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 // Copyright (c) 2014 Adam Wulkiewicz, Lodz, Poland.
7 
8 // This file was modified by Oracle on 2014.
9 // Modifications copyright (c) 2014 Oracle and/or its affiliates.
10 
11 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
12 
13 // Use, modification and distribution is subject to the Boost Software License,
14 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
15 // http://www.boost.org/LICENSE_1_0.txt)
16 
17 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_CENTROID_TRANSLATING_TRANSFORMER_HPP
18 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_CENTROID_TRANSLATING_TRANSFORMER_HPP
19 
20 
21 #include <cstddef>
22 
23 #include <boost/core/addressof.hpp>
24 #include <boost/core/ref.hpp>
25 
26 #include <boost/geometry/core/cs.hpp>
27 #include <boost/geometry/core/tag_cast.hpp>
28 #include <boost/geometry/core/tags.hpp>
29 #include <boost/geometry/core/point_type.hpp>
30 
31 #include <boost/geometry/arithmetic/arithmetic.hpp>
32 
33 #include <boost/geometry/iterators/point_iterator.hpp>
34 
35 
36 namespace boost { namespace geometry
37 {
38 
39 #ifndef DOXYGEN_NO_DETAIL
40 namespace detail { namespace centroid
41 {
42 
43 
44 // NOTE: There is no need to translate in other coordinate systems than
45 // cartesian. But if it was needed then one should translate using
46 // CS-specific technique, e.g. in spherical/geographic a translation
47 // vector should contain coordinates being multiplies of 2PI or 360 deg.
48 template <typename Geometry,
49           typename CastedTag = typename tag_cast
50                                 <
51                                     typename tag<Geometry>::type,
52                                     areal_tag
53                                 >::type,
54     typename CSTag = typename cs_tag<Geometry>::type>
55 struct translating_transformer
56 {
57     typedef typename geometry::point_type<Geometry>::type point_type;
58     typedef boost::reference_wrapper<point_type const> result_type;
59 
translating_transformerboost::geometry::detail::centroid::translating_transformer60     explicit translating_transformer(Geometry const&) {}
translating_transformerboost::geometry::detail::centroid::translating_transformer61     explicit translating_transformer(point_type const&) {}
62 
applyboost::geometry::detail::centroid::translating_transformer63     result_type apply(point_type const& pt) const
64     {
65         return result_type(pt);
66     }
67 
68     template <typename ResPt>
apply_reverseboost::geometry::detail::centroid::translating_transformer69     void apply_reverse(ResPt &) const {}
70 };
71 
72 // Specialization for Areal Geometries in cartesian CS
73 template <typename Geometry>
74 struct translating_transformer<Geometry, areal_tag, cartesian_tag>
75 {
76     typedef typename geometry::point_type<Geometry>::type point_type;
77     typedef point_type result_type;
78 
translating_transformerboost::geometry::detail::centroid::translating_transformer79     explicit translating_transformer(Geometry const& geom)
80         : m_origin(NULL)
81     {
82         geometry::point_iterator<Geometry const>
83             pt_it = geometry::points_begin(geom);
84         if ( pt_it != geometry::points_end(geom) )
85         {
86             m_origin = boost::addressof(*pt_it);
87         }
88     }
89 
translating_transformerboost::geometry::detail::centroid::translating_transformer90     explicit translating_transformer(point_type const& origin)
91         : m_origin(boost::addressof(origin))
92     {}
93 
applyboost::geometry::detail::centroid::translating_transformer94     result_type apply(point_type const& pt) const
95     {
96         point_type res = pt;
97         if ( m_origin )
98             geometry::subtract_point(res, *m_origin);
99         return res;
100     }
101 
102     template <typename ResPt>
apply_reverseboost::geometry::detail::centroid::translating_transformer103     void apply_reverse(ResPt & res_pt) const
104     {
105         if ( m_origin )
106             geometry::add_point(res_pt, *m_origin);
107     }
108 
109     const point_type * m_origin;
110 };
111 
112 
113 }} // namespace detail::centroid
114 #endif // DOXYGEN_NO_DETAIL
115 
116 }} // namespace boost::geometry
117 
118 
119 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_CENTROID_TRANSLATING_TRANSFORMER_HPP
120