// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2015 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
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// This file was modified by Oracle on 2014, 2015.
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// Modifications copyright (c) 2014-2015 Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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// Contributed and/or modified by Menelaos Karavelas, 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_ALGORITHMS_CONVEX_HULL_HPP
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#define BOOST_GEOMETRY_ALGORITHMS_CONVEX_HULL_HPP
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#include <boost/array.hpp>
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#include <boost/variant/apply_visitor.hpp>
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#include <boost/variant/static_visitor.hpp>
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#include <boost/variant/variant_fwd.hpp>
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#include <boost/geometry/core/cs.hpp>
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#include <boost/geometry/core/point_order.hpp>
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#include <boost/geometry/core/closure.hpp>
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#include <boost/geometry/core/exterior_ring.hpp>
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#include <boost/geometry/geometries/concepts/check.hpp>
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#include <boost/geometry/strategies/convex_hull.hpp>
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#include <boost/geometry/strategies/concepts/convex_hull_concept.hpp>
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#include <boost/geometry/strategies/default_strategy.hpp>
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#include <boost/geometry/util/condition.hpp>
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#include <boost/geometry/views/detail/range_type.hpp>
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#include <boost/geometry/algorithms/is_empty.hpp>
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#include <boost/geometry/algorithms/detail/as_range.hpp>
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#include <boost/geometry/algorithms/detail/assign_box_corners.hpp>
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namespace boost { namespace geometry
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{
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#ifndef DOXYGEN_NO_DETAIL
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namespace detail { namespace convex_hull
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{
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template <order_selector Order, closure_selector Closure>
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struct hull_insert
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{
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// Member template function (to avoid inconvenient declaration
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// of output-iterator-type, from hull_to_geometry)
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template <typename Geometry, typename OutputIterator, typename Strategy>
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static inline OutputIterator apply(Geometry const& geometry,
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OutputIterator out, Strategy const& strategy)
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{
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typename Strategy::state_type state;
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strategy.apply(geometry, state);
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strategy.result(state, out, Order == clockwise, Closure != open);
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return out;
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}
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};
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struct hull_to_geometry
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{
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template <typename Geometry, typename OutputGeometry, typename Strategy>
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static inline void apply(Geometry const& geometry, OutputGeometry& out,
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Strategy const& strategy)
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{
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hull_insert
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<
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geometry::point_order<OutputGeometry>::value,
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geometry::closure<OutputGeometry>::value
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>::apply(geometry,
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range::back_inserter(
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// Handle linestring, ring and polygon the same:
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detail::as_range
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<
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typename range_type<OutputGeometry>::type
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>(out)), strategy);
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}
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};
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}} // namespace detail::convex_hull
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#endif // DOXYGEN_NO_DETAIL
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#ifndef DOXYGEN_NO_DISPATCH
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namespace dispatch
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{
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template
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<
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typename Geometry,
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typename Tag = typename tag<Geometry>::type
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>
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struct convex_hull
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: detail::convex_hull::hull_to_geometry
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{};
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template <typename Box>
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struct convex_hull<Box, box_tag>
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{
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template <typename OutputGeometry, typename Strategy>
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static inline void apply(Box const& box, OutputGeometry& out,
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Strategy const& )
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{
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static bool const Close
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= geometry::closure<OutputGeometry>::value == closed;
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static bool const Reverse
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= geometry::point_order<OutputGeometry>::value == counterclockwise;
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// A hull for boxes is trivial. Any strategy is (currently) skipped.
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boost::array<typename point_type<Box>::type, 4> range;
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geometry::detail::assign_box_corners_oriented<Reverse>(box, range);
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geometry::append(out, range);
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if (BOOST_GEOMETRY_CONDITION(Close))
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{
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geometry::append(out, *boost::begin(range));
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}
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}
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};
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template <order_selector Order, closure_selector Closure>
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struct convex_hull_insert
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: detail::convex_hull::hull_insert<Order, Closure>
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{};
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} // namespace dispatch
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#endif // DOXYGEN_NO_DISPATCH
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namespace resolve_strategy {
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struct convex_hull
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{
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template <typename Geometry, typename OutputGeometry, typename Strategy>
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static inline void apply(Geometry const& geometry,
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OutputGeometry& out,
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Strategy const& strategy)
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{
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BOOST_CONCEPT_ASSERT( (geometry::concepts::ConvexHullStrategy<Strategy>) );
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dispatch::convex_hull<Geometry>::apply(geometry, out, strategy);
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}
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template <typename Geometry, typename OutputGeometry>
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static inline void apply(Geometry const& geometry,
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OutputGeometry& out,
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default_strategy)
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{
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typedef typename strategy_convex_hull<
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Geometry,
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typename point_type<Geometry>::type
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>::type strategy_type;
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apply(geometry, out, strategy_type());
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}
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};
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struct convex_hull_insert
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{
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template <typename Geometry, typename OutputIterator, typename Strategy>
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static inline OutputIterator apply(Geometry const& geometry,
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OutputIterator& out,
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Strategy const& strategy)
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{
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BOOST_CONCEPT_ASSERT( (geometry::concepts::ConvexHullStrategy<Strategy>) );
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return dispatch::convex_hull_insert<
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geometry::point_order<Geometry>::value,
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geometry::closure<Geometry>::value
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>::apply(geometry, out, strategy);
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}
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template <typename Geometry, typename OutputIterator>
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static inline OutputIterator apply(Geometry const& geometry,
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OutputIterator& out,
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default_strategy)
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{
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typedef typename strategy_convex_hull<
