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_VIRTUAL_LOCATOR_HPP
14#define GIL_VIRTUAL_LOCATOR_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 "position_iterator.hpp"
27
28namespace boost { namespace gil {
29
30/// \brief A 2D locator over a virtual image. Upon dereferencing, invokes a given function object passing it its coordinates. Models: PixelLocatorConcept, HasDynamicXStepTypeConcept, HasDynamicYStepTypeConcept, HasTransposedTypeConcept
31/// \ingroup PixelLocatorModel PixelBasedModel
32///
33template <typename Deref, bool IsTransposed> // A function object that given a point returns a reference. Models PixelDereferenceAdaptorConcept
34class virtual_2d_locator : public pixel_2d_locator_base<virtual_2d_locator<Deref,IsTransposed>, position_iterator<Deref,IsTransposed>, position_iterator<Deref,1-IsTransposed> > {
35 typedef virtual_2d_locator<Deref,IsTransposed> this_t;
36public:
37 typedef pixel_2d_locator_base<virtual_2d_locator<Deref,IsTransposed>, position_iterator<Deref,IsTransposed>, position_iterator<Deref,1-IsTransposed> > parent_t;
38 typedef virtual_2d_locator<typename Deref::const_t,IsTransposed> const_t;
39
40 typedef Deref deref_fn_t;
41 typedef typename parent_t::point_t point_t;
42
43 typedef typename parent_t::coord_t coord_t;
44 typedef typename parent_t::x_coord_t x_coord_t;
45 typedef typename parent_t::y_coord_t y_coord_t;
46 typedef typename parent_t::x_iterator x_iterator;
47 typedef typename parent_t::y_iterator y_iterator;
48
49 template <typename NewDeref> struct add_deref {
50 typedef virtual_2d_locator<deref_compose<NewDeref,Deref>,IsTransposed > type;
51 static type make(const virtual_2d_locator<Deref,IsTransposed>& loc, const NewDeref& nderef) {
52 return type(loc.pos(), loc.step(), deref_compose<NewDeref,Deref>(nderef,loc.deref_fn()));
53 }
54 };
55
56 virtual_2d_locator(const point_t& p=point_t(0,0), const point_t& step=point_t(1,1), const deref_fn_t& d=deref_fn_t()) : _p(p,step,d) {}
57 template <typename D, bool TR> virtual_2d_locator(const virtual_2d_locator<D,TR>& loc, coord_t y_step)
58 : _p(loc.pos(), point_t(loc.step().x,loc.step().y*y_step), loc.deref_fn()) {}
59 template <typename D, bool TR> virtual_2d_locator(const virtual_2d_locator<D,TR>& loc, coord_t x_step, coord_t y_step, bool transpose=false)
60 : _p(loc.pos(), transpose ?
61 point_t(loc.step().x*y_step,loc.step().y*x_step) :
62 point_t(loc.step().x*x_step,loc.step().y*y_step), loc.deref_fn()) { assert(transpose==(IsTransposed!=TR));}
63
64 template <typename D, bool TR> virtual_2d_locator(const virtual_2d_locator<D,TR>& pl) : _p(pl._p) {}
65 virtual_2d_locator(const virtual_2d_locator& pl) : _p(pl._p) {}
66
67 bool operator==(const this_t& p) const { return _p==p._p; }
68
69 x_iterator& x() { return *gil_reinterpret_cast<x_iterator*>(this); }
70 y_iterator& y() { return _p; }
71 x_iterator const& x() const { return *gil_reinterpret_cast_c<x_iterator const*>(this); }
72 y_iterator const& y() const { return _p; }
73
74 // Returns the y distance between two x_iterators given the difference of their x positions
75 y_coord_t y_distance_to(const this_t& it2, x_coord_t xDiff) const { return (it2.pos()[1-IsTransposed] - pos()[1-IsTransposed])/step()[1-IsTransposed]; }
76 bool is_1d_traversable(x_coord_t) const { return false; } // is there no gap at the end of each row? I.e. can we use x_iterator to visit every pixel instead of nested loops?
77
78 // Methods specific for virtual 2D locator
79 const point_t& pos() const { return _p.pos(); }
80 const point_t& step() const { return _p.step(); }
81 const deref_fn_t& deref_fn() const { return _p.deref_fn(); }
82private:
83 template <typename D, bool TR> friend class virtual_2d_locator;
84 y_iterator _p; // contains the current position, the step and the dereference object
85};
86
87/////////////////////////////
88// PixelBasedConcept
89/////////////////////////////
90
91template <typename D, bool TR>
92struct channel_type<virtual_2d_locator<D,TR> > : public channel_type<typename virtual_2d_locator<D,TR>::parent_t> {
93};
94
95template <typename D, bool TR>
96struct color_space_type<virtual_2d_locator<D,TR> > : public color_space_type<typename virtual_2d_locator<D,TR>::parent_t> {
97};
98
99template <typename D, bool TR>
100struct channel_mapping_type<virtual_2d_locator<D,TR> > : public channel_mapping_type<typename virtual_2d_locator<D,TR>::parent_t> {
101};
102
103template <typename D, bool TR>
104struct is_planar<virtual_2d_locator<D,TR> > : public is_planar<typename virtual_2d_locator<D,TR>::parent_t> {
105};
106
107/////////////////////////////
108// HasDynamicXStepTypeConcept
109/////////////////////////////
110
111template <typename D, bool TR>
112struct dynamic_x_step_type<virtual_2d_locator<D,TR> > {
113 typedef virtual_2d_locator<D,TR> type;
114};
115
116/////////////////////////////
117// HasDynamicYStepTypeConcept
118/////////////////////////////
119
120template <typename D, bool TR>
121struct dynamic_y_step_type<virtual_2d_locator<D,TR> > {
122 typedef virtual_2d_locator<D,TR> type;
123};
124
125/////////////////////////////
126// HasTransposedTypeConcept
127/////////////////////////////
128
129template <typename D, bool IsTransposed>
130struct transposed_type<virtual_2d_locator<D,IsTransposed> > {
131 typedef virtual_2d_locator<D,1-IsTransposed> type;
132};
133
134} } // namespace boost::gil
135
136#endif
137

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