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73 lines
2.2 KiB
C++
73 lines
2.2 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2011 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2011 Mateusz Loskot, London, UK.
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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//
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// Custom triangle template Example
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#include <iostream>
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#include <boost/array.hpp>
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#include <boost/tuple/tuple.hpp>
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#include <boost/geometry/algorithms/area.hpp>
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#include <boost/geometry/algorithms/centroid.hpp>
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#include <boost/geometry/geometries/adapted/boost_tuple.hpp>
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#include <boost/geometry/geometries/register/ring.hpp>
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#include <boost/geometry/strategies/strategies.hpp>
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#include <boost/geometry/util/write_dsv.hpp>
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BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS(cs::cartesian);
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template <typename P>
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struct triangle : public boost::array<P, 3>
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{
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};
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// Register triangle<P> as a ring
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namespace boost { namespace geometry {
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template <typename P> struct tag<triangle<P> > { typedef ring_tag type; }
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}}
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namespace boost { namespace geometry { namespace dispatch {
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// Specializations of area dispatch structure, implement algorithm
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template<typename P, typename S>
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struct area<ring_tag, triangle<P>, S>
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{
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static inline double apply(triangle<P> const& t, S const&)
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{
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return 0.5 * ((get<0>(t[1]) - get<0>(t[0])) * (get<1>(t[2]) - get<1>(t[0]))
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- (get<0>(t[2]) - get<0>(t[0])) * (get<1>(t[1]) - get<1>(t[0])));
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}
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};
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}}} // namespace boost::geometry::dispatch
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int main()
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{
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//triangle<boost::geometry::point_xy<double> > t;
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triangle<boost::tuple<double, double> > t;
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t[0] = boost::make_tuple(0, 0);
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t[1] = boost::make_tuple(5, 0);
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t[2] = boost::make_tuple(2.5, 2.5);
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std::cout << "Triangle: " << boost::geometry::dsv(t) << std::endl;
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std::cout << "Area: " << boost::geometry::area(t) << std::endl;
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//boost::geometry::point_xy<double> c;
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boost::tuple<double, double> c;
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boost::geometry::centroid(t, c);
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std::cout << "Centroid: " << boost::geometry::dsv(c) << std::endl;
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return 0;
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}
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