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- // Boost.Geometry
- // Copyright (c) 2017 Barend Gehrels, 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_CORRECT_CLOSURE_HPP
- #define BOOST_GEOMETRY_ALGORITHMS_CORRECT_CLOSURE_HPP
- #include <cstddef>
- #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/algorithms/detail/interior_iterator.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/ring_type.hpp>
- #include <boost/geometry/core/tags.hpp>
- #include <boost/geometry/geometries/concepts/check.hpp>
- #include <boost/geometry/algorithms/disjoint.hpp>
- #include <boost/geometry/algorithms/detail/multi_modify.hpp>
- namespace boost { namespace geometry
- {
- // Silence warning C4127: conditional expression is constant
- #if defined(_MSC_VER)
- #pragma warning(push)
- #pragma warning(disable : 4127)
- #endif
- #ifndef DOXYGEN_NO_DETAIL
- namespace detail { namespace correct_closure
- {
- template <typename Geometry>
- struct nop
- {
- static inline void apply(Geometry& )
- {}
- };
- // Close a ring, if not closed, or open it
- template <typename Ring>
- struct close_or_open_ring
- {
- static inline void apply(Ring& r)
- {
- if (boost::size(r) <= 2)
- {
- return;
- }
- bool const disjoint = geometry::disjoint(*boost::begin(r),
- *(boost::end(r) - 1));
- closure_selector const s = geometry::closure<Ring>::value;
- if (disjoint && s == closed)
- {
- // Close it by adding first point
- geometry::append(r, *boost::begin(r));
- }
- else if (! disjoint && s != closed)
- {
- // Open it by removing last point
- geometry::traits::resize<Ring>::apply(r, boost::size(r) - 1);
- }
- }
- };
- // Close/open exterior ring and all its interior rings
- template <typename Polygon>
- struct close_or_open_polygon
- {
- typedef typename ring_type<Polygon>::type ring_type;
- static inline void apply(Polygon& poly)
- {
- close_or_open_ring<ring_type>::apply(exterior_ring(poly));
- typename interior_return_type<Polygon>::type
- rings = interior_rings(poly);
- for (typename detail::interior_iterator<Polygon>::type
- it = boost::begin(rings); it != boost::end(rings); ++it)
- {
- close_or_open_ring<ring_type>::apply(*it);
- }
- }
- };
- }} // namespace detail::correct_closure
- #endif // DOXYGEN_NO_DETAIL
- #ifndef DOXYGEN_NO_DISPATCH
- namespace dispatch
- {
- template <typename Geometry, typename Tag = typename tag<Geometry>::type>
- struct correct_closure: not_implemented<Tag>
- {};
- template <typename Point>
- struct correct_closure<Point, point_tag>
- : detail::correct_closure::nop<Point>
- {};
- template <typename LineString>
- struct correct_closure<LineString, linestring_tag>
- : detail::correct_closure::nop<LineString>
- {};
- template <typename Segment>
- struct correct_closure<Segment, segment_tag>
- : detail::correct_closure::nop<Segment>
- {};
- template <typename Box>
- struct correct_closure<Box, box_tag>
- : detail::correct_closure::nop<Box>
- {};
- template <typename Ring>
- struct correct_closure<Ring, ring_tag>
- : detail::correct_closure::close_or_open_ring<Ring>
- {};
- template <typename Polygon>
- struct correct_closure<Polygon, polygon_tag>
- : detail::correct_closure::close_or_open_polygon<Polygon>
- {};
- template <typename MultiPoint>
- struct correct_closure<MultiPoint, multi_point_tag>
- : detail::correct_closure::nop<MultiPoint>
- {};
- template <typename MultiLineString>
- struct correct_closure<MultiLineString, multi_linestring_tag>
- : detail::correct_closure::nop<MultiLineString>
- {};
- template <typename Geometry>
- struct correct_closure<Geometry, multi_polygon_tag>
- : detail::multi_modify
- <
- Geometry,
- detail::correct_closure::close_or_open_polygon
- <
- typename boost::range_value<Geometry>::type
- >
- >
- {};
- } // namespace dispatch
- #endif // DOXYGEN_NO_DISPATCH
- namespace resolve_variant
- {
- template <typename Geometry>
- struct correct_closure
- {
- static inline void apply(Geometry& geometry)
- {
- concepts::check<Geometry const>();
- dispatch::correct_closure<Geometry>::apply(geometry);
- }
- };
- template <BOOST_VARIANT_ENUM_PARAMS(typename T)>
- struct correct_closure<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> >
- {
- struct visitor: boost::static_visitor<void>
- {
- template <typename Geometry>
- void operator()(Geometry& geometry) const
- {
- correct_closure<Geometry>::apply(geometry);
- }
- };
- static inline void
- apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)>& geometry)
- {
- visitor vis;
- boost::apply_visitor(vis, geometry);
- }
- };
- } // namespace resolve_variant
- /*!
- \brief Closes or opens a geometry, according to its type
- \details Corrects a geometry w.r.t. closure points to all rings which do not
- have a closing point and are typed as they should have one, the first point
- is appended.
- \ingroup correct_closure
- \tparam Geometry \tparam_geometry
- \param geometry \param_geometry which will be corrected if necessary
- */
- template <typename Geometry>
- inline void correct_closure(Geometry& geometry)
- {
- resolve_variant::correct_closure<Geometry>::apply(geometry);
- }
- #if defined(_MSC_VER)
- #pragma warning(pop)
- #endif
- }} // namespace boost::geometry
- #endif // BOOST_GEOMETRY_ALGORITHMS_CORRECT_CLOSURE_HPP
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