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

   1 // Boost.Geometry
   2 // QuickBook Example
   3
   4 // Copyright (c) 2011-2012 Barend Gehrels, Amsterdam, the Netherlands.
   5 // Copyright (c) 2015 Adam Wulkiewicz, Lodz, Poland.
   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 //[ring
  12 //` Declaration and use of the Boost.Geometry model::ring, modelling the Ring Concept
  13
  14 #include <iostream>
  15 #include <boost/geometry.hpp>
  16 #include <boost/geometry/geometries/geometries.hpp>
  17
  18 namespace bg = boost::geometry;
  19
  20 int main()
  21 {
  22     typedef bg::model::point<double, 2, bg::cs::cartesian> point_t;
  23     typedef bg::model::ring<point_t> ring_t; /*< Default parameters, clockwise, closed ring. >*/
  24
  25     ring_t ring1; /*< Default-construct a ring. >*/
  26
  27 #if !defined(BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX) \
  28  && !defined(BOOST_NO_CXX11_HDR_INITIALIZER_LIST)
  29
  30     ring_t ring2{{0.0, 0.0}, {0.0, 5.0}, {5.0, 5.0}, {5.0, 0.0}, {0.0, 0.0}}; /*< Construct a ring containing four points plus one closing point, using C++11 unified initialization syntax. >*/
  31
  32 #endif
  33
  34     bg::append(ring1, point_t(0.0, 0.0)); /*< Append point. >*/
  35     bg::append(ring1, point_t(0.0, 5.0));
  36     bg::append(ring1, point_t(5.0, 5.0));
  37     bg::append(ring1, point_t(5.0, 0.0));
  38     bg::append(ring1, point_t(0.0, 0.0));
  39
  40     double a = bg::area(ring1);
  41
  42     std::cout << a << std::endl;
  43
  44     return 0;
  45 }
  46
  47 //]
  48
  49
  50 //[ring_output
  51 /*`
  52 Output:
  53 [pre
  54 25
  55 ]
  56 */
  57 //]