this->m_Region.GetSize()[0]) |
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******- (ind[0] - this->m_Region.GetIndex()[0]); |
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m_SpanEndOffset = m_SpanBeginOffset - static_cast<long>(this->m_Region.GetSize()[0]); |
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**} |
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|
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/** iterator's index. For a reverse iterator, this moves backwards |
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* through the region. This operator will constrain the iterator |
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* within the region (i.e. the iterator will automatically wrap from |
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* the start of the row of the region to the end of the previous row |
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* of the region) up until the iterator tries to moves before the |
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* first pixel of the region. Here, the iterator will be set to be |
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* one pixel before the start of the region. |
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* \sa operator++(int). */ |
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Self & |
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operator++() |
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**{ |
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if (--this->m_Offset <= m_SpanEndOffset) |
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{ |
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// We have past the beginning of the span (row), need to wrap around. |
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// First move forward one pixel, because we are going to use a different |
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// algorithm to compute the next pixel |
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this->m_Offset++; |
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// Get the index of the first pixel on the span (row) |
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typename ImageConstIterator<TImage>::IndexType |
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LEN,IND |
********ind = this->m_Image->ComputeIndex( static_cast<OffsetValueType>(this->m_Offset) ); |
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const typename ImageConstIterator<TImage>::IndexType& |
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********startIndex = this->m_Region.GetIndex(); |
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const typename ImageConstIterator<TImage>::SizeType& |
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********size = this->m_Region.GetSize(); |
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|
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// Deccrement along a row, then wrap at the beginning of the region row. |
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bool done; |
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unsigned int dim; |
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// Check to see if we are past the first pixel in the region |
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// Note that --ind[0] moves to the previous pixel along the row. |
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done = (--ind[0] == startIndex[0] - 1); |
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for (unsigned int i=1; done && i < ImageIteratorDimension; i++) |
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{ |
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done = (ind[i] == startIndex[i]); |
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} |
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// if the iterator is outside the region (but not past region begin) then |
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// we need to wrap around the region |
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dim = 0; |
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if (!done) |
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{ |
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while ( (dim < ImageIteratorDimension - 1) |
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&& (ind[dim] < startIndex[dim]) ) |
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{ |
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ind[dim] = startIndex[dim] + static_cast<long>(size[dim]) - 1; |
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ind[++dim]--; |
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} |
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} |
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this->m_Offset = this->m_Image->ComputeOffset( ind ); |
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m_SpanBeginOffset = this->m_Offset; |
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m_SpanEndOffset = m_SpanBeginOffset - static_cast<long>(size[0]); |
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} |
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return *this; |
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**} |
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|
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/** Decrement (prefix) the fastest moving dimension of the iterator's index. |
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* For a reverse iterator, this moves forward through the region. |
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* This operator will constrain the iterator within the region (i.e. the |
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* iterator will automatically wrap from the end of the row of the region |
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* to the start of the next row of the region) up until the iterator |
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* tries to moves past the last pixel of the region. Here, the iterator |
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* will be set to be one pixel past the end of the region. |
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* \sa operator--(int) */ |
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Self & operator--() |
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**{ |
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if (++this->m_Offset >= m_SpanBeginOffset) |
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{ |
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// We have reached the end of the span (row), need to wrap around. |
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|
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// First back up one pixel, because we are going to use a different |
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// algorithm to compute the next pixel |
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--this->m_Offset; |
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|
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// Get the index of the last pixel on the span (row) |
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typename ImageConstIterator<TImage>::IndexType |
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LEN,IND |
********ind = this->m_Image->ComputeIndex( static_cast<OffsetValueType>(this->m_Offset) ); |
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|
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const typename ImageIterator<TImage>::IndexType& |
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********startIndex = this->m_Region.GetIndex(); |
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const typename ImageIterator<TImage>::SizeType& |
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********size = this->m_Region.GetSize(); |
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|
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// Increment along a row, then wrap at the end of the region row. |
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bool done; |
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unsigned int dim; |
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|
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// Check to see if we are past the last pixel in the region |
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// Note that ++ind[0] moves to the next pixel along the row. |
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done = (++ind[0] == startIndex[0] + static_cast<long>(size[0])); |
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for (unsigned int i=1; done && i < ImageIteratorDimension; i++) |
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{ |
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done = (ind[i] == startIndex[i] + static_cast<long>(size[i]) - 1); |
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} |
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|
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// if the iterator is outside the region (but not past region end) then |
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// we need to wrap around the region |
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dim = 0; |
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if (!done) |
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{ |
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while ( (dim < ImageIteratorDimension - 1) |
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LEN |
&& (ind[dim] > startIndex[dim] + static_cast<long>(size[dim]) - 1) ) |
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{ |
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ind[dim] = startIndex[dim]; |
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ind[++dim]++; |
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} |
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} |
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this->m_Offset = this->m_Image->ComputeOffset( ind ); |
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m_SpanBeginOffset = this->m_Offset; |
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m_SpanEndOffset = this->m_Offset - static_cast<long>(size[0]); |
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} |
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return *this; |
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**} |
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|
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protected: |
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unsigned long m_SpanBeginOffset; // offset to last pixel in the row |
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unsigned long m_SpanEndOffset; // offset to one pixel before the row |
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|
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}; |
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|
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} // end namespace itk |
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|
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#ifndef ITK_MANUAL_INSTANTIATION |
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#include "itkImageRegionReverseConstIterator.txx" |
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#endif |
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|
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#endif |
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|
