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: 
Chris@16: #ifndef GIL_POSITION_ITERATOR_HPP
Chris@16: #define GIL_POSITION_ITERATOR_HPP
Chris@16: 
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: /// \file               
Chris@16: /// \brief Locator for virtual image views
Chris@16: /// \author Lubomir Bourdev and Hailin Jin \n
Chris@16: ///         Adobe Systems Incorporated
Chris@16: /// \date   2005-2007 \n Last updated on February 12, 2007
Chris@16: ///
Chris@16: ////////////////////////////////////////////////////////////////////////////////////////
Chris@16: 
Chris@16: #include <boost/iterator/iterator_facade.hpp>
Chris@16: #include "locator.hpp"
Chris@16: 
Chris@16: namespace boost { namespace gil {
Chris@16: 
Chris@16: /// \defgroup PixelIteratorModelVirtual position_iterator
Chris@16: /// \ingroup PixelIteratorModel
Chris@16: /// \brief An iterator that remembers its current X,Y position and invokes a function object with it upon dereferencing. Models PixelIteratorConcept, PixelBasedConcept, HasDynamicXStepTypeConcept. Used to create virtual image views. 
Chris@16: 
Chris@16: 
Chris@16: /// \brief An iterator that remembers its current X,Y position and invokes a function object with it upon dereferencing. Models PixelIteratorConcept. Used to create virtual image views.
Chris@16: ///    Models: StepIteratorConcept, PixelIteratorConcept, PixelBasedConcept, HasDynamicXStepTypeConcept
Chris@16: /// \ingroup PixelIteratorModelVirtual PixelBasedModel
Chris@16: template <typename Deref, // A function object that given a point returns a pixel reference. Models PixelDereferenceAdaptorConcept
Chris@16:           int Dim>        // the dimension to advance along
Chris@16: struct position_iterator : public iterator_facade<position_iterator<Deref,Dim>,
Chris@16:                                                   typename Deref::value_type,
Chris@16:                                                   std::random_access_iterator_tag,
Chris@16:                                                   typename Deref::reference,
Chris@16:                                                   typename Deref::argument_type::template axis<Dim>::coord_t> {
Chris@16:     typedef iterator_facade<position_iterator<Deref,Dim>,
Chris@16:                             typename Deref::value_type,
Chris@16:                             std::random_access_iterator_tag,
Chris@16:                             typename Deref::reference,
Chris@16:                             typename Deref::argument_type::template axis<Dim>::coord_t> parent_t;
Chris@16:     typedef typename parent_t::difference_type difference_type;
Chris@16:     typedef typename parent_t::reference       reference;
Chris@16:     typedef typename Deref::argument_type      point_t;
Chris@16: 
Chris@16:     position_iterator() {}
Chris@16:     position_iterator(const point_t& p, const point_t& step, const Deref& d) : _p(p), _step(step), _d(d) {}
Chris@16: 
Chris@16:     position_iterator(const position_iterator& p) : _p(p._p), _step(p._step), _d(p._d) {}
Chris@16:     template <typename D> position_iterator(const position_iterator<D,Dim>& p) : _p(p._p), _step(p._step), _d(p._d) {}
Chris@16:     position_iterator& operator=(const position_iterator& p) { _p=p._p; _d=p._d; _step=p._step; return *this; }
Chris@16: 
Chris@16:     const point_t&   pos()      const { return _p; }
Chris@16:     const point_t&   step()     const { return _step; }
Chris@16:     const Deref&     deref_fn() const { return _d; }
Chris@16: 
Chris@16:     void set_step(difference_type s) { _step[Dim]=s; }
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 { point_t p=_p; p[Dim]+=d*_step[Dim]; return _d(p); }
Chris@16: 
Chris@16: private:
Chris@16:     point_t _p, _step;
Chris@16:     Deref   _d;
Chris@16: 
Chris@16:     template <typename DE, int DI> friend struct position_iterator;
Chris@16:     friend class boost::iterator_core_access;
Chris@16:     reference dereference()     const { return _d(_p); }
Chris@16:     void increment()                  { _p[Dim]+=_step[Dim]; }
Chris@16:     void decrement()                  { _p[Dim]-=_step[Dim]; }
Chris@16:     void advance(difference_type d)   { _p[Dim]+=d*_step[Dim]; }
Chris@16: 
Chris@16:     difference_type distance_to(const position_iterator& it) const { return (it._p[Dim]-_p[Dim])/_step[Dim]; }
Chris@16:     bool equal(const position_iterator& it) const { return _p==it._p; }
Chris@16: };
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct const_iterator_type<position_iterator<Deref,Dim> > {
Chris@16:     typedef position_iterator<typename Deref::const_t,Dim> type;
Chris@16: };
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct iterator_is_mutable<position_iterator<Deref,Dim> > : public mpl::bool_<Deref::is_mutable> {
Chris@16: };
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  PixelBasedConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct color_space_type<position_iterator<Deref,Dim> > : public color_space_type<typename Deref::value_type> {};
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct channel_mapping_type<position_iterator<Deref,Dim> > : public channel_mapping_type<typename Deref::value_type> {};
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct is_planar<position_iterator<Deref,Dim> > : public mpl::false_ {};
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct channel_type<position_iterator<Deref,Dim> > : public channel_type<typename Deref::value_type> {};
Chris@16: 
Chris@16: /////////////////////////////
Chris@16: //  HasDynamicXStepTypeConcept
Chris@16: /////////////////////////////
Chris@16: 
Chris@16: template <typename Deref,int Dim> 
Chris@16: struct dynamic_x_step_type<position_iterator<Deref,Dim> > {
Chris@16:     typedef position_iterator<Deref,Dim> type;
Chris@16: };
Chris@16: 
Chris@16: } }  // namespace boost::gil
Chris@16: 
Chris@16: #endif