1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2 
3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
4 // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
5 // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
6 
7 // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
8 // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
9 
10 // Use, modification and distribution is subject to the Boost Software License,
11 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
12 // http://www.boost.org/LICENSE_1_0.txt)
13 
14 #ifndef BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
15 #define BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
16 
17 
18 #include <boost/range.hpp>
19 
20 #include <boost/geometry/core/point_type.hpp>
21 #include <boost/geometry/views/detail/points_view.hpp>
22 #include <boost/geometry/algorithms/assign.hpp>
23 
24 
25 namespace boost { namespace geometry
26 {
27 
28 
29 /*!
30 \brief Makes a box behave like a ring or a range
31 \details Adapts a box to the Boost.Range concept, enabling the user to iterating
32     box corners. The box_view is registered as a Ring Concept
33 \tparam Box \tparam_geometry{Box}
34 \tparam Clockwise If true, walks in clockwise direction, otherwise
35     it walks in counterclockwise direction
36 \ingroup views
37 
38 \qbk{before.synopsis,
39 [heading Model of]
40 [link geometry.reference.concepts.concept_ring Ring Concept]
41 }
42 
43 \qbk{[include reference/views/box_view.qbk]}
44 */
45 template <typename Box, bool Clockwise = true>
46 struct box_view
47     : public detail::points_view
48         <
49             typename geometry::point_type<Box>::type,
50             5
51         >
52 {
53     typedef typename geometry::point_type<Box>::type point_type;
54 
55     /// Constructor accepting the box to adapt
box_viewboost::geometry::box_view56     explicit box_view(Box const& box)
57         : detail::points_view<point_type, 5>(copy_policy(box))
58     {}
59 
60 private :
61 
62     class copy_policy
63     {
64     public :
copy_policy(Box const & box)65         inline copy_policy(Box const& box)
66             : m_box(box)
67         {}
68 
apply(point_type * points) const69         inline void apply(point_type* points) const
70         {
71             // assign_box_corners_oriented requires a range
72             // an alternative for this workaround would be to pass a range here,
73             // e.g. use boost::array in points_view instead of c-array
74             std::pair<point_type*, point_type*> rng = std::make_pair(points, points + 5);
75             detail::assign_box_corners_oriented<!Clockwise>(m_box, rng);
76             points[4] = points[0];
77         }
78     private :
79         Box const& m_box;
80     };
81 
82 };
83 
84 
85 #ifndef DOXYGEN_NO_TRAITS_SPECIALIZATIONS
86 
87 // All views on boxes are handled as rings
88 namespace traits
89 {
90 
91 template<typename Box, bool Clockwise>
92 struct tag<box_view<Box, Clockwise> >
93 {
94     typedef ring_tag type;
95 };
96 
97 template<typename Box>
98 struct point_order<box_view<Box, false> >
99 {
100     static order_selector const value = counterclockwise;
101 };
102 
103 
104 template<typename Box>
105 struct point_order<box_view<Box, true> >
106 {
107     static order_selector const value = clockwise;
108 };
109 
110 }
111 
112 #endif // DOXYGEN_NO_TRAITS_SPECIALIZATIONS
113 
114 
115 }} // namespace boost::geometry
116 
117 
118 #endif // BOOST_GEOMETRY_VIEWS_BOX_VIEW_HPP
119