Chris@16: /*
Chris@16:     Copyright 2005-2007 Adobe Systems Incorporated
Chris@16:    
Chris@16:     Use, modification and distribution are subject to the Boost Software License,
Chris@16:     Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@16:     http://www.boost.org/LICENSE_1_0.txt).
Chris@16: 
Chris@16:     See http://opensource.adobe.com/gil for most recent version including documentation.
Chris@16: */
Chris@16: /*************************************************************************************************/
Chris@16: 
Chris@16: #ifndef GIL_ITERATOR_FROM_2D_H
Chris@16: #define GIL_ITERATOR_FROM_2D_H
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: /// \file               
Chris@16: /// \brief pixel step iterator, pixel image iterator and pixel dereference iterator
Chris@16: /// \author Lubomir Bourdev and Hailin Jin \n
Chris@16: ///         Adobe Systems Incorporated
Chris@16: /// \date   2005-2007 \n Last updated on September 18, 2007
Chris@16: ///
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #include <cassert>
Chris@16: #include <boost/iterator/iterator_facade.hpp>
Chris@16: #include "gil_concept.hpp"
Chris@16: #include "gil_config.hpp"
Chris@16: #include "pixel_iterator.hpp"
Chris@16: #include "locator.hpp"
Chris@16: 
Chris@16: namespace boost { namespace gil {
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: ///                 
Chris@16: ///                 ITERATOR FROM 2D ADAPTOR
Chris@16: ///
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: 
Chris@16: /// \defgroup PixelIteratorModelFromLocator iterator_from_2d
Chris@16: /// \ingroup PixelIteratorModel
Chris@16: /// \brief An iterator over two-dimensional locator. Useful for iterating over the pixels of an image view. Models PixelIteratorConcept, PixelBasedConcept, HasDynamicXStepTypeConcept
Chris@16: 
Chris@16: 
Chris@16: /// \ingroup PixelIteratorModelFromLocator PixelBasedModel
Chris@16: /// \brief Provides 1D random-access navigation to the pixels of the image. Models: PixelIteratorConcept, PixelBasedConcept, HasDynamicXStepTypeConcept
Chris@16: ///
Chris@16: /// Pixels are traversed from the top to the bottom row and from the left to the right 
Chris@16: /// within each row
Chris@16: 
Chris@16: template <typename Loc2>    // Models PixelLocatorConcept
Chris@16: class iterator_from_2d : public iterator_facade<iterator_from_2d<Loc2>,
Chris@16:                                                 typename Loc2::value_type,
Chris@16:                                                 std::random_access_iterator_tag,
Chris@16:                                                 typename Loc2::reference,
Chris@16:                                                 typename Loc2::coord_t> {
Chris@16:     GIL_CLASS_REQUIRE(Loc2, boost::gil, PixelLocatorConcept)
Chris@16: public:
Chris@16:     typedef iterator_facade<iterator_from_2d<Loc2>,
Chris@16:                             typename Loc2::value_type,
Chris@16:                             std::random_access_iterator_tag,
Chris@16:                             typename Loc2::reference,
Chris@16:                             typename Loc2::coord_t> parent_t;
Chris@16:     typedef typename parent_t::reference       reference;
Chris@16:     typedef typename parent_t::difference_type difference_type;
Chris@16:     typedef typename Loc2::x_iterator          x_iterator;
Chris@16:     typedef typename Loc2::point_t             point_t;
Chris@16: 
Chris@16:     std::ptrdiff_t width()         const { return _width; }            // number of pixels per image row
Chris@16:     std::ptrdiff_t x_pos()         const { return _coords.x; }         // current x position
Chris@16:     std::ptrdiff_t y_pos()         const { return _coords.y; }         // current y position
Chris@16: 
Chris@16:     /// For some reason operator[] provided by iterator_adaptor returns a custom class that is convertible to reference
Chris@16:     /// We require our own reference because it is registered in iterator_traits
Chris@16:     reference operator[](difference_type d) const { return *(*this+d); }
Chris@16: 
Chris@16:     bool            is_1d_traversable() const { return _p.is_1d_traversable(width()); }   // is there no gap at the end of each row?
