/Src/Dependencies/Boost/libs/geometry/doc/src/examples/algorithms/difference_inserter.cpp

 1// Boost.Geometry (aka GGL, Generic Geometry Library)
 2// QuickBook Example
 3
 4// Copyright (c) 2011 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//[difference_inserter
11//` Shows how the difference_inserter function can be used
12
13#include <iostream>
14#include <vector>
15
16#include <boost/geometry.hpp>
17#include <boost/geometry/geometries/point_xy.hpp>
18#include <boost/geometry/geometries/polygon.hpp>
19#include <boost/geometry/domains/gis/io/wkt/wkt.hpp>
20
21#include <boost/foreach.hpp>
22/*<-*/ #include "create_svg_overlay.hpp" /*->*/
23
24int main()
25{
26    typedef boost::geometry::model::polygon<boost::geometry::model::d2::point_xy<double> > polygon;
27
28    polygon green, blue;
29
30    boost::geometry::read_wkt(
31        "POLYGON((2 1.3,2.4 1.7,2.8 1.8,3.4 1.2,3.7 1.6,3.4 2,4.1 3,5.3 2.6,5.4 1.2,4.9 0.8,2.9 0.7,2 1.3)"
32            "(4.0 2.0, 4.2 1.4, 4.8 1.9, 4.4 2.2, 4.0 2.0))", green);
33
34    boost::geometry::read_wkt(
35        "POLYGON((4.0 -0.5 , 3.5 1.0 , 2.0 1.5 , 3.5 2.0 , 4.0 3.5 , 4.5 2.0 , 6.0 1.5 , 4.5 1.0 , 4.0 -0.5))", blue);
36
37    std::vector<polygon> output;
38
39    // Note that this sample simulates the symmetric difference,
40    // which is also available as a separate algorithm.
41    // It chains the output iterator returned by the function to the second instance.
42    boost::geometry::difference_inserter<polygon>
43        (
44            green, blue,
45                boost::geometry::difference_inserter<polygon>
46                    (
47                        blue, green,
48                        std::back_inserter(output)
49                    )
50        );
51
52
53    int i = 0;
54    std::cout << "(blue \ green) u (green \ blue):" << std::endl;
55    BOOST_FOREACH(polygon const& p, output)
56    {
57        std::cout << i++ << ": " << boost::geometry::area(p) << std::endl;
58    }
59
60    /*<-*/ create_svg("difference_inserter.svg", green, blue, output); /*->*/
61    return 0;
62}
63
64//]
65
66
67//[difference_inserter_output
68/*`
69Output:
70[pre
71(blue \\ green) u (green \\ blue):
720: 0.525154
731: 0.015
742: 0.181136
753: 0.128798
764: 0.340083
775: 0.307778
786: 0.02375
797: 0.542951
808: 0.0149697
819: 0.226855
8210: 0.839424
83
84[$img/algorithms/sym_difference.png]
85
86]
87*/
88//]