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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 | //[reverse | |
11 | //` Shows how to reverse a ring or polygon | |
12 | ||
13 | #include <iostream> | |
14 | ||
15 | #include <boost/geometry.hpp> | |
16 | #include <boost/geometry/geometries/polygon.hpp> | |
17 | #include <boost/geometry/geometries/ring.hpp> | |
18 | #include <boost/geometry/geometries/adapted/boost_tuple.hpp> | |
19 | ||
20 | BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian) | |
21 | ||
22 | #include <boost/assign.hpp> | |
23 | ||
24 | int main() | |
25 | { | |
26 | using boost::assign::tuple_list_of; | |
27 | ||
28 | typedef boost::tuple<int, int> point; | |
29 | typedef boost::geometry::model::polygon<point> polygon; | |
30 | typedef boost::geometry::model::ring<point> ring; | |
31 | ||
32 | ||
33 | polygon poly; | |
34 | boost::geometry::exterior_ring(poly) = tuple_list_of(0, 0)(0, 9)(10, 10)(0, 0); | |
35 | boost::geometry::interior_rings(poly).push_back(tuple_list_of(1, 2)(4, 6)(2, 8)(1, 2)); | |
36 | ||
37 | double area_before = boost::geometry::area(poly); | |
38 | boost::geometry::reverse(poly); | |
39 | double area_after = boost::geometry::area(poly); | |
40 | std::cout << boost::geometry::dsv(poly) << std::endl; | |
41 | std::cout << area_before << " -> " << area_after << std::endl; | |
42 | ||
43 | ring r = tuple_list_of(0, 0)(0, 9)(8, 8)(0, 0); | |
44 | ||
45 | area_before = boost::geometry::area(r); | |
46 | boost::geometry::reverse(r); | |
47 | area_after = boost::geometry::area(r); | |
48 | std::cout << boost::geometry::dsv(r) << std::endl; | |
49 | std::cout << area_before << " -> " << area_after << std::endl; | |
50 | ||
51 | return 0; | |
52 | } | |
53 | ||
54 | //] | |
55 | ||
56 | ||
57 | //[reverse_output | |
58 | /*` | |
59 | Output: | |
60 | [pre | |
61 | (((0, 0), (10, 10), (0, 9), (0, 0)), ((1, 2), (2, 8), (4, 6), (1, 2))) | |
62 | 38 -> -38 | |
63 | ((0, 0), (8, 8), (0, 9), (0, 0)) | |
64 | 36 -> -36 | |
65 | ] | |
66 | */ | |
67 | //] |