ceph/src/boost/libs/geometry/doc/src/examples/geometries/register/ring.cpp

   1 // Boost.Geometry (aka GGL, Generic Geometry Library)
   2 // QuickBook Example
   3
   4 // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
   5
   6 // Use, modification and distribution is subject to the Boost Software License,
   7 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
   8 // http://www.boost.org/LICENSE_1_0.txt)
   9
  10 //[register_ring
  11 //` Show the use of the macro BOOST_GEOMETRY_REGISTER_RING
  12
  13 #include <iostream>
  14
  15 #include <boost/geometry.hpp>
  16 #include <boost/geometry/geometries/point_xy.hpp>
  17 #include <boost/geometry/geometries/register/ring.hpp>
  18
  19 typedef boost::geometry::model::d2::point_xy<double> point_2d;
  20
  21 BOOST_GEOMETRY_REGISTER_RING(std::vector<point_2d>) /*< The magic: adapt vector to Boost.Geometry Ring Concept >*/
  22
  23 int main()
  24 {
  25     // Normal usage of std::
  26     std::vector<point_2d> ring;
  27     ring.push_back(point_2d(1, 1));
  28     ring.push_back(point_2d(2, 2));
  29     ring.push_back(point_2d(2, 1));
  30
  31
  32     // Usage of Boost.Geometry
  33     boost::geometry::correct(ring);
  34     std::cout << "Area: "  << boost::geometry::area(ring) << std::endl;
  35     std::cout << "WKT: "  << boost::geometry::wkt(ring) << std::endl;
  36
  37     return 0;
  38 }
  39
  40 //]
  41
  42
  43 //[register_ring_output
  44 /*`
  45 Output:
  46 [pre
  47 Area: 0.5
  48 WKT: POLYGON((1 1,2 2,2 1,1 1))
  49 ]
  50 */
  51 //]