// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
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// Copyright (c) 2009-2015 Barend Gehrels, Amsterdam, the Netherlands.
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// This file was modified by Oracle on 2015.
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// Modifications copyright (c) 2015, Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
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// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
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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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#ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
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#define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
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#include <boost/math/special_functions/fpclassify.hpp>
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#include <boost/numeric/conversion/cast.hpp>
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#include <boost/geometry/algorithms/detail/distance/interface.hpp>
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#include <boost/geometry/algorithms/detail/distance/point_to_geometry.hpp>
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#include <boost/geometry/arithmetic/arithmetic.hpp>
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#include <boost/geometry/util/for_each_coordinate.hpp>
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#include <boost/geometry/util/select_most_precise.hpp>
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#include <boost/geometry/strategies/centroid.hpp>
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#include <boost/geometry/strategies/default_distance_result.hpp>
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// Helper geometry
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#include <boost/geometry/geometries/point.hpp>
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namespace boost { namespace geometry
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{
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namespace strategy { namespace centroid
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{
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namespace detail
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{
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template <typename Type, std::size_t DimensionCount>
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struct weighted_length_sums
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{
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typedef typename geometry::model::point
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<
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Type, DimensionCount,
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cs::cartesian
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> work_point;
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Type length;
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work_point average_sum;
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inline weighted_length_sums()
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: length(Type())
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{
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geometry::assign_zero(average_sum);
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}
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};
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}
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template
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<
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typename Point,
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typename PointOfSegment = Point
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>
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class weighted_length
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{
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private :
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typedef typename select_most_precise
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<
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typename default_distance_result<Point>::type,
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typename default_distance_result<PointOfSegment>::type
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>::type distance_type;
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public :
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typedef detail::weighted_length_sums
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<
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distance_type,
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geometry::dimension<Point>::type::value
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> state_type;
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static inline void apply(PointOfSegment const& p1,
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PointOfSegment const& p2, state_type& state)
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{
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distance_type const d = geometry::distance(p1, p2);
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state.length += d;
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typename state_type::work_point weighted_median;
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geometry::assign_zero(weighted_median);
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geometry::add_point(weighted_median, p1);
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geometry::add_point(weighted_median, p2);
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geometry::multiply_value(weighted_median, d/2);
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geometry::add_point(state.average_sum, weighted_median);
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}
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static inline bool result(state_type const& state, Point& centroid)
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{
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distance_type const zero = distance_type();
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if (! geometry::math::equals(state.length, zero)
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&& boost::math::isfinite(state.length)) // Prevent NaN centroid coordinates
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{
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// NOTE: above distance_type is checked, not the centroid coordinate_type
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// which means that the centroid can still be filled with INF
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// if e.g. distance_type is double and centroid contains floats
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geometry::for_each_coordinate(centroid, set_sum_div_length(state));
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return true;
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}
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return false;
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}
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struct set_sum_div_length
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{
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state_type const& m_state;
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set_sum_div_length(state_type const& state)
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: m_state(state)
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{}
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template <typename Pt, std::size_t Dimension>
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void apply(Pt & centroid) const
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{
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typedef typename geometry::coordinate_type<Pt>::type coordinate_type;
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geometry::set<Dimension>(
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centroid,
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boost::numeric_cast<coordinate_type>(
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geometry::get<Dimension>(m_state.average_sum) / m_state.length
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)
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);
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}
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};
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};
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#ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
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namespace services
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{
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// Register this strategy for linear geometries, in all dimensions
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template <std::size_t N, typename Point, typename Geometry>
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struct default_strategy
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<
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cartesian_tag,
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linear_tag,
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N,
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Point,
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Geometry
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>
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{
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typedef weighted_length
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<
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Point,
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typename point_type<Geometry>::type
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> type;
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};
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} // namespace services
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#endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
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}} // namespace strategy::centroid
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
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