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position_iterator.hpp
//
// Copyright 2005-2007 Adobe Systems Incorporated
//
// Distributed under the Boost Software License, Version 1.0
// See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt
//
#ifndef BOOST_GIL_POSITION_ITERATOR_HPP
#define BOOST_GIL_POSITION_ITERATOR_HPP
#include <boost/gil/locator.hpp>
#include <boost/iterator/iterator_facade.hpp>
#include <type_traits>
namespace boost { namespace gil {
template <typename Deref, int Dim>
struct position_iterator : public iterator_facade<position_iterator<Deref,Dim>,
typename Deref::value_type,
std::random_access_iterator_tag,
typename Deref::reference,
typename Deref::argument_type::template axis<Dim>::coord_t> {
using parent_t = iterator_facade<position_iterator<Deref,Dim>,
typename Deref::value_type,
std::random_access_iterator_tag,
typename Deref::reference,
typename Deref::argument_type::template axis<Dim>::coord_t>;
using difference_type = typename parent_t::difference_type;
using reference = typename parent_t::reference;
using point_t = typename Deref::argument_type;
position_iterator() {}
position_iterator(point_t const& p, point_t const& step, Deref const& d) : _p(p), _step(step), _d(d) {}
position_iterator(position_iterator const& p) : _p(p._p), _step(p._step), _d(p._d) {}
template <typename D>
position_iterator(position_iterator<D,Dim> const& p) : _p(p._p), _step(p._step), _d(p._d) {}
auto operator=(position_iterator const& p) -> position_iterator&
{
_p=p._p;
_d=p._d;
_step=p._step;
return *this;
}
auto pos() const -> point_t const& { return _p; }
auto step() const -> point_t const& { return _step; }
auto deref_fn() const -> Deref const& { return _d; }
void set_step(difference_type s) { _step[Dim]=s; }
auto operator[](difference_type d) const -> reference
{
point_t p=_p;
p[Dim]+=d*_step[Dim];
return _d(p);
}
private:
point_t _p, _step;
Deref _d;
template <typename DE, int DI> friend struct position_iterator;
friend class boost::iterator_core_access;
reference dereference() const { return _d(_p); }
void increment() { _p[Dim]+=_step[Dim]; }
void decrement() { _p[Dim]-=_step[Dim]; }
void advance(difference_type d) { _p[Dim]+=d*_step[Dim]; }
difference_type distance_to(const position_iterator& it) const { return (it._p[Dim]-_p[Dim])/_step[Dim]; }
bool equal(const position_iterator& it) const { return _p==it._p; }
};
template <typename Deref,int Dim>
struct const_iterator_type<position_iterator<Deref,Dim> > {
using type = position_iterator<typename Deref::const_t,Dim>;
};
template <typename Deref, int Dim>
struct iterator_is_mutable<position_iterator<Deref, Dim>>
: std::integral_constant<bool, Deref::is_mutable>
{
};
// PixelBasedConcept
template <typename Deref,int Dim>
struct color_space_type<position_iterator<Deref,Dim> > : public color_space_type<typename Deref::value_type> {};
template <typename Deref,int Dim>
struct channel_mapping_type<position_iterator<Deref,Dim> > : public channel_mapping_type<typename Deref::value_type> {};
template <typename Deref,int Dim>
struct is_planar<position_iterator<Deref, Dim>> : std::false_type {};
template <typename Deref,int Dim>
struct channel_type<position_iterator<Deref,Dim> > : public channel_type<typename Deref::value_type> {};
// HasDynamicXStepTypeConcept
template <typename Deref,int Dim>
struct dynamic_x_step_type<position_iterator<Deref,Dim> > {
using type = position_iterator<Deref,Dim>;
};
} } // namespace boost::gil
#endif
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:31
std::equal
BOOST_FORCEINLINE bool equal(boost::gil::iterator_from_2d< Loc1 > first, boost::gil::iterator_from_2d< Loc1 > last, boost::gil::iterator_from_2d< Loc2 > first2)
std::equal(I1,I1,I2) with I1 and I2 being a iterator_from_2d
Definition: algorithm.hpp:1087
boost::gil::position_iterator::operator[]
auto operator[](difference_type d) const -> reference
Definition: position_iterator.hpp:68
boost::gil::point< std::ptrdiff_t >