1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2 
3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
4 
5 // Use, modification and distribution is subject to the Boost Software License,
6 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
7 // http://www.boost.org/LICENSE_1_0.txt)
8 
9 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_CONVERT_RING_HPP
10 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_CONVERT_RING_HPP
11 
12 
13 #include <boost/mpl/assert.hpp>
14 #include <boost/range.hpp>
15 #include <boost/range/algorithm/reverse.hpp>
16 
17 #include <boost/geometry/core/tags.hpp>
18 #include <boost/geometry/core/exterior_ring.hpp>
19 #include <boost/geometry/core/interior_rings.hpp>
20 #include <boost/geometry/algorithms/detail/ring_identifier.hpp>
21 
22 #include <boost/geometry/algorithms/convert.hpp>
23 
24 
25 namespace boost { namespace geometry
26 {
27 
28 
29 #ifndef DOXYGEN_NO_DETAIL
30 namespace detail { namespace overlay
31 {
32 
33 
34 template<typename Tag>
35 struct convert_ring
36 {
37     BOOST_MPL_ASSERT_MSG
38         (
39             false, NOT_OR_NOT_YET_IMPLEMENTED_FOR_THIS_GEOMETRY_TAG
40             , (types<Tag>)
41         );
42 };
43 
44 template<>
45 struct convert_ring<ring_tag>
46 {
47     template<typename Destination, typename Source>
applyboost::geometry::detail::overlay::convert_ring48     static inline void apply(Destination& destination, Source const& source,
49                 bool append, bool reverse)
50     {
51         if (! append)
52         {
53             geometry::convert(source, destination);
54             if (reverse)
55             {
56                 boost::reverse(destination);
57             }
58         }
59     }
60 };
61 
62 
63 template<>
64 struct convert_ring<polygon_tag>
65 {
66     template<typename Destination, typename Source>
applyboost::geometry::detail::overlay::convert_ring67     static inline void apply(Destination& destination, Source const& source,
68                 bool append, bool reverse)
69     {
70         if (! append)
71         {
72             geometry::convert(source, exterior_ring(destination));
73             if (reverse)
74             {
75                 boost::reverse(exterior_ring(destination));
76             }
77         }
78         else
79         {
80             // Avoid adding interior rings which are invalid
81             // because of its number of points:
82             std::size_t const min_num_points
83                     = core_detail::closure::minimum_ring_size
84                             <
85                                 geometry::closure<Destination>::value
86                             >::value;
87 
88             if (geometry::num_points(source) >= min_num_points)
89             {
90                 interior_rings(destination).resize(
91                             interior_rings(destination).size() + 1);
92                 geometry::convert(source, interior_rings(destination).back());
93                 if (reverse)
94                 {
95                     boost::reverse(interior_rings(destination).back());
96                 }
97             }
98         }
99     }
100 };
101 
102 
103 }} // namespace detail::overlay
104 #endif // DOXYGEN_NO_DETAIL
105 
106 
107 }} // namespace boost::geometry
108 
109 
110 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_CONVERT_RING_HPP
111