Generic Image Library: position_iterator.hpp Source File

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position_iterator.hpp
1//
2// Copyright 2005-2007 Adobe Systems Incorporated
3//
4// Distributed under the Boost Software License, Version 1.0
5// See accompanying file LICENSE_1_0.txt or copy at
6// http://www.boost.org/LICENSE_1_0.txt
7//
8#ifndef BOOST_GIL_POSITION_ITERATOR_HPP
9#define BOOST_GIL_POSITION_ITERATOR_HPP
10
11#include <boost/gil/locator.hpp>
12
13#include <boost/iterator/iterator_facade.hpp>
14
15#include <type_traits>
16
17namespace boost { namespace gil {
18
23
30template <typename Deref, int Dim>
31 struct position_iterator : public iterator_facade<position_iterator<Deref,Dim>,
32 typename Deref::value_type,
33 std::random_access_iterator_tag,
34 typename Deref::reference,
35 typename Deref::argument_type::template axis<Dim>::coord_t> {
36 using parent_t = iterator_facade<position_iterator<Deref,Dim>,
37 typename Deref::value_type,
38 std::random_access_iterator_tag,
39 typename Deref::reference,
40 typename Deref::argument_type::template axis<Dim>::coord_t>;
41 using difference_type = typename parent_t::difference_type;
42 using reference = typename parent_t::reference;
43 using point_t = typename Deref::argument_type;
44
45 position_iterator() {}
46 position_iterator(point_t const& p, point_t const& step, Deref const& d) : _p(p), _step(step), _d(d) {}
47
48 position_iterator(position_iterator const& p) : _p(p._p), _step(p._step), _d(p._d) {}
49
50 template <typename D>
51 position_iterator(position_iterator<D,Dim> const& p) : _p(p._p), _step(p._step), _d(p._d) {}
52
53 auto operator=(position_iterator const& p) -> position_iterator&
54 {
55 _p=p._p;
56 _d=p._d;
57 _step=p._step;
58 return *this;
59 }
60
61 auto pos() const -> point_t const& { return _p; }
62 auto step() const -> point_t const& { return _step; }
63 auto deref_fn() const -> Deref const& { return _d; }
64
65 void set_step(difference_type s) { _step[Dim]=s; }
68 auto operator[](difference_type d) const -> reference
69 {
70 point_t p=_p;
71 p[Dim]+=d*_step[Dim];
72 return _d(p);
73 }
74
75private:
76 point_t _p, _step;
77 Deref _d;
78
79 template <typename DE, int DI> friend struct position_iterator;
80 friend class boost::iterator_core_access;
81 reference dereference() const { return _d(_p); }
82 void increment() { _p[Dim]+=_step[Dim]; }
83 void decrement() { _p[Dim]-=_step[Dim]; }
84 void advance(difference_type d) { _p[Dim]+=d*_step[Dim]; }
85
86 difference_type distance_to(const position_iterator& it) const { return (it._p[Dim]-_p[Dim])/_step[Dim]; }
87 bool equal(const position_iterator& it) const { return _p==it._p; }
88};
89
90template <typename Deref,int Dim>
91struct const_iterator_type<position_iterator<Deref,Dim> > {
92 using type = position_iterator<typename Deref::const_t,Dim>;
93};
94
95template <typename Deref, int Dim>
96struct iterator_is_mutable<position_iterator<Deref, Dim>>
97 : std::integral_constant<bool, Deref::is_mutable>
98{
99};
100
102// PixelBasedConcept
104
105template <typename Deref,int Dim>
106struct color_space_type<position_iterator<Deref,Dim> > : public color_space_type<typename Deref::value_type> {};
107
108template <typename Deref,int Dim>
109struct channel_mapping_type<position_iterator<Deref,Dim> > : public channel_mapping_type<typename Deref::value_type> {};
110
111template <typename Deref,int Dim>
112struct is_planar<position_iterator<Deref, Dim>> : std::false_type {};
113
114template <typename Deref,int Dim>
115struct channel_type<position_iterator<Deref,Dim> > : public channel_type<typename Deref::value_type> {};
116
118// HasDynamicXStepTypeConcept
120
121template <typename Deref,int Dim>
122struct dynamic_x_step_type<position_iterator<Deref,Dim> > {
123 using type = position_iterator<Deref,Dim>;
124};
125
126} } // namespace boost::gil
127
128#endif
boost::gil::point< std::ptrdiff_t >
boost
defined(BOOST_NO_CXX17_HDR_MEMORY_RESOURCE)
Definition: algorithm.hpp:36
boost::gil::position_iterator
An iterator that remembers its current X,Y position and invokes a function object with it upon derefe...
Definition: position_iterator.hpp:35
boost::gil::position_iterator::operator[]
auto operator[](difference_type d) const -> reference
Definition: position_iterator.hpp:68