Boost GIL


virtual_locator.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_VIRTUAL_LOCATOR_HPP
9 #define BOOST_GIL_VIRTUAL_LOCATOR_HPP
10 
11 #include <boost/gil/dynamic_step.hpp>
12 #include <boost/gil/position_iterator.hpp>
13 
14 #include <boost/assert.hpp>
15 #include <boost/iterator/iterator_facade.hpp>
16 
17 namespace boost { namespace gil {
18 
31 template <typename DerefFn, bool IsTransposed>
33  : public pixel_2d_locator_base
34  <
35  virtual_2d_locator<DerefFn, IsTransposed>,
36  position_iterator<DerefFn, IsTransposed>,
37  position_iterator<DerefFn, 1-IsTransposed>
38  >
39 {
41 public:
43  <
46  position_iterator<DerefFn, 1-IsTransposed>
47  >;
49  using deref_fn_t = DerefFn;
50  using point_t = typename parent_t::point_t;
51  using coord_t = typename parent_t::coord_t;
52  using x_coord_t = typename parent_t::x_coord_t;
53  using y_coord_t = typename parent_t::y_coord_t;
54  using x_iterator = typename parent_t::x_iterator;
55  using y_iterator = typename parent_t::y_iterator;
56 
57  template <typename NewDerefFn>
58  struct add_deref
59  {
61 
62  static type make(this_t const& loc, NewDerefFn const& new_deref_fn)
63  {
64  return type(loc.pos(), loc.step(),
65  deref_compose<NewDerefFn, DerefFn>(new_deref_fn, loc.deref_fn()));
66  }
67  };
68 
70  point_t const& p = {0, 0},
71  point_t const& step = {1, 1},
72  deref_fn_t const& deref_fn = deref_fn_t())
73  : y_pos_(p, step, deref_fn)
74  {}
75 
76  template <typename D, bool TR>
77  virtual_2d_locator(virtual_2d_locator<D, TR> const &loc, coord_t y_step)
78  : y_pos_(loc.pos(), point_t(loc.step().x, loc.step().y * y_step), loc.deref_fn())
79  {}
80 
81  template <typename D, bool TR>
82  virtual_2d_locator(virtual_2d_locator<D, TR> const& loc, coord_t x_step, coord_t y_step, bool transpose = false)
83  : y_pos_(loc.pos()
84  , transpose ?
85  point_t(loc.step().x * y_step, loc.step().y * x_step) :
86  point_t(loc.step().x * x_step, loc.step().y * y_step)
87  , loc.deref_fn())
88  {
89  BOOST_ASSERT(transpose == (IsTransposed != TR));
90  }
91 
92  template <typename D, bool TR>
93  virtual_2d_locator(virtual_2d_locator<D, TR> const& other) : y_pos_(other.y_pos_) {}
94 
95  virtual_2d_locator(virtual_2d_locator const& other) : y_pos_(other.y_pos_) {}
96  virtual_2d_locator& operator=(virtual_2d_locator const& other) = default;
97 
98  bool operator==(const this_t& p) const { return y_pos_ == p.y_pos_; }
99 
100  auto x() -> x_iterator&
101  {
102  return *gil_reinterpret_cast<x_iterator*>(this);
103  }
104 
105  auto x() const -> x_iterator const&
106  {
107  return *gil_reinterpret_cast_c<x_iterator const*>(this);
108  }
109 
110  auto y() -> y_iterator& { return y_pos_; }
111  auto y() const -> y_iterator const& { return y_pos_; }
112 
114  auto y_distance_to(this_t const& it2, x_coord_t) const -> y_coord_t
115  {
116  return (it2.pos()[1 - IsTransposed] - pos()[1 - IsTransposed])
117  / step()[1 - IsTransposed];
118  }
119 
122  bool is_1d_traversable(x_coord_t) const { return false; }
123 
124  // Methods specific for virtual 2D locator
125  auto pos() const -> point_t const& { return y_pos_.pos(); }
126  auto step() const -> point_t const& { return y_pos_.step(); }
127  auto deref_fn() const -> deref_fn_t const& { return y_pos_.deref_fn(); }
128 
129 private:
130  template <typename D, bool TR>
131  friend class virtual_2d_locator;
132 
133  y_iterator y_pos_; // current position, the step and the dereference object
134 };
135 
137 // PixelBasedConcept
139 
140 template <typename D, bool TR>
141 struct channel_type<virtual_2d_locator<D, TR>>
142  : channel_type<typename virtual_2d_locator<D, TR>::parent_t>
143 {
144 };
145 
146 template <typename D, bool TR>
147 struct color_space_type<virtual_2d_locator<D, TR>>
148  : color_space_type<typename virtual_2d_locator<D, TR>::parent_t>
149 {
150 };
151 
152 template <typename D, bool TR>
153 struct channel_mapping_type<virtual_2d_locator<D, TR>>
154  : channel_mapping_type<typename virtual_2d_locator<D, TR>::parent_t>
155 {
156 };
157 
158 template <typename D, bool TR>
159 struct is_planar<virtual_2d_locator<D, TR>>
160  : is_planar<typename virtual_2d_locator<D, TR>::parent_t>
161 {
162 };
163 
165 // HasDynamicXStepTypeConcept
167 
168 template <typename D, bool TR>
169 struct dynamic_x_step_type<virtual_2d_locator<D,TR>>
170 {
171  using type = virtual_2d_locator<D,TR>;
172 };
173 
175 // HasDynamicYStepTypeConcept
177 
178 template <typename D, bool TR>
179 struct dynamic_y_step_type<virtual_2d_locator<D,TR>>
180 {
181  using type = virtual_2d_locator<D,TR>;
182 };
183 
185 // HasTransposedTypeConcept
187 
188 template <typename D, bool IsTransposed>
189 struct transposed_type<virtual_2d_locator<D,IsTransposed>>
190 {
191  using type = virtual_2d_locator<D,1-IsTransposed>;
192 };
193 
194 }} // namespace boost::gil
195 
196 #endif
base class for models of PixelLocatorConceptPixel locator is similar to a pixel iterator,...
Definition: locator.hpp:109
An iterator that remembers its current X,Y position and invokes a function object with it upon derefe...
Definition: position_iterator.hpp:31
A 2D locator over a virtual image Upon dereferencing, invokes a given function object passing it its ...
Definition: virtual_locator.hpp:32
auto y_distance_to(this_t const &it2, x_coord_t) const -> y_coord_t
Returns the y distance between two x_iterators given the difference of their x positions.
Definition: virtual_locator.hpp:114
bool is_1d_traversable(x_coord_t) const
Definition: virtual_locator.hpp:122
Composes two dereference function objects. Similar to std::unary_compose but needs to pull some alias...
Definition: utilities.hpp:121
2D point both axes of which have the same dimension typeModels: Point2DConcept
Definition: locator.hpp:28