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- // Boost.Geometry (aka GGL, Generic Geometry Library)
- // Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands.
- // Copyright (c) 2008-2015 Bruno Lalande, Paris, France.
- // Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
- // 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_ALGORITHMS_SIMPLIFY_HPP
- #define BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP
- #include <cstddef>
- #include <boost/core/ignore_unused.hpp>
- #include <boost/range.hpp>
- #include <boost/variant/apply_visitor.hpp>
- #include <boost/variant/static_visitor.hpp>
- #include <boost/variant/variant_fwd.hpp>
- #include <boost/geometry/core/cs.hpp>
- #include <boost/geometry/core/closure.hpp>
- #include <boost/geometry/core/exterior_ring.hpp>
- #include <boost/geometry/core/interior_rings.hpp>
- #include <boost/geometry/core/mutable_range.hpp>
- #include <boost/geometry/core/tags.hpp>
- #include <boost/geometry/geometries/concepts/check.hpp>
- #include <boost/geometry/strategies/agnostic/simplify_douglas_peucker.hpp>
- #include <boost/geometry/strategies/concepts/simplify_concept.hpp>
- #include <boost/geometry/strategies/default_strategy.hpp>
- #include <boost/geometry/strategies/distance.hpp>
- #include <boost/geometry/algorithms/clear.hpp>
- #include <boost/geometry/algorithms/convert.hpp>
- #include <boost/geometry/algorithms/not_implemented.hpp>
- #include <boost/geometry/algorithms/detail/distance/default_strategies.hpp>
- namespace boost { namespace geometry
- {
- #ifndef DOXYGEN_NO_DETAIL
- namespace detail { namespace simplify
- {
- struct simplify_range_insert
- {
- template<typename Range, typename Strategy, typename OutputIterator, typename Distance>
- static inline void apply(Range const& range, OutputIterator out,
- Distance const& max_distance, Strategy const& strategy)
- {
- boost::ignore_unused(strategy);
- if (boost::size(range) <= 2 || max_distance < 0)
- {
- std::copy(boost::begin(range), boost::end(range), out);
- }
- else
- {
- strategy.apply(range, out, max_distance);
- }
- }
- };
- struct simplify_copy
- {
- template <typename Range, typename Strategy, typename Distance>
- static inline void apply(Range const& range, Range& out,
- Distance const& , Strategy const& )
- {
- std::copy
- (
- boost::begin(range), boost::end(range), geometry::range::back_inserter(out)
- );
- }
- };
- template<std::size_t Minimum>
- struct simplify_range
- {
- template <typename Range, typename Strategy, typename Distance>
- static inline void apply(Range const& range, Range& out,
- Distance const& max_distance, Strategy const& strategy)
- {
- // Call do_container for a linestring / ring
- /* For a RING:
- The first/last point (the closing point of the ring) should maybe
- be excluded because it lies on a line with second/one but last.
- Here it is never excluded.
- Note also that, especially if max_distance is too large,
- the output ring might be self intersecting while the input ring is
- not, although chances are low in normal polygons
- Finally the inputring might have 3 (open) or 4 (closed) points (=correct),
- the output < 3 or 4(=wrong)
- */
- if (boost::size(range) <= int(Minimum) || max_distance < 0.0)
- {
- simplify_copy::apply(range, out, max_distance, strategy);
- }
- else
- {
- simplify_range_insert::apply
- (
- range, geometry::range::back_inserter(out), max_distance, strategy
- );
- }
- }
- };
- struct simplify_polygon
- {
- private:
- template
- <
- std::size_t Minimum,
- typename IteratorIn,
- typename IteratorOut,
- typename Distance,
- typename Strategy
- >
- static inline void iterate(IteratorIn begin, IteratorIn end,
- IteratorOut it_out,
- Distance const& max_distance, Strategy const& strategy)
- {
- for (IteratorIn it_in = begin; it_in != end; ++it_in, ++it_out)
- {
- simplify_range<Minimum>::apply(*it_in, *it_out, max_distance, strategy);
- }
- }
- template
- <
- std::size_t Minimum,
- typename InteriorRingsIn,
- typename InteriorRingsOut,
- typename Distance,
- typename Strategy
- >
- static inline void apply_interior_rings(
- InteriorRingsIn const& interior_rings_in,
- InteriorRingsOut& interior_rings_out,
- Distance const& max_distance, Strategy const& strategy)
- {
- traits::resize<InteriorRingsOut>::apply(interior_rings_out,
- boost::size(interior_rings_in));
- iterate<Minimum>(
- boost::begin(interior_rings_in), boost::end(interior_rings_in),
- boost::begin(interior_rings_out),
- max_distance, strategy);
- }
- public:
- template <typename Polygon, typename Strategy, typename Distance>
- static inline void apply(Polygon const& poly_in, Polygon& poly_out,
- Distance const& max_distance, Strategy const& strategy)
- {
- std::size_t const minimum = core_detail::closure::minimum_ring_size
- <
- geometry::closure<Polygon>::value
- >::value;
- // Note that if there are inner rings, and distance is too large,
- // they might intersect with the outer ring in the output,
- // while it didn't in the input.