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Geometry,
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typename point_type<Geometry>::type
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>::type strategy_type;
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return apply(geometry, out, strategy_type());
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}
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};
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} // namespace resolve_strategy
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namespace resolve_variant {
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template <typename Geometry>
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struct convex_hull
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{
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template <typename OutputGeometry, typename Strategy>
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static inline void apply(Geometry const& geometry, OutputGeometry& out, Strategy const& strategy)
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{
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concepts::check_concepts_and_equal_dimensions<
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const Geometry,
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OutputGeometry
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>();
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resolve_strategy::convex_hull::apply(geometry, out, strategy);
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}
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};
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template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
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struct convex_hull<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
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{
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template <typename OutputGeometry, typename Strategy>
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struct visitor: boost::static_visitor<void>
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{
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OutputGeometry& m_out;
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Strategy const& m_strategy;
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visitor(OutputGeometry& out, Strategy const& strategy)
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: m_out(out), m_strategy(strategy)
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{}
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template <typename Geometry>
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void operator()(Geometry const& geometry) const
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{
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convex_hull<Geometry>::apply(geometry, m_out, m_strategy);
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}
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};
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template <typename OutputGeometry, typename Strategy>
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static inline void
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apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry,
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OutputGeometry& out,
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Strategy const& strategy)
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{
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boost::apply_visitor(visitor<OutputGeometry, Strategy>(out, strategy), geometry);
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}
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};
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template <typename Geometry>
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struct convex_hull_insert
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{
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template <typename OutputIterator, typename Strategy>
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static inline OutputIterator apply(Geometry const& geometry, OutputIterator& out, Strategy const& strategy)
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{
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// Concept: output point type = point type of input geometry
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concepts::check<Geometry const>();
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concepts::check<typename point_type<Geometry>::type>();
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return resolve_strategy::convex_hull_insert::apply(geometry, out, strategy);
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}
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};
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template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
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struct convex_hull_insert<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
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{
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template <typename OutputIterator, typename Strategy>
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struct visitor: boost::static_visitor<OutputIterator>
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{
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OutputIterator& m_out;
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Strategy const& m_strategy;
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visitor(OutputIterator& out, Strategy const& strategy)
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: m_out(out), m_strategy(strategy)
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{}
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template <typename Geometry>
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OutputIterator operator()(Geometry const& geometry) const
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{
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return convex_hull_insert<Geometry>::apply(geometry, m_out, m_strategy);
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}
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};
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template <typename OutputIterator, typename Strategy>
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static inline OutputIterator
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apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry,
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OutputIterator& out,
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Strategy const& strategy)
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{
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return boost::apply_visitor(visitor<OutputIterator, Strategy>(out, strategy), geometry);
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}
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};
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} // namespace resolve_variant
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template<typename Geometry, typename OutputGeometry, typename Strategy>
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inline void convex_hull(Geometry const& geometry,
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OutputGeometry& out, Strategy const& strategy)
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{
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if (geometry::is_empty(geometry))
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{
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// Leave output empty
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return;
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}
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resolve_variant::convex_hull<Geometry>::apply(geometry, out, strategy);
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}
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/*!
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\brief \brief_calc{convex hull}
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\ingroup convex_hull
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\details \details_calc{convex_hull,convex hull}.
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\tparam Geometry the input geometry type
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\tparam OutputGeometry the output geometry type
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\param geometry \param_geometry, input geometry
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\param hull \param_geometry \param_set{convex hull}
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\qbk{[include reference/algorithms/convex_hull.qbk]}
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*/
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template<typename Geometry, typename OutputGeometry>
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inline void convex_hull(Geometry const& geometry,
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OutputGeometry& hull)
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{
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geometry::convex_hull(geometry, hull, default_strategy());
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}
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#ifndef DOXYGEN_NO_DETAIL
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namespace detail { namespace convex_hull
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{
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template<typename Geometry, typename OutputIterator, typename Strategy>
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inline OutputIterator convex_hull_insert(Geometry const& geometry,
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OutputIterator out, Strategy const& strategy)
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{
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return resolve_variant::convex_hull_insert<Geometry>
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::apply(geometry, out, strategy);
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}
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/*!
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\brief Calculate the convex hull of a geometry, output-iterator version
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\ingroup convex_hull
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\tparam Geometry the input geometry type
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\tparam OutputIterator: an output-iterator
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\param geometry the geometry to calculate convex hull from
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\param out an output iterator outputing points of the convex hull
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\note This overloaded version outputs to an output iterator.
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In this case, nothing is known about its point-type or
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about its clockwise order. Therefore, the input point-type
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and order are copied
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*/
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template<typename Geometry, typename OutputIterator>
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inline OutputIterator convex_hull_insert(Geometry const& geometry,
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OutputIterator out)
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{
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return convex_hull_insert(geometry, out, default_strategy());
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}
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}} // namespace detail::convex_hull
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#endif // DOXYGEN_NO_DETAIL
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ALGORITHMS_CONVEX_HULL_HPP
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