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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 triangle template Example
- #include <iostream>
- #include <boost/array.hpp>
- #include <boost/tuple/tuple.hpp>
- #include <boost/geometry/algorithms/area.hpp>
- #include <boost/geometry/algorithms/centroid.hpp>
- #include <boost/geometry/geometries/adapted/boost_tuple.hpp>
- #include <boost/geometry/geometries/register/ring.hpp>
- #include <boost/geometry/strategies/strategies.hpp>
- #include <boost/geometry/io/dsv/write.hpp>
- BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian)
- template <typename P>
- struct triangle : public boost::array<P, 3>
- {
- };
- // Register triangle<P> as a ring
- BOOST_GEOMETRY_REGISTER_RING_TEMPLATED(triangle)
- namespace boost { namespace geometry { namespace dispatch {
- // Specializations of area dispatch structure, implement algorithm
- template<typename Point>
- struct area<triangle<Point>, ring_tag>
- {
- template <typename Strategy>
- static inline double apply(triangle<Point> const& t, Strategy const&)
- {
- return 0.5 * ((get<0>(t[1]) - get<0>(t[0])) * (get<1>(t[2]) - get<1>(t[0]))
- - (get<0>(t[2]) - get<0>(t[0])) * (get<1>(t[1]) - get<1>(t[0])));
- }
- };
- }}} // namespace boost::geometry::dispatch
- int main()
- {
- //triangle<boost::geometry::point_xy<double> > t;
- triangle<boost::tuple<double, double> > t;
- t[0] = boost::make_tuple(0, 0);
- t[1] = boost::make_tuple(5, 0);
- t[2] = boost::make_tuple(2.5, 2.5);
- std::cout << "Triangle: " << boost::geometry::dsv(t) << std::endl;
- std::cout << "Area: " << boost::geometry::area(t) << std::endl;
- //boost::geometry::point_xy<double> c;
- boost::tuple<double, double> c;
- boost::geometry::centroid(t, c);
- std::cout << "Centroid: " << boost::geometry::dsv(c) << std::endl;
- return 0;
- }
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