Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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BOOST_GEOMETRY_REGISTER_RING

Macro to register a ring.

Description

The macro BOOST_GEOMETRY_REGISTER_RING registers a ring such that it is recognized by Boost.Geometry and that Boost.Geometry functionality can used with the specified type. The ring may contain template parameters, which must be specified then.

Synopsis

#define BOOST_GEOMETRY_REGISTER_RING(Ring)

Parameters

Name

Description

Ring

ring type to be registered

Header

#include <boost/geometry/geometries/register/ring.hpp>

Example

Show the use of the macro BOOST_GEOMETRY_REGISTER_RING

#include <iostream>

#include <boost/geometry.hpp>
#include <boost/geometry/geometries/point_xy.hpp>
#include <boost/geometry/geometries/register/ring.hpp>

typedef boost::geometry::model::d2::point_xy<double> point_2d;

BOOST_GEOMETRY_REGISTER_RING(std::vector<point_2d>) 1

int main()
{
    // Normal usage of std::
    std::vector<point_2d> ring;
    ring.push_back(point_2d(1, 1));
    ring.push_back(point_2d(2, 2));
    ring.push_back(point_2d(2, 1));
    
    
    // Usage of Boost.Geometry
    boost::geometry::correct(ring);
    std::cout << "Area: "  << boost::geometry::area(ring) << std::endl;
    std::cout << "WKT: "  << boost::geometry::wkt(ring) << std::endl;
    
    return 0;
}

1

The magic: adapt vector to Boost.Geometry Ring Concept

Output:

Area: 0.5
WKT: POLYGON((1 1,2 2,2 1,1 1))

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