pixel_2d_locator_base Class Template Reference [Models, Models] #include <locator.hpp> List of all members. Detailed Description template<typename Loc, typename XIterator, typename YIterator> class boost::gil::pixel_2d_locator_base< Loc, XIterator, YIterator > base class for models of PixelLocatorConcept Pixel locator is similar to a pixel iterator, but allows for 2D navigation of pixels within an image view. It has a 2D difference_type and supports random access operations like: difference_type offset2(2,3); locator+=offset2; locator[offset2]=my_pixel; In addition, each coordinate acts as a random-access iterator that can be modified separately: "++locator.x()" or "locator.y()+=10" thereby moving the locator horizontally or vertically. It is called a locator because it doesn't implement the complete interface of a random access iterator. For example, increment and decrement operations don't make sense (no way to specify dimension). Also 2D difference between two locators cannot be computed without knowledge of the X position within the image. This base class provides most of the methods and typedefs needed to create a model of a locator. GIL provides two locator models as subclasses of pixel_2d_locator_base. A memory-based locator, memory_based_2d_locator and a virtual locator, virtual_2d_locator. The minimum functionality a subclass must provide is this: class my_locator : public pixel_2d_locator_base<my_locator, ..., ...> { // supply the types for x-iterator and y-iterator typedef ... const_t; // read-only locator template <typename Deref> struct add_deref { typedef ... type; // locator that invokes the Deref dereference object upon pixel access static type make(const my_locator& loc, const Deref& d); }; my_locator(); my_locator(const my_locator& pl); // constructors with dynamic step in y (and x). Only valid for locators with dynamic steps my_locator(const my_locator& loc, coord_t y_step); my_locator(const my_locator& loc, coord_t x_step, coord_t y_step, bool transpose); bool operator==(const my_locator& p) const; // return _references_ to horizontal/vertical iterators. Advancing them moves this locator x_iterator& x(); y_iterator& y(); x_iterator const& x() const; y_iterator const& y() const; // return the vertical distance to another locator. Some models need the horizontal distance to compute it y_coord_t y_distance_to(const my_locator& loc2, x_coord_t xDiff) const; // return true iff incrementing an x-iterator located at the last column will position it at the first // column of the next row. Some models need the image width to determine that. bool is_1d_traversable(x_coord_t width) const; }; Models may choose to override some of the functions in the base class with more efficient versions. Public Types typedef XIterator  x_iterator typedef YIterator  y_iterator typedef std::iterator_traits< x_iterator >::value_type  value_type typedef std::iterator_traits< x_iterator >::reference  reference typedef std::iterator_traits< x_iterator >::difference_type  coord_t typedef point2< coord_t >  difference_type typedef difference_type  point_t typedef point_t::template axis< 0 >::coord_t  x_coord_t typedef point_t::template axis< 1 >::coord_t  y_coord_t typedef difference_type  cached_location_t Public Member Functions bool  operator!= (const Loc &p) const x_iterator  x_at (x_coord_t dx, y_coord_t dy) const x_iterator  x_at (const difference_type &d) const y_iterator  y_at (x_coord_t dx, y_coord_t dy) const y_iterator  y_at (const difference_type &d) const Loc  xy_at (x_coord_t dx, y_coord_t dy) const Loc  xy_at (const difference_type &d) const template<std::size_t D> axis< D >::iterator &  axis_iterator () template<std::size_t D> axis< D >::iterator const &  axis_iterator () const template<std::size_t D> axis< D >::iterator  axis_iterator (const point_t &p) const reference  operator() (x_coord_t dx, y_coord_t dy) const reference  operator[] (const difference_type &d) const reference  operator * () const Loc &  operator+= (const difference_type &d) Loc &  operator-= (const difference_type &d) Loc  operator+ (const difference_type &d) const Loc  operator- (const difference_type &d) const cached_location_t  cache_location (const difference_type &d) const cached_location_t  cache_location (x_coord_t dx, y_coord_t dy) const Static Public Attributes static const std::size_t  num_dimensions = 2 Friends class  pixel_2d_locator The documentation for this class was generated from the following file: locator.hpp

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