- simplify_range<minimum>::apply(exterior_ring(poly_in),
- exterior_ring(poly_out),
- max_distance, strategy);
- apply_interior_rings<minimum>(interior_rings(poly_in),
- interior_rings(poly_out),
- max_distance, strategy);
- }
- };
- template<typename Policy>
- struct simplify_multi
- {
- template <typename MultiGeometry, typename Strategy, typename Distance>
- static inline void apply(MultiGeometry const& multi, MultiGeometry& out,
- Distance const& max_distance, Strategy const& strategy)
- {
- traits::resize<MultiGeometry>::apply(out, boost::size(multi));
- typename boost::range_iterator<MultiGeometry>::type it_out
- = boost::begin(out);
- for (typename boost::range_iterator<MultiGeometry const>::type
- it_in = boost::begin(multi);
- it_in != boost::end(multi);
- ++it_in, ++it_out)
- {
- Policy::apply(*it_in, *it_out, max_distance, strategy);
- }
- }
- };
- }} // namespace detail::simplify
- #endif // DOXYGEN_NO_DETAIL
- #ifndef DOXYGEN_NO_DISPATCH
- namespace dispatch
- {
- template
- <
- typename Geometry,
- typename Tag = typename tag<Geometry>::type
- >
- struct simplify: not_implemented<Tag>
- {};
- template <typename Point>
- struct simplify<Point, point_tag>
- {
- template <typename Distance, typename Strategy>
- static inline void apply(Point const& point, Point& out,
- Distance const& , Strategy const& )
- {
- geometry::convert(point, out);
- }
- };
- template <typename Linestring>
- struct simplify<Linestring, linestring_tag>
- : detail::simplify::simplify_range<2>
- {};
- template <typename Ring>
- struct simplify<Ring, ring_tag>
- : detail::simplify::simplify_range
- <
- core_detail::closure::minimum_ring_size
- <
- geometry::closure<Ring>::value
- >::value
- >
- {};
- template <typename Polygon>
- struct simplify<Polygon, polygon_tag>
- : detail::simplify::simplify_polygon
- {};
- template
- <
- typename Geometry,
- typename Tag = typename tag<Geometry>::type
- >
- struct simplify_insert: not_implemented<Tag>
- {};
- template <typename Linestring>
- struct simplify_insert<Linestring, linestring_tag>
- : detail::simplify::simplify_range_insert
- {};
- template <typename Ring>
- struct simplify_insert<Ring, ring_tag>
- : detail::simplify::simplify_range_insert
- {};
- template <typename MultiPoint>
- struct simplify<MultiPoint, multi_point_tag>
- : detail::simplify::simplify_copy
- {};
- template <typename MultiLinestring>
- struct simplify<MultiLinestring, multi_linestring_tag>
- : detail::simplify::simplify_multi<detail::simplify::simplify_range<2> >
- {};
- template <typename MultiPolygon>
- struct simplify<MultiPolygon, multi_polygon_tag>
- : detail::simplify::simplify_multi<detail::simplify::simplify_polygon>
- {};
- } // namespace dispatch
- #endif // DOXYGEN_NO_DISPATCH
- namespace resolve_strategy
- {
- struct simplify
- {
- template <typename Geometry, typename Distance, typename Strategy>
- static inline void apply(Geometry const& geometry,
- Geometry& out,
- Distance const& max_distance,
- Strategy const& strategy)
- {
- dispatch::simplify<Geometry>::apply(geometry, out, max_distance, strategy);
- }
- template <typename Geometry, typename Distance>
- static inline void apply(Geometry const& geometry,
- Geometry& out,
- Distance const& max_distance,
- default_strategy)
- {
- typedef typename point_type<Geometry>::type point_type;
- typedef typename strategy::distance::services::default_strategy
- <
- point_tag, segment_tag, point_type
- >::type ds_strategy_type;
- typedef strategy::simplify::douglas_peucker
- <
- point_type, ds_strategy_type
- > strategy_type;
- BOOST_CONCEPT_ASSERT(
- (concept::SimplifyStrategy<strategy_type, point_type>)
- );
- apply(geometry, out, max_distance, strategy_type());
- }
- };
- struct simplify_insert
- {
- template
- <
- typename Geometry,
- typename OutputIterator,
- typename Distance,
- typename Strategy
- >
- static inline void apply(Geometry const& geometry,
- OutputIterator& out,
- Distance const& max_distance,
- Strategy const& strategy)
- {
- dispatch::simplify_insert<Geometry>::apply(geometry, out, max_distance, strategy);
- }
- template <typename Geometry, typename OutputIterator, typename Distance>
- static inline void apply(Geometry const& geometry,
- OutputIterator& out,
- Distance const& max_distance,
- default_strategy)
- {
- typedef typename point_type<Geometry>::type point_type;
- typedef typename strategy::distance::services::default_strategy
- <
- point_tag, segment_tag, point_type
- >::type ds_strategy_type;
- typedef strategy::simplify::douglas_peucker
- <
- point_type, ds_strategy_type
- > strategy_type;
- BOOST_CONCEPT_ASSERT(
- (concept::SimplifyStrategy<strategy_type, point_type>)
- );
- apply(geometry, out, max_distance, strategy_type());
- }
- };
- } // namespace resolve_strategy
- namespace resolve_variant {
- template <typename Geometry>
- struct simplify
- {
- template <typename Distance, typename Strategy>
- static inline void apply(Geometry const& geometry,
- Geometry& out,
- Distance const& max_distance,
- Strategy const& strategy)
- {
- resolve_strategy::simplify::apply(geometry, out, max_distance, strategy);
- }
- };
- template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
- struct simplify<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
- {
- template <typename Distance, typename Strategy>
- struct visitor: boost::static_visitor<void>
- {
- Distance const& m_max_distance;
- Strategy const& m_strategy;
- visitor(Distance const& max_distance, Strategy const& strategy)
- : m_max_distance(max_distance)
- , m_strategy(strategy)
- {}
- template <typename Geometry>
- void operator()(Geometry const& geometry, Geometry& out) const
- {
- simplify<Geometry>::apply(geometry, out, m_max_distance, m_strategy);
- }
- };
- template <typename Distance, typename Strategy>
- static inline void
- apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry,
- boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>& out,
- Distance const& max_distance,
- Strategy const& strategy)
- {
- boost::apply_visitor(
- visitor<Distance, Strategy>(max_distance, strategy),
- geometry,
- out
- );
- }
- };
- } // namespace resolve_variant
- /*!
