ceph/src/boost/libs/geometry/doc/src/examples/algorithms/assign_points.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 //[assign_points
  11 //` Shows usage of Boost.Geometry's assign, Boost.Assign, and Boost.Range to assign ranges of a linestring
  12
  13 #include <iostream>
  14
  15 #include <boost/geometry.hpp>
  16 #include <boost/geometry/geometries/linestring.hpp>
  17 #include <boost/geometry/geometries/adapted/boost_tuple.hpp>
  18
  19 #include <boost/assign.hpp>
  20 #include <boost/geometry/geometries/adapted/boost_range/filtered.hpp>
  21
  22 BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian)
  23
  24 template <typename T>
  25 struct x_between
  26 {
  27     x_between(T a, T b)
  28         : fa(a), fb(b)
  29     {}
  30
  31     template <typename P>
  32     bool operator()(P const& p) const
  33     {
  34         return boost::geometry::get<0>(p) >= fa
  35             && boost::geometry::get<0>(p) <= fb;
  36     }
  37 private :
  38     T fa, fb;
  39 };
  40
  41
  42 int main()
  43 {
  44     using namespace boost::assign;
  45
  46     typedef boost::geometry::model::linestring<boost::tuple<int, int> > ls;
  47
  48     ls line1, line2, line3;
  49
  50     line1 = tuple_list_of(0, 0)(2, 3)(4, 0)(6, 3)(8, 0)(10, 3)(12, 0); /*< tuple_list_of is part of Boost.Assign and can be used for Boost.Geometry if points are tuples >*/
  51     boost::geometry::assign_points(line2, tuple_list_of(0, 0)(2, 2)(4, 0)(6, 2)(8, 0)); /*< tuple_list_of delivers a range and can therefore be used in boost::geometry::assign >*/
  52     boost::geometry::assign_points(line3, line1 | boost::adaptors::filtered(x_between<int>(4, 8))); /*< Boost.Range adaptors can also be used in boost::geometry::assign >*/
  53
  54     std::cout << "line 1: " << boost::geometry::dsv(line1) << std::endl;
  55     std::cout << "line 2: " << boost::geometry::dsv(line2) << std::endl;
  56     std::cout << "line 3: " << boost::geometry::dsv(line3) << std::endl;
  57
  58     return 0;
  59 }
  60
  61 //]
  62
  63
  64 //[assign_points_output
  65 /*`
  66 Output:
  67 [pre
  68 line 1: ((0, 0), (2, 3), (4, 0), (6, 3), (8, 0), (10, 3), (12, 0))
  69 line 2: ((0, 0), (2, 2), (4, 0), (6, 2), (8, 0))
  70 line 3: ((4, 0), (6, 3), (8, 0))
  71 ]
  72 */
  73 //]