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StridedImageIterator [Image Iterators] |
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Iterator to be used when pixels are to be skipped. More...
#include <vigra/imageiterator.hxx>
Public Types | |
typedef Base::difference_type | difference_type |
typedef Base::pointer | pointer |
Public Member Functions | |
StridedImageIterator () | |
StridedImageIterator (pointer base, int ystride, int xskip, int yskip) |
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
typedef Base::difference_type difference_type |
the iterator's difference type (argument type of iter[diff]
)
Reimplemented from ImageIteratorBase.
typedef Base::pointer pointer |
the iterator's pointer type (return type of iter.operator->()
)
Reimplemented from ImageIteratorBase.
StridedImageIterator | ( | pointer | base, | |
int | ystride, | |||
int | xskip, | |||
int | 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.
Default constructor
© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de) |
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