- \brief Simplify a geometry using a specified strategy
- \ingroup simplify
- \tparam Geometry \tparam_geometry
- \tparam Distance A numerical distance measure
- \tparam Strategy A type fulfilling a SimplifyStrategy concept
- \param strategy A strategy to calculate simplification
- \param geometry input geometry, to be simplified
- \param out output geometry, simplified version of the input geometry
- \param max_distance distance (in units of input coordinates) of a vertex
- to other segments to be removed
- \param strategy simplify strategy to be used for simplification, might
- include point-distance strategy
- \image html svg_simplify_country.png "The image below presents the simplified country"
- \qbk{distinguish,with strategy}
- */
- template<typename Geometry, typename Distance, typename Strategy>
- inline void simplify(Geometry const& geometry, Geometry& out,
- Distance const& max_distance, Strategy const& strategy)
- {
- concept::check<Geometry>();
- geometry::clear(out);
- resolve_variant::simplify<Geometry>::apply(geometry, out, max_distance, strategy);
- }
- /*!
- \brief Simplify a geometry
- \ingroup simplify
- \tparam Geometry \tparam_geometry
- \tparam Distance \tparam_numeric
- \note This version of simplify simplifies a geometry using the default
- strategy (Douglas Peucker),
- \param geometry input geometry, to be simplified
- \param out output geometry, simplified version of the input geometry
- \param max_distance distance (in units of input coordinates) of a vertex
- to other segments to be removed
- \qbk{[include reference/algorithms/simplify.qbk]}
- */
- template<typename Geometry, typename Distance>
- inline void simplify(Geometry const& geometry, Geometry& out,
- Distance const& max_distance)
- {
- concept::check<Geometry>();
- geometry::simplify(geometry, out, max_distance, default_strategy());
- }
- #ifndef DOXYGEN_NO_DETAIL
- namespace detail { namespace simplify
- {
- /*!
- \brief Simplify a geometry, using an output iterator
- and a specified strategy
- \ingroup simplify
- \tparam Geometry \tparam_geometry
- \param geometry input geometry, to be simplified
- \param out output iterator, outputs all simplified points
- \param max_distance distance (in units of input coordinates) of a vertex
- to other segments to be removed
- \param strategy simplify strategy to be used for simplification,
- might include point-distance strategy
- \qbk{distinguish,with strategy}
- \qbk{[include reference/algorithms/simplify.qbk]}
- */
- template<typename Geometry, typename OutputIterator, typename Distance, typename Strategy>
- inline void simplify_insert(Geometry const& geometry, OutputIterator out,
- Distance const& max_distance, Strategy const& strategy)
- {
- concept::check<Geometry const>();
- resolve_strategy::simplify_insert::apply(geometry, out, max_distance, strategy);
- }
- /*!
- \brief Simplify a geometry, using an output iterator
- \ingroup simplify
- \tparam Geometry \tparam_geometry
- \param geometry input geometry, to be simplified
- \param out output iterator, outputs all simplified points
- \param max_distance distance (in units of input coordinates) of a vertex
- to other segments to be removed
- \qbk{[include reference/algorithms/simplify_insert.qbk]}
- */
- template<typename Geometry, typename OutputIterator, typename Distance>
- inline void simplify_insert(Geometry const& geometry, OutputIterator out,
- Distance const& max_distance)
- {
- // Concept: output point type = point type of input geometry
- concept::check<Geometry const>();
- concept::check<typename point_type<Geometry>::type>();
- simplify_insert(geometry, out, max_distance, default_strategy());
- }
- }} // namespace detail::simplify
- #endif // DOXYGEN_NO_DETAIL
- }} // namespace boost::geometry
- #endif // BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP
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