Chris@16:     x_iterator&     x()                   { return _p.x(); }
Chris@16: 
Chris@16:     iterator_from_2d(){}
Chris@16:     iterator_from_2d(const Loc2& p, std::ptrdiff_t width, std::ptrdiff_t x=0, std::ptrdiff_t y=0) : _coords(x,y), _width(width), _p(p) {}
Chris@16:     iterator_from_2d(const iterator_from_2d& pit) : _coords(pit._coords), _width(pit._width), _p(pit._p) {}
Chris@16:     template <typename Loc> iterator_from_2d(const iterator_from_2d<Loc>& pit) : _coords(pit._coords), _width(pit._width), _p(pit._p) {}
Chris@16: 
Chris@16: private:
Chris@16:     template <typename Loc> friend class iterator_from_2d;
Chris@16:     friend class boost::iterator_core_access;
Chris@16:     reference dereference() const { return *_p; }
Chris@16:     void increment() {
Chris@16:         ++_coords.x;
Chris@16:         ++_p.x();
Chris@16:         if (_coords.x>=_width) {
Chris@16:             _coords.x=0;
Chris@16:             ++_coords.y;
Chris@16:             _p+=point_t(-_width,1);
Chris@16:         }           
Chris@16:     }
Chris@16:     void decrement() {
Chris@16:         --_coords.x;
Chris@16:         --_p.x();
Chris@16:         if (_coords.x<0) {
Chris@16:             _coords.x=_width-1;
Chris@16:             --_coords.y;
Chris@16:             _p+=point_t(_width,-1);
Chris@16:         }
Chris@16:     }
Chris@16: 
Chris@16:     GIL_FORCEINLINE void advance(difference_type d) {  
Chris@16:         if (_width==0) return;  // unfortunately we need to check for that. Default-constructed images have width of 0 and the code below will throw if executed.
Chris@16:         point_t delta;
Chris@16:         if (_coords.x+d>=0) {  // not going back to a previous row?
Chris@16:             delta.x=(_coords.x+(std::ptrdiff_t)d)%_width - _coords.x;
Chris@16:             delta.y=(_coords.x+(std::ptrdiff_t)d)/_width;
Chris@16:         } else {
Chris@16:             delta.x=(_coords.x+(std::ptrdiff_t)d*(1-_width))%_width -_coords.x;
Chris@16:             delta.y=-(_width-_coords.x-(std::ptrdiff_t)d-1)/_width;
Chris@16:         }   
Chris@16:         _p+=delta;
Chris@16:         _coords.x+=delta.x;
Chris@16:         _coords.y+=delta.y;
Chris@16:     }
Chris@16: 
Chris@16:     difference_type distance_to(const iterator_from_2d& it) const { 
Chris@16:         if (_width==0) return 0;
Chris@16:         return (it.y_pos()-_coords.y)*_width + (it.x_pos()-_coords.x);
Chris@16:     }
Chris@16: 
Chris@16:     bool equal(const iterator_from_2d& it) const {
Chris@16:         assert(_width==it.width());     // they must belong to the same image
Chris@16:         return _coords==it._coords && _p==it._p;
Chris@16:     }
Chris@16: 
Chris@16:     point2<std::ptrdiff_t> _coords;
Chris@16:     std::ptrdiff_t _width;
Chris@16:     Loc2 _p;
Chris@16: };
Chris@16: 
Chris@16: template <typename Loc> // Models PixelLocatorConcept
Chris@16: struct const_iterator_type<iterator_from_2d<Loc> > {
Chris@16:     typedef iterator_from_2d<typename Loc::const_t> type;
Chris@16: };
Chris@16: 
Chris@16: template <typename Loc> // Models PixelLocatorConcept
Chris@16: struct iterator_is_mutable<iterator_from_2d<Loc> > : public iterator_is_mutable<typename Loc::x_iterator> {};
Chris@16: 
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  HasDynamicXStepTypeConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename Loc>
Chris@16: struct dynamic_x_step_type<iterator_from_2d<Loc> > {
Chris@16:     typedef iterator_from_2d<typename dynamic_x_step_type<Loc>::type>  type;
Chris@16: };
Chris@16: 
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  PixelBasedConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename Loc> // Models PixelLocatorConcept
Chris@16: struct color_space_type<iterator_from_2d<Loc> > : public color_space_type<Loc> {};
Chris@16: 
Chris@16: template <typename Loc> // Models PixelLocatorConcept
Chris@16: struct channel_mapping_type<iterator_from_2d<Loc> > : public channel_mapping_type<Loc> {};
Chris@16: 
Chris@16: template <typename Loc> // Models PixelLocatorConcept
Chris@16: struct is_planar<iterator_from_2d<Loc> > : public is_planar<Loc> {};
Chris@16: 
Chris@16: template <typename Loc> // Models PixelLocatorConcept
Chris@16: struct channel_type<iterator_from_2d<Loc> > : public channel_type<Loc> {};
Chris@16: 
Chris@16: } }  // namespace boost::gil
Chris@16: 
Chris@16: #endif