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405 lines
12 KiB
405 lines
12 KiB
// Boost.Geometry (aka GGL, Generic Geometry Library) |
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// Copyright (c) 2007-2011 Barend Gehrels, Amsterdam, the Netherlands. |
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// Copyright (c) 2008-2011 Bruno Lalande, Paris, France. |
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// Copyright (c) 2009-2011 Mateusz Loskot, London, UK. |
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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_SIMPLIFY_HPP |
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#define BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP |
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#include <cstddef> |
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#include <boost/range.hpp> |
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#include <boost/typeof/typeof.hpp> |
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#include <boost/geometry/core/cs.hpp> |
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#include <boost/geometry/core/closure.hpp> |
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#include <boost/geometry/core/ring_type.hpp> |
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#include <boost/geometry/core/exterior_ring.hpp> |
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#include <boost/geometry/core/interior_rings.hpp> |
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#include <boost/geometry/core/mutable_range.hpp> |
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#include <boost/geometry/geometries/concepts/check.hpp> |
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#include <boost/geometry/strategies/agnostic/simplify_douglas_peucker.hpp> |
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#include <boost/geometry/strategies/concepts/simplify_concept.hpp> |
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#include <boost/geometry/algorithms/clear.hpp> |
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#include <boost/geometry/algorithms/convert.hpp> |
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#include <boost/geometry/algorithms/num_interior_rings.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 simplify |
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{ |
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template<typename Range, typename Strategy> |
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struct simplify_range_insert |
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{ |
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template <typename OutputIterator, typename Distance> |
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static inline void apply(Range const& range, OutputIterator out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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if (boost::size(range) <= 2 || max_distance < 0) |
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{ |
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std::copy(boost::begin(range), boost::end(range), out); |
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} |
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else |
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{ |
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strategy.apply(range, out, max_distance); |
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} |
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} |
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}; |
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template<typename Range, typename Strategy> |
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struct simplify_copy |
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{ |
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template <typename Distance> |
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static inline void apply(Range const& range, Range& out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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std::copy |
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( |
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boost::begin(range), boost::end(range), std::back_inserter(out) |
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); |
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} |
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}; |
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template<typename Range, typename Strategy, std::size_t Minimum> |
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struct simplify_range |
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{ |
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template <typename Distance> |
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static inline void apply(Range const& range, Range& out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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// Call do_container for a linestring / ring |
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/* For a RING: |
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The first/last point (the closing point of the ring) should maybe |
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be excluded because it lies on a line with second/one but last. |
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Here it is never excluded. |
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Note also that, especially if max_distance is too large, |
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the output ring might be self intersecting while the input ring is |
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not, although chances are low in normal polygons |
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Finally the inputring might have 3 (open) or 4 (closed) points (=correct), |
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the output < 3 or 4(=wrong) |
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*/ |
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if (boost::size(range) <= int(Minimum) || max_distance < 0.0) |
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{ |
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simplify_copy<Range, Strategy>::apply |
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( |
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range, out, max_distance, strategy |
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); |
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} |
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else |
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{ |
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simplify_range_insert<Range, Strategy>::apply |
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( |
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range, std::back_inserter(out), max_distance, strategy |
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); |
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} |
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} |
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}; |
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template<typename Polygon, typename Strategy> |
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struct simplify_polygon |
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{ |
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template <typename Distance> |
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static inline void apply(Polygon const& poly_in, Polygon& poly_out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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typedef typename ring_type<Polygon>::type ring_type; |
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int const Minimum = core_detail::closure::minimum_ring_size |
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< |
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geometry::closure<Polygon>::value |
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>::value; |
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// Note that if there are inner rings, and distance is too large, |
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// they might intersect with the outer ring in the output, |
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// while it didn't in the input. |
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simplify_range<ring_type, Strategy, Minimum>::apply(exterior_ring(poly_in), |
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exterior_ring(poly_out), |
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max_distance, strategy); |
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traits::resize |
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< |
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typename boost::remove_reference |
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< |
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typename traits::interior_mutable_type<Polygon>::type |
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>::type |
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>::apply(interior_rings(poly_out), num_interior_rings(poly_in)); |
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typename interior_return_type<Polygon const>::type rings_in |
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= interior_rings(poly_in); |
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typename interior_return_type<Polygon>::type rings_out |
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= interior_rings(poly_out); |
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BOOST_AUTO_TPL(it_out, boost::begin(rings_out)); |
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for (BOOST_AUTO_TPL(it_in, boost::begin(rings_in)); |
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it_in != boost::end(rings_in); |
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++it_in, ++it_out) |
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{ |
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simplify_range<ring_type, Strategy, Minimum>::apply(*it_in, |
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*it_out, max_distance, strategy); |
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} |
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} |
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}; |
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}} // namespace detail::simplify |
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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 <typename Tag, typename Geometry, typename Strategy> |
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struct simplify |
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{ |
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}; |
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template <typename Point, typename Strategy> |
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struct simplify<point_tag, Point, Strategy> |
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{ |
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template <typename Distance> |
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static inline void apply(Point const& point, Point& out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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geometry::convert(point, out); |
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} |
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}; |
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template <typename Linestring, typename Strategy> |
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struct simplify<linestring_tag, Linestring, Strategy> |
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: detail::simplify::simplify_range |
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< |
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Linestring, |
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Strategy, |
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2 |
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> |
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{}; |
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template <typename Ring, typename Strategy> |
