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StridedImageIterator< PIXELTYPE > Class Template Reference | ![]() |
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 (pointer base, int ystride, int xskip, int yskip) | |
StridedImageIterator () |
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
typedef Base::pointer pointer |
the iterator's pointer type (return type of iter.operator->()
)
Reimplemented from ImageIteratorBase< StridedImageIterator< PIXELTYPE >, PIXELTYPE, PIXELTYPE &, PIXELTYPE *, StridedArrayTag >.
typedef Base::difference_type difference_type |
the iterator's difference type (argument type of iter[diff]
)
Reimplemented from ImageIteratorBase< StridedImageIterator< PIXELTYPE >, PIXELTYPE, PIXELTYPE &, PIXELTYPE *, StridedArrayTag >.
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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