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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 | //[boost_range_filtered | |
11 | //` Shows how to use a Boost.Geometry linestring, filtered by Boost.Range adaptor | |
12 | ||
13 | #include <iostream> | |
14 | ||
15 | #include <boost/geometry.hpp> | |
16 | #include <boost/geometry/geometries/linestring.hpp> | |
17 | #include <boost/geometry/geometries/point_xy.hpp> | |
18 | #include <boost/geometry/geometries/adapted/boost_range/filtered.hpp> | |
19 | ||
20 | struct not_two | |
21 | { | |
22 | template <typename P> | |
23 | bool operator()(P const& p) const | |
24 | { | |
25 | return boost::geometry::get<1>(p) != 2; | |
26 | } | |
27 | }; | |
28 | ||
29 | ||
30 | int main() | |
31 | { | |
32 | typedef boost::geometry::model::d2::point_xy<int> xy; | |
33 | boost::geometry::model::linestring<xy> line; | |
34 | line.push_back(xy(0, 0)); | |
35 | line.push_back(xy(1, 1)); | |
36 | line.push_back(xy(2, 2)); | |
37 | line.push_back(xy(3, 1)); | |
38 | line.push_back(xy(4, 0)); | |
39 | line.push_back(xy(5, 1)); | |
40 | line.push_back(xy(6, 2)); | |
41 | line.push_back(xy(7, 1)); | |
42 | line.push_back(xy(8, 0)); | |
43 | ||
44 | using boost::adaptors::filtered; | |
45 | std::cout | |
46 | << boost::geometry::length(line) << std::endl | |
47 | << boost::geometry::length(line | filtered(not_two())) << std::endl | |
48 | << boost::geometry::dsv(line | filtered(not_two())) << std::endl; | |
49 | ||
50 | return 0; | |
51 | } | |
52 | ||
53 | //] | |
54 | ||
55 | //[boost_range_filtered_output | |
56 | /*` | |
57 | Output: | |
58 | [pre | |
59 | 11.3137 | |
60 | 9.65685 | |
61 | ((0, 0), (1, 1), (3, 1), (4, 0), (5, 1), (7, 1), (8, 0)) | |
62 | ] | |
63 | */ | |
64 | //] |