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Public Types | Protected Member Functions
ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided > Class Template Reference

Base class for 2D random access iterators. More...

#include <vigra/imageiterator.hxx>

List of all members.

Public Types

typedef ColumnIteratorSelector::res column_iterator
typedef Diff2D difference_type
typedef REFERENCE index_reference
typedef image_traverser_tag iterator_category
typedef
detail::DirectionSelector
< StridedOrUnstrided >
::template type< pointer
MoveX
typedef
detail::DirectionSelector
< StridedArrayTag >::template
type< int > 
MoveY
typedef PIXELTYPE PixelType
typedef POINTER pointer
typedef REFERENCE reference
typedef RowIteratorSelector::res row_iterator
typedef PIXELTYPE value_type

Public Member Functions

Comparison of Iterators
bool operator== (ImageIteratorBase const &rhs) const
bool operator!= (ImageIteratorBase const &rhs) const
difference_type operator- (ImageIteratorBase const &rhs) const
Random navigation
IMAGEITERATOR & operator+= (difference_type const &s)
IMAGEITERATOR & operator-= (difference_type const &s)
IMAGEITERATOR operator+ (difference_type const &s) const
IMAGEITERATOR operator- (difference_type const &s) const
Access the Pixels
reference operator* () const
pointer operator-> () const
index_reference operator[] (Diff2D const &d) const
index_reference operator() (int dx, int dy) const
pointer operator[] (int dy) const

Public Attributes

Specify coordinate to operate on
MoveX x
MoveY y

Protected Member Functions

 ImageIteratorBase (pointer base, int ystride)
 ImageIteratorBase (pointer base, int xstride, int ystride)
 ImageIteratorBase ()
 ImageIteratorBase (ImageIteratorBase const &rhs)
ImageIteratorBaseoperator= (ImageIteratorBase const &rhs)

Detailed Description

template<class IMAGEITERATOR, class PIXELTYPE, class REFERENCE, class POINTER, class StridedOrUnstrided = UnstridedArrayTag>
class vigra::ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided >

Base class for 2D random access iterators.

This class contains the navigational part of the iterator. It is usually not constructed directly, but via some derived class such as ImageIterator or StridedImageIterator.

#include <vigra/imageiterator.hxx>

Namespace: vigra

The usage examples assume that you constructed two iterators like this:

    vigra::ImageIterator<SomePixelType> iterator(base, width);
    vigra::ImageIterator<SomePixelType> iterator1(base, width);

See the paper: U. Koethe: Reusable Algorithms in Image Processing for a discussion of the concepts behind ImageIterators.


Member Typedef Documentation

typedef PIXELTYPE value_type

The underlying image's pixel type.

typedef PIXELTYPE PixelType

deprecated, use value_type instead.

typedef REFERENCE reference

the iterator's reference type (return type of *iter)

typedef REFERENCE index_reference

the iterator's index reference type (return type of iter[diff])

typedef POINTER pointer

the iterator's pointer type (return type of iter.operator->())

Reimplemented in ImageIterator< PIXELTYPE >, ConstImageIterator< PIXELTYPE >, StridedImageIterator< PIXELTYPE >, and ConstStridedImageIterator< PIXELTYPE >.

the iterator's difference type (argument type of iter[diff])

Reimplemented in ImageIterator< PIXELTYPE >, ConstImageIterator< PIXELTYPE >, StridedImageIterator< PIXELTYPE >, and ConstStridedImageIterator< PIXELTYPE >.

typedef image_traverser_tag iterator_category

the iterator tag (image traverser)

typedef RowIteratorSelector::res row_iterator

The associated row iterator.

typedef ColumnIteratorSelector::res column_iterator

The associated column iterator.

typedef detail::DirectionSelector<StridedOrUnstrided>::template type<pointer> MoveX

Let operations act in X direction

typedef detail::DirectionSelector<StridedArrayTag>::template type<int> MoveY

Let operations act in Y direction


Constructor & Destructor Documentation

ImageIteratorBase ( pointer  base,
int  ystride 
) [protected]

Construct from raw memory with a vertical stride of ystride. ystride must equal the physical image width (row length), even if the iterator will only be used for a sub image. This constructor must only be called for unstrided iterators (StridedOrUnstrided == UnstridedArrayTag)

ImageIteratorBase ( pointer  base,
int  xstride,
int  ystride 
) [protected]

Construct from raw memory with a horizontal stride of xstride and a vertical stride of ystride. This constructor may be used for iterators that shall skip pixels. Thus, it must only be called for strided iterators (StridedOrUnstrided == StridedArrayTag)

ImageIteratorBase ( ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided > const &  rhs) [protected]

Copy constructor

ImageIteratorBase ( ) [protected]

Default constructor


Member Function Documentation

bool operator== ( ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided > const &  rhs) const

usage: iterator == iterator1

bool operator!= ( ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided > const &  rhs) const

usage: iterator != iterator1

difference_type operator- ( ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided > const &  rhs) const

usage: Diff2D dist = iterator - iterator1

ImageIteratorBase& operator= ( ImageIteratorBase< IMAGEITERATOR, PIXELTYPE, REFERENCE, POINTER, StridedOrUnstrided > const &  rhs) [protected]

Copy assignment

IMAGEITERATOR& operator+= ( difference_type const &  s)

Add offset via Diff2D

IMAGEITERATOR& operator-= ( difference_type const &  s)

Subtract offset via Diff2D

IMAGEITERATOR operator+ ( difference_type const &  s) const

Add a distance

IMAGEITERATOR operator- ( difference_type const &  s) const

Subtract a distance

reference operator* ( ) const

Access current pixel.
usage: SomePixelType value = *iterator

pointer operator-> ( ) const

Call member of current pixel.
usage: iterator->pixelMemberFunction()

index_reference operator[] ( Diff2D const &  d) const

Access pixel at offset from current location.
usage: SomePixelType value = iterator[Diff2D(1,1)]

index_reference operator() ( int  dx,
int  dy 
) const

Access pixel at offset (dx, dy) from current location.
usage: SomePixelType value = iterator(dx, dy)

pointer operator[] ( int  dy) const

Read pixel with offset [dy][dx] from current pixel. Note that the 'x' index is the trailing index.
usage: SomePixelType value = iterator[dy][dx]


Member Data Documentation

Refer to iterator's x coordinate. Usage examples:

            ++iterator.x;        // move one step to the right
            --iterator.x;        // move one step to the left
            iterator.x += dx;    // move dx steps to the right
            iterator.x -= dx;    // move dx steps to the left
            bool notAtEndOfRow = iterator.x < lowerRight.x;   // compare x coordinates of two iterators
            int width = lowerRight.x - upperLeft.x;           // calculate difference of x coordinates
                                                              // between two iterators

Refer to iterator's y coordinate. Usage examples:

            ++iterator.y;        // move one step down
            --iterator.y;        // move one step up
            iterator.y += dy;    // move dy steps down
            iterator.y -= dy;    // move dy steps up
            bool notAtEndOfColumn = iterator.y < lowerRight.y; // compare y coordinates of two iterators
            int height = lowerRight.y - upperLeft.y;           // calculate difference of y coordinates
                                                               // between two iterators

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

© Ullrich Köthe (ullrich.koethe@iwr.uni-heidelberg.de)
Heidelberg Collaboratory for Image Processing, University of Heidelberg, Germany

html generated using doxygen and Python
vigra 1.7.0 (Thu Aug 25 2011)