1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2 
3 // Copyright (c) 2015, Oracle and/or its affiliates.
4 
5 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
6 
7 // Licensed under the Boost Software License version 1.0.
8 // http://www.boost.org/users/license.html
9 
10 #ifndef BOOST_GEOMETRY_GEOMETRIES_HELPER_GEOMETRY_HPP
11 #define BOOST_GEOMETRY_GEOMETRIES_HELPER_GEOMETRY_HPP
12 
13 #include <boost/geometry/core/cs.hpp>
14 #include <boost/geometry/core/coordinate_dimension.hpp>
15 #include <boost/geometry/core/coordinate_type.hpp>
16 #include <boost/geometry/core/point_type.hpp>
17 #include <boost/geometry/core/tag.hpp>
18 #include <boost/geometry/core/tags.hpp>
19 
20 #include <boost/geometry/geometries/box.hpp>
21 #include <boost/geometry/geometries/point.hpp>
22 
23 #include <boost/geometry/algorithms/not_implemented.hpp>
24 
25 
26 namespace boost { namespace geometry
27 {
28 
29 namespace detail { namespace helper_geometries
30 {
31 
32 template <typename Geometry, typename CS_Tag = typename cs_tag<Geometry>::type>
33 struct default_units
34 {
35     typedef typename coordinate_system<Geometry>::type::units type;
36 };
37 
38 // The Cartesian coordinate system does not define the type units.
39 // For that reason the generic implementation for default_units cannot be used
40 // and specialization needs to be defined.
41 // Moreover, it makes sense to define the units for the Cartesian
42 // coordinate system to be radians, as this way a Cartesian point can
43 // potentially be used in algorithms taking non-Cartesian strategies
44 // and work as if it was as point in the non-Cartesian coordinate
45 // system with radian units.
46 template <typename Geometry>
47 struct default_units<Geometry, cartesian_tag>
48 {
49     typedef radian type;
50 };
51 
52 
53 template <typename Units, typename CS_Tag>
54 struct cs_tag_to_coordinate_system
55 {
56     typedef cs::cartesian type;
57 };
58 
59 template <typename Units>
60 struct cs_tag_to_coordinate_system<Units, spherical_equatorial_tag>
61 {
62     typedef cs::spherical_equatorial<Units> type;
63 };
64 
65 template <typename Units>
66 struct cs_tag_to_coordinate_system<Units, spherical_tag>
67 {
68     typedef cs::spherical<Units> type;
69 };
70 
71 template <typename Units>
72 struct cs_tag_to_coordinate_system<Units, geographic_tag>
73 {
74     typedef cs::geographic<Units> type;
75 };
76 
77 
78 template
79 <
80     typename Point,
81     typename NewCoordinateType,
82     typename NewUnits,
83     typename CS_Tag = typename cs_tag<Point>::type
84 >
85 struct helper_point
86 {
87     typedef model::point
88         <
89             NewCoordinateType,
90             dimension<Point>::value,
91             typename cs_tag_to_coordinate_system<NewUnits, CS_Tag>::type
92         > type;
93 };
94 
95 
96 }} // detail::helper_geometries
97 
98 
99 namespace detail_dispatch
100 {
101 
102 
103 template
104 <
105     typename Geometry,
106     typename NewCoordinateType,
107     typename NewUnits,
108     typename Tag = typename tag<Geometry>::type>
109 struct helper_geometry : not_implemented<Geometry>
110 {};
111 
112 
113 template <typename Point, typename NewCoordinateType, typename NewUnits>
114 struct helper_geometry<Point, NewCoordinateType, NewUnits, point_tag>
115 {
116     typedef typename detail::helper_geometries::helper_point
117         <
118             Point, NewCoordinateType, NewUnits
119         >::type type;
120 };
121 
122 
123 template <typename Box, typename NewCoordinateType, typename NewUnits>
124 struct helper_geometry<Box, NewCoordinateType, NewUnits, box_tag>
125 {
126     typedef model::box
127         <
128             typename helper_geometry
129                 <
130                     typename point_type<Box>::type, NewCoordinateType, NewUnits
131                 >::type
132         > type;
133 };
134 
135 
136 } // detail_dispatch
137 
138 
139 // Meta-function that provides a new helper geometry of the same kind as
140 // the input geometry and the same coordinate system type,
141 // but with a possibly different coordinate type and coordinate system units
142 template
143 <
144     typename Geometry,
145     typename NewCoordinateType = typename coordinate_type<Geometry>::type,
146     typename NewUnits = typename detail::helper_geometries::default_units
147         <
148             Geometry
149         >::type
150 >
151 struct helper_geometry
152 {
153     typedef typename detail_dispatch::helper_geometry
154         <
155             Geometry, NewCoordinateType, NewUnits
156         >::type type;
157 };
158 
159 
160 }} // namespace boost::geometry
161 
162 #endif // BOOST_GEOMETRY_GEOMETRIES_HELPER_GEOMETRY_HPP
163