vn-verdnaturachat/ios/Pods/boost-for-react-native/boost/gil/position_iterator.hpp

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5.6 KiB
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/*
Copyright 2005-2007 Adobe Systems Incorporated
Use, modification and distribution are subject to 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).
See http://opensource.adobe.com/gil for most recent version including documentation.
*/
/*************************************************************************************************/
#ifndef GIL_POSITION_ITERATOR_HPP
#define GIL_POSITION_ITERATOR_HPP
////////////////////////////////////////////////////////////////////////////////////////
/// \file
/// \brief Locator for virtual image views
/// \author Lubomir Bourdev and Hailin Jin \n
/// Adobe Systems Incorporated
/// \date 2005-2007 \n Last updated on February 12, 2007
///
////////////////////////////////////////////////////////////////////////////////////////
#include <boost/iterator/iterator_facade.hpp>
#include "locator.hpp"
namespace boost { namespace gil {
/// \defgroup PixelIteratorModelVirtual position_iterator
/// \ingroup PixelIteratorModel
/// \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.
/// \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.
/// Models: StepIteratorConcept, PixelIteratorConcept, PixelBasedConcept, HasDynamicXStepTypeConcept
/// \ingroup PixelIteratorModelVirtual PixelBasedModel
template <typename Deref, // A function object that given a point returns a pixel reference. Models PixelDereferenceAdaptorConcept
int Dim> // the dimension to advance along
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> {
typedef 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> parent_t;
typedef typename parent_t::difference_type difference_type;
typedef typename parent_t::reference reference;
typedef typename Deref::argument_type point_t;
position_iterator() {}
position_iterator(const point_t& p, const point_t& step, const Deref& d) : _p(p), _step(step), _d(d) {}
position_iterator(const position_iterator& p) : _p(p._p), _step(p._step), _d(p._d) {}
template <typename D> position_iterator(const position_iterator<D,Dim>& p) : _p(p._p), _step(p._step), _d(p._d) {}
position_iterator& operator=(const position_iterator& p) { _p=p._p; _d=p._d; _step=p._step; return *this; }
const point_t& pos() const { return _p; }
const point_t& step() const { return _step; }
const Deref& deref_fn() const { return _d; }
void set_step(difference_type s) { _step[Dim]=s; }
/// For some reason operator[] provided by iterator_adaptor returns a custom class that is convertible to reference
/// We require our own reference because it is registered in iterator_traits
reference operator[](difference_type d) const { 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> > {
typedef position_iterator<typename Deref::const_t,Dim> type;
};
template <typename Deref,int Dim>
struct iterator_is_mutable<position_iterator<Deref,Dim> > : public mpl::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> > : public mpl::false_ {};
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> > {
typedef position_iterator<Deref,Dim> type;
};
} } // namespace boost::gil
#endif