ceph/src/boost/boost/geometry/formulas/flattening.hpp

   1 // Boost.Geometry
   2
   3 // Copyright (c) 2014-2016 Oracle and/or its affiliates.
   4
   5 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
   6
   7 // Use, modification and distribution is subject to the Boost Software License,
   8 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   9 // http://www.boost.org/LICENSE_1_0.txt)
  10
  11 #ifndef BOOST_GEOMETRY_FORMULAS_FLATTENING_HPP
  12 #define BOOST_GEOMETRY_FORMULAS_FLATTENING_HPP
  13
  14 #include <boost/geometry/core/radius.hpp>
  15 #include <boost/geometry/core/tag.hpp>
  16 #include <boost/geometry/core/tags.hpp>
  17
  18 #include <boost/geometry/algorithms/not_implemented.hpp>
  19
  20 namespace boost { namespace geometry
  21 {
  22
  23 #ifndef DOXYGEN_NO_DISPATCH
  24 namespace formula_dispatch
  25 {
  26
  27 template <typename ResultType, typename Geometry, typename Tag = typename tag<Geometry>::type>
  28 struct flattening
  29     : not_implemented<Tag>
  30 {};
  31
  32 template <typename ResultType, typename Geometry>
  33 struct flattening<ResultType, Geometry, srs_sphere_tag>
  34 {
  35     static inline ResultType apply(Geometry const& /*geometry*/)
  36     {
  37         return ResultType(0);
  38     }
  39 };
  40
  41 template <typename ResultType, typename Geometry>
  42 struct flattening<ResultType, Geometry, srs_spheroid_tag>
  43 {
  44     static inline ResultType apply(Geometry const& geometry)
  45     {
  46         // (a - b) / a
  47         return ResultType(get_radius<0>(geometry) - get_radius<2>(geometry))
  48                     / ResultType(get_radius<0>(geometry));
  49     }
  50 };
  51
  52 } // namespace formula_dispatch
  53 #endif // DOXYGEN_NO_DISPATCH
  54
  55 #ifndef DOXYGEN_NO_DETAIL
  56 namespace formula
  57 {
  58
  59 template <typename ResultType, typename Geometry>
  60 ResultType flattening(Geometry const& geometry)
  61 {
  62     return formula_dispatch::flattening<ResultType, Geometry>::apply(geometry);
  63 }
  64
  65 } // namespace formula
  66 #endif // DOXYGEN_NO_DETAIL
  67
  68 }} // namespace boost::geometry
  69
  70 #endif // BOOST_GEOMETRY_FORMULAS_FLATTENING_HPP