1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2 // QuickBook Example
3
4 // Copyright (c) 2015, Oracle and/or its affiliates
5
6 // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
7
8 // Licensed under the Boost Software License version 1.0.
9 // http://www.boost.org/users/license.html
10
11 //[is_valid_failure
12 //` Checks whether a geometry is valid and, if not valid, checks if it could be fixed by bg::correct; if so bg::correct is called on the geometry
13
14 #include <iostream>
15
16 #include <boost/geometry.hpp>
17 #include <boost/geometry/geometries/point_xy.hpp>
18 #include <boost/geometry/geometries/polygon.hpp>
19 /*<-*/ #include "create_svg_one.hpp" /*->*/
20
main()21 int main()
22 {
23 typedef boost::geometry::model::d2::point_xy<double> point_type;
24 typedef boost::geometry::model::polygon<point_type> polygon_type;
25
26 polygon_type poly;
27 boost::geometry::read_wkt("POLYGON((0 0,0 10,10 10,10 0),(0 0,9 2,9 1,0 0),(0 0,2 9,1 9,0 0))", poly);
28
29 std::cout << "original geometry: " << boost::geometry::dsv(poly) << std::endl;
30 boost::geometry::validity_failure_type failure;
31 bool valid = boost::geometry::is_valid(poly, failure);
32
33 // if the invalidity is only due to lack of closing points and/or wrongly oriented rings, then bg::correct can fix it
34 bool could_be_fixed = (failure == boost::geometry::failure_not_closed
35 || boost::geometry::failure_wrong_orientation);
36 std::cout << "is valid? " << (valid ? "yes" : "no") << std::endl;
37 if (! valid)
38 {
39 std::cout << "can boost::geometry::correct remedy invalidity? " << (could_be_fixed ? "possibly yes" : "no") << std::endl;
40 if (could_be_fixed)
41 {
42 boost::geometry::correct(poly);
43 std::cout << "after correction: " << (boost::geometry::is_valid(poly) ? "valid" : "still invalid") << std::endl;
44 std::cout << "corrected geometry: " << boost::geometry::dsv(poly) << std::endl;
45 }
46 }
47 /*<-*/ create_svg("is_valid_failure_example.svg", poly); /*->*/
48 return 0;
49 }
50
51 //]
52
53 //[is_valid_failure_output
54 /*`
55 Output:
56 [pre
57 original geometry: (((0, 0), (0, 10), (10, 10), (10, 0)), ((0, 0), (9, 2), (9, 1), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))
58 is valid? no
59 can boost::geometry::correct remedy invalidity? possibly yes
60 after correction: valid
61 corrected geometry: (((0, 0), (0, 10), (10, 10), (10, 0), (0, 0)), ((0, 0), (9, 1), (9, 2), (0, 0)), ((0, 0), (2, 9), (1, 9), (0, 0)))
62
63 [$img/algorithms/is_valid_failure_example.png]
64
65 ]
66
67 */
68 //]
69
