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- // Boost.Geometry (aka GGL, Generic Geometry Library)
- // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
- // Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
- // Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
- // Use, modification and distribution is subject to the Boost Software License,
- // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
- // http://www.boost.org/LICENSE_1_0.txt)
- //
- // Custom Polygon Example
- #include <iostream>
- #include <boost/geometry/geometry.hpp>
- #include <boost/geometry/geometries/register/point.hpp>
- #include <boost/geometry/geometries/register/ring.hpp>
- struct my_point
- {
- my_point(double an_x = 0, double an_y = 0)
- : x(an_x)
- , y(an_y)
- {}
- double x, y;
- };
- struct my_ring : std::deque<my_point>
- {};
- // Define a struct of a polygon, having always two holes
- // (of course this can be implemented differently, usually
- // with a vector or deque, but it is just an exampe)
- struct my_polygon
- {
- // required for a polygon: an outer ring...
- my_ring boundary;
- // ... and a Boost.Range compatible inner ring collection
- boost::array<my_ring, 2> holes;
- // just for the sample
- std::string name;
- my_polygon(std::string const& n = "") : name(n) {}
- };
- // We can conveniently use macro's to register point and ring
- BOOST_GEOMETRY_REGISTER_POINT_2D(my_point, double, cs::cartesian, x, y)
- BOOST_GEOMETRY_REGISTER_RING(my_ring)
- // There is currently no registration macro for polygons
- // and besides that a boost::array<T,N> in a macro would
- // be very specific, so we show it "by hand":
- namespace boost { namespace geometry { namespace traits
- {
- template<> struct tag<my_polygon> { typedef polygon_tag type; };
- template<> struct ring_const_type<my_polygon> { typedef my_ring const& type; };
- template<> struct ring_mutable_type<my_polygon> { typedef my_ring& type; };
- template<> struct interior_const_type<my_polygon>
- {
- typedef boost::array<my_ring, 2> const& type;
- };
- template<> struct interior_mutable_type<my_polygon>
- {
- typedef boost::array<my_ring, 2>& type;
- };
- template<> struct exterior_ring<my_polygon>
- {
- static my_ring& get(my_polygon& p)
- {
- return p.boundary;
- }
- static my_ring const& get(my_polygon const& p)
- {
- return p.boundary;
- }
- };
- template<> struct interior_rings<my_polygon>
- {
- typedef boost::array<my_ring, 2> holes_type;
- static holes_type& get(my_polygon& p)
- {
- return p.holes;
- }
- static holes_type const& get(my_polygon const& p)
- {
- return p.holes;
- }
- };
- }}} // namespace boost::geometry::traits
- int main()
- {
- my_polygon p1("my polygon");
- // Fill it the my-way, triangle
- p1.boundary.push_back(my_point(2, 0));
- p1.boundary.push_back(my_point(1, 5));
- p1.boundary.push_back(my_point(7, 6));
- p1.boundary.push_back(my_point(2, 0));
- // Triangle
- p1.holes[0].push_back(my_point(2, 1));
- p1.holes[0].push_back(my_point(2.4, 2));
- p1.holes[0].push_back(my_point(1.9, 2));
- p1.holes[0].push_back(my_point(2, 1));
- // Box
- p1.holes[1].push_back(my_point(3, 3));
- p1.holes[1].push_back(my_point(4, 3));
- p1.holes[1].push_back(my_point(4, 4));
- p1.holes[1].push_back(my_point(3, 4));
- p1.holes[1].push_back(my_point(3, 3));
- std::cout << "Representation of " << p1.name << ": "
- << boost::geometry::dsv(p1) << std::endl;
- std::cout << "Area of " << p1.name << ": "
- << boost::geometry::area(p1) << std::endl;
- std::cout << "Perimeter of " << p1.name << ": "
- << boost::geometry::perimeter(p1) << std::endl;
- std::cout << "Centroid of " << p1.name << ": "
- << boost::geometry::dsv(boost::geometry::return_centroid<my_point>(p1)) << std::endl;
- return 0;
- }
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