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struct simplify<ring_tag, Ring, Strategy> |
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: detail::simplify::simplify_range |
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< |
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Ring, |
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Strategy, |
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core_detail::closure::minimum_ring_size |
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< |
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geometry::closure<Ring>::value |
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>::value |
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> |
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{}; |
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template <typename Polygon, typename Strategy> |
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struct simplify<polygon_tag, Polygon, Strategy> |
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: detail::simplify::simplify_polygon |
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< |
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Polygon, |
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Strategy |
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> |
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{}; |
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template <typename Tag, typename Geometry, typename Strategy> |
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struct simplify_insert |
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{ |
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}; |
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template <typename Linestring, typename Strategy> |
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struct simplify_insert<linestring_tag, Linestring, Strategy> |
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: detail::simplify::simplify_range_insert |
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< |
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Linestring, |
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Strategy |
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> |
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{}; |
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template <typename Ring, typename Strategy> |
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struct simplify_insert<ring_tag, Ring, Strategy> |
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: detail::simplify::simplify_range_insert |
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< |
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Ring, |
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Strategy |
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> |
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{}; |
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} // namespace dispatch |
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#endif // DOXYGEN_NO_DISPATCH |
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/*! |
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\brief Simplify a geometry using a specified strategy |
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\ingroup simplify |
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\tparam Geometry \tparam_geometry |
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\tparam Distance A numerical distance measure |
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\tparam Strategy A type fulfilling a SimplifyStrategy concept |
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\param strategy A strategy to calculate simplification |
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\param geometry input geometry, to be simplified |
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\param out output geometry, simplified version of the input geometry |
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\param max_distance distance (in units of input coordinates) of a vertex |
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to other segments to be removed |
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\param strategy simplify strategy to be used for simplification, might |
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include point-distance strategy |
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\image html svg_simplify_country.png "The image below presents the simplified country" |
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\qbk{distinguish,with strategy} |
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*/ |
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template<typename Geometry, typename Distance, typename Strategy> |
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inline void simplify(Geometry const& geometry, Geometry& out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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concept::check<Geometry>(); |
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BOOST_CONCEPT_ASSERT( (geometry::concept::SimplifyStrategy<Strategy>) ); |
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geometry::clear(out); |
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dispatch::simplify |
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< |
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typename tag<Geometry>::type, |
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Geometry, |
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Strategy |
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>::apply(geometry, out, max_distance, strategy); |
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} |
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/*! |
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\brief Simplify a geometry |
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\ingroup simplify |
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\tparam Geometry \tparam_geometry |
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\tparam Distance \tparam_numeric |
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\note This version of simplify simplifies a geometry using the default |
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strategy (Douglas Peucker), |
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\param geometry input geometry, to be simplified |
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\param out output geometry, simplified version of the input geometry |
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\param max_distance distance (in units of input coordinates) of a vertex |
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to other segments to be removed |
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\qbk{[include reference/algorithms/simplify.qbk]} |
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*/ |
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template<typename Geometry, typename Distance> |
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inline void simplify(Geometry const& geometry, Geometry& out, |
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Distance const& max_distance) |
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{ |
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concept::check<Geometry>(); |
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typedef typename point_type<Geometry>::type point_type; |
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typedef typename strategy::distance::services::default_strategy |
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< |
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segment_tag, point_type |
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>::type ds_strategy_type; |
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typedef strategy::simplify::douglas_peucker |
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< |
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point_type, ds_strategy_type |
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> strategy_type; |
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simplify(geometry, out, max_distance, strategy_type()); |
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} |
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#ifndef DOXYGEN_NO_DETAIL |
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namespace detail { namespace simplify |
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{ |
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/*! |
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\brief Simplify a geometry, using an output iterator |
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and a specified strategy |
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\ingroup simplify |
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\tparam Geometry \tparam_geometry |
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\param geometry input geometry, to be simplified |
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\param out output iterator, outputs all simplified points |
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\param max_distance distance (in units of input coordinates) of a vertex |
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to other segments to be removed |
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\param strategy simplify strategy to be used for simplification, |
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might include point-distance strategy |
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\qbk{distinguish,with strategy} |
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\qbk{[include reference/algorithms/simplify.qbk]} |
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*/ |
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template<typename Geometry, typename OutputIterator, typename Distance, typename Strategy> |
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inline void simplify_insert(Geometry const& geometry, OutputIterator out, |
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Distance const& max_distance, Strategy const& strategy) |
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{ |
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concept::check<Geometry const>(); |
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BOOST_CONCEPT_ASSERT( (geometry::concept::SimplifyStrategy<Strategy>) ); |
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dispatch::simplify_insert |
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< |
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typename tag<Geometry>::type, |
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Geometry, |
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Strategy |
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>::apply(geometry, out, max_distance, strategy); |
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} |
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/*! |
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\brief Simplify a geometry, using an output iterator |
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\ingroup simplify |
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\tparam Geometry \tparam_geometry |
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\param geometry input geometry, to be simplified |
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\param out output iterator, outputs all simplified points |
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\param max_distance distance (in units of input coordinates) of a vertex |
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to other segments to be removed |
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\qbk{[include reference/algorithms/simplify_insert.qbk]} |
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*/ |
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template<typename Geometry, typename OutputIterator, typename Distance> |
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inline void simplify_insert(Geometry const& geometry, OutputIterator out, |
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Distance const& max_distance) |
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{