ceph/src/boost/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
  19 /// \ingroup PixelLocatorModel PixelBasedModel
  20 /// \brief A 2D locator over a virtual image
  21 /// Upon dereferencing, invokes a given function object passing it its coordinates.
  22 /// Models:
  23 ///   PixelLocatorConcept,
  24 ///   HasDynamicXStepTypeConcept,
  25 ///   HasDynamicYStepTypeConcept,
  26 ///   HasTransposedTypeConcept
  27 ///
  28 /// \tparam DerefFn Function object that given a point returns a reference.
  29 ///         Models PixelDereferenceAdaptorConcept.
  30 /// \tparam IsTransposed Indicates if locator should navigate in transposed mode.
  31 template <typename DerefFn, bool IsTransposed>
  32 class virtual_2d_locator
  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 {
  40     using this_t = virtual_2d_locator<DerefFn, IsTransposed>;
  41 public:
  42     using parent_t = pixel_2d_locator_base
  43         <
  44             virtual_2d_locator<DerefFn, IsTransposed>,
  45             position_iterator<DerefFn, IsTransposed>,
  46             position_iterator<DerefFn, 1-IsTransposed>
  47         >;
  48     using const_t = virtual_2d_locator<typename DerefFn::const_t, IsTransposed>;
  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     {
  60         using type = virtual_2d_locator<deref_compose<NewDerefFn, DerefFn>, IsTransposed>;
  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
  69     virtual_2d_locator(
  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
 113     /// Returns the y distance between two x_iterators given the difference of their x positions
 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
 120     /// \todo TODO: is there no gap at the end of each row?
 121     ///       i.e. can we use x_iterator to visit every pixel instead of nested loops?
 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
 136 /////////////////////////////
 137 //  PixelBasedConcept
 138 /////////////////////////////
 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
 164 /////////////////////////////
 165 //  HasDynamicXStepTypeConcept
 166 /////////////////////////////
 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
 174 /////////////////////////////
 175 //  HasDynamicYStepTypeConcept
 176 /////////////////////////////
 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
 184 /////////////////////////////
 185 //  HasTransposedTypeConcept
 186 /////////////////////////////
 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