1/*
2 Copyright 2005-2007 Adobe Systems Incorporated
3
4 Use, modification and distribution are subject to the Boost Software License,
5 Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
6 http://www.boost.org/LICENSE_1_0.txt).
7
8 See http://opensource.adobe.com/gil for most recent version including documentation.
9*/
10
11/*************************************************************************************************/
12
13#ifndef GIL_POSITION_ITERATOR_HPP
14#define GIL_POSITION_ITERATOR_HPP
15
16////////////////////////////////////////////////////////////////////////////////////////
17/// \file
18/// \brief Locator for virtual image views
19/// \author Lubomir Bourdev and Hailin Jin \n
20/// Adobe Systems Incorporated
21/// \date 2005-2007 \n Last updated on February 12, 2007
22///
23////////////////////////////////////////////////////////////////////////////////////////
24
25#include <boost/iterator/iterator_facade.hpp>
26#include "locator.hpp"
27
28namespace boost { namespace gil {
29
30/// \defgroup PixelIteratorModelVirtual position_iterator
31/// \ingroup PixelIteratorModel
32/// \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.
33
34
35/// \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.
36/// Models: StepIteratorConcept, PixelIteratorConcept, PixelBasedConcept, HasDynamicXStepTypeConcept
37/// \ingroup PixelIteratorModelVirtual PixelBasedModel
38template <typename Deref, // A function object that given a point returns a pixel reference. Models PixelDereferenceAdaptorConcept
39 int Dim> // the dimension to advance along
40struct position_iterator : public iterator_facade<position_iterator<Deref,Dim>,
41 typename Deref::value_type,
42 std::random_access_iterator_tag,
43 typename Deref::reference,
44 typename Deref::argument_type::template axis<Dim>::coord_t> {
45 typedef iterator_facade<position_iterator<Deref,Dim>,
46 typename Deref::value_type,
47 std::random_access_iterator_tag,
48 typename Deref::reference,
49 typename Deref::argument_type::template axis<Dim>::coord_t> parent_t;
50 typedef typename parent_t::difference_type difference_type;
51 typedef typename parent_t::reference reference;
52 typedef typename Deref::argument_type point_t;
53
54 position_iterator() {}
55 position_iterator(const point_t& p, const point_t& step, const Deref& d) : _p(p), _step(step), _d(d) {}
56
57 position_iterator(const position_iterator& p) : _p(p._p), _step(p._step), _d(p._d) {}
58 template <typename D> position_iterator(const position_iterator<D,Dim>& p) : _p(p._p), _step(p._step), _d(p._d) {}
59 position_iterator& operator=(const position_iterator& p) { _p=p._p; _d=p._d; _step=p._step; return *this; }
60
61 const point_t& pos() const { return _p; }
62 const point_t& step() const { return _step; }
63 const Deref& deref_fn() const { return _d; }
64
65 void set_step(difference_type s) { _step[Dim]=s; }
66 /// For some reason operator[] provided by iterator_adaptor returns a custom class that is convertible to reference
67 /// We require our own reference because it is registered in iterator_traits
68 reference operator[](difference_type d) const { point_t p=_p; p[Dim]+=d*_step[Dim]; return _d(p); }
69
70private:
71 point_t _p, _step;
72 Deref _d;
73
74 template <typename DE, int DI> friend struct position_iterator;
75 friend class boost::iterator_core_access;
76 reference dereference() const { return _d(_p); }
77 void increment() { _p[Dim]+=_step[Dim]; }
78 void decrement() { _p[Dim]-=_step[Dim]; }
79 void advance(difference_type d) { _p[Dim]+=d*_step[Dim]; }
80
81 difference_type distance_to(const position_iterator& it) const { return (it._p[Dim]-_p[Dim])/_step[Dim]; }
82 bool equal(const position_iterator& it) const { return _p==it._p; }
83};
84
85template <typename Deref,int Dim>
86struct const_iterator_type<position_iterator<Deref,Dim> > {
87 typedef position_iterator<typename Deref::const_t,Dim> type;
88};
89
90template <typename Deref,int Dim>
91struct iterator_is_mutable<position_iterator<Deref,Dim> > : public mpl::bool_<Deref::is_mutable> {
92};
93
94/////////////////////////////
95// PixelBasedConcept
96/////////////////////////////
97
98template <typename Deref,int Dim>
99struct color_space_type<position_iterator<Deref,Dim> > : public color_space_type<typename Deref::value_type> {};
100
101template <typename Deref,int Dim>
102struct channel_mapping_type<position_iterator<Deref,Dim> > : public channel_mapping_type<typename Deref::value_type> {};
103
104template <typename Deref,int Dim>
105struct is_planar<position_iterator<Deref,Dim> > : public mpl::false_ {};
106
107template <typename Deref,int Dim>
108struct channel_type<position_iterator<Deref,Dim> > : public channel_type<typename Deref::value_type> {};
109
110/////////////////////////////
111// HasDynamicXStepTypeConcept
112/////////////////////////////
113
114template <typename Deref,int Dim>
115struct dynamic_x_step_type<position_iterator<Deref,Dim> > {
116 typedef position_iterator<Deref,Dim> type;
117};
118
119} } // namespace boost::gil
120
121#endif
122

source code of boost/boost/gil/position_iterator.hpp