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