ceph/src/boost/libs/geometry/doc/src/examples/algorithms/for_each_point_const.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 //[for_each_point_const
  11 //` Sample using for_each_point, using a function to list coordinates
  12
  13 #include <iostream>
  14
  15 #include <boost/geometry.hpp>
  16 #include <boost/geometry/geometries/point_xy.hpp>
  17 #include <boost/geometry/geometries/polygon.hpp>
  18
  19
  20 template <typename Point>
  21 void list_coordinates(Point const& p)
  22 {
  23     using boost::geometry::get;
  24     std::cout << "x = " << get<0>(p) << " y = " << get<1>(p) << std::endl;
  25 }
  26
  27 int main()
  28 {
  29     typedef boost::geometry::model::d2::point_xy<double> point;
  30     boost::geometry::model::polygon<point> poly;
  31     boost::geometry::read_wkt("POLYGON((0 0,0 4,4 0,0 0))", poly);
  32     boost::geometry::for_each_point(poly, list_coordinates<point>);
  33     return 0;
  34 }
  35
  36 //]
  37
  38
  39 //[for_each_point_const_output
  40 /*`
  41 Output:
  42 [pre
  43 x = 0 y = 0
  44 x = 0 y = 4
  45 x = 4 y = 0
  46 x = 0 y = 0
  47 ]
  48 */
  49 //]