StridedImageIterator< PIXELTYPE > Class Template Reference

Iterator to be used when pixels are to be skipped. More...

#include <vigra/imageiterator.hxx>

Inheritance diagram for StridedImageIterator< PIXELTYPE >:

Public Member Functions
	StridedImageIterator ()
	StridedImageIterator (pointer base, std::ptrdiff_t ystride, std::ptrdiff_t xskip, std::ptrdiff_t yskip)
Public Member Functions inherited from ImageIteratorBase< StridedImageIterator< PIXELTYPE >, PIXELTYPE, PIXELTYPE &, PIXELTYPE *, StridedArrayTag >
bool	operator== (ImageIteratorBase const &rhs) const
bool	operator!= (ImageIteratorBase const &rhs) const
difference_type	operator- (ImageIteratorBase const &rhs) const
StridedImageIterator< PIXELTYPE > &	operator+= (difference_type const &s)
StridedImageIterator< PIXELTYPE > &	operator-= (difference_type const &s)
StridedImageIterator< PIXELTYPE >	operator+ (difference_type const &s) const
StridedImageIterator< PIXELTYPE >	operator- (difference_type const &s) const
reference	operator* () const
pointer	operator-> () const
index_reference	operator[] (Diff2D const &d) const
index_reference	operator() (std::ptrdiff_t dx, std::ptrdiff_t dy) const
pointer	operator[] (std::ptrdiff_t dy) const

Additional Inherited Members
Public Types inherited from ImageIteratorBase< StridedImageIterator< PIXELTYPE >, PIXELTYPE, PIXELTYPE &, PIXELTYPE *, StridedArrayTag >
typedef ColumnIteratorSelector::res	column_iterator
typedef Diff2D	difference_type
typedef PIXELTYPE &	index_reference
typedef image_traverser_tag	iterator_category
typedef vigra::detail::DirectionSelector< StridedArrayTag >::template type< pointer >	MoveX
typedef vigra::detail::DirectionSelector< StridedArrayTag >::template type< std::ptrdiff_t >	MoveY
typedef PIXELTYPE	PixelType
typedef PIXELTYPE *	pointer
typedef PIXELTYPE &	reference
typedef RowIteratorSelector::res	row_iterator
typedef PIXELTYPE	value_type
MoveX	x
MoveY	y
	ImageIteratorBase (pointer base, std::ptrdiff_t ystride)
	ImageIteratorBase (pointer base, std::ptrdiff_t xstride, std::ptrdiff_t ystride)
	ImageIteratorBase (ImageIteratorBase const &rhs)
	ImageIteratorBase ()
ImageIteratorBase &	operator= (ImageIteratorBase const &rhs)

Detailed Description

template<class PIXELTYPE>
class vigra::StridedImageIterator< PIXELTYPE >

Iterator to be used when pixels are to be skipped.

This iterator can be used when some pixels shall be automatically skipped, for example if an image is to be sub-sampled: instead of advancing to the next pixel, ++iterator.x jumps to the pixel at a horizontal offset of xskip. Likewise with yskip in vertical direction. Most functions and local types are inherited from ImageIteratorBase.

Usage:

BImage img(w,h);
...
int xskip = 2, yskip = 2;
int wskip = w / xskip + 1, hskip = h / yskip + 1;
 
StridedImageIterator<BImage::value_type> upperLeft(&img(0,0), w, xskip, yskip);
StridedImageIterator<BImage::value_type> lowerRight = upperLeft + Diff2D(wskip, hskip);
 
// now navigation with upperLeft and lowerRight lets the image appear to have half
// the original resolution in either dimension

#include <vigra/imageiterator.hxx>
Namespace: vigra

Constructor & Destructor Documentation

StridedImageIterator() [1/2]

template<class PIXELTYPE>

StridedImageIterator	(	pointer	base,
		std::ptrdiff_t	ystride,
		std::ptrdiff_t	xskip,
		std::ptrdiff_t	yskip )

Construct from raw memory with a vertical stride of ystride, jumping by xskip horizontally and yskip vertically. ystride must be the physical width (row length) of the image.

StridedImageIterator() [2/2]

template<class PIXELTYPE>

StridedImageIterator

(

)

Default constructor

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The documentation for this class was generated from the following file:

• vigra/imageiterator.hxx