ceph/src/boost/libs/geometry/doc/src/examples/algorithms/is_valid_message.cpp

   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_message
  12 //` Checks whether a geometry is valid and, if not valid, prints a message describing the reason
  13
  14 #include <iostream>
  15 #include <string>
  16
  17 #include <boost/geometry.hpp>
  18 #include <boost/geometry/geometries/point_xy.hpp>
  19 #include <boost/geometry/geometries/polygon.hpp>
  20 /*<-*/ #include "create_svg_one.hpp" /*->*/
  21
  22 int main()
  23 {
  24     typedef boost::geometry::model::d2::point_xy<double> point_type;
  25     typedef boost::geometry::model::polygon<point_type> polygon_type;
  26
  27     polygon_type poly;
  28     boost::geometry::read_wkt("POLYGON((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),(2 9,9 2,9 9,2 9))", poly);
  29
  30     std::string message;
  31     bool valid = boost::geometry::is_valid(poly, message);
  32     std::cout << "is valid? " << (valid ? "yes" : "no") << std::endl;
  33     if (! valid)
  34     {
  35         std::cout << "why not valid? " << message << std::endl;
  36     }
  37     /*<-*/ create_svg("is_valid_example.svg", poly); /*->*/
  38     return 0;
  39 }
  40
  41 //]
  42
  43 //[is_valid_message_output
  44 /*`
  45 Output:
  46 [pre
  47 is valid? no
  48 why not valid? Geometry has disconnected interior
  49
  50 [$img/algorithms/is_valid_example.png]
  51
  52 ]
  53
  54 */
  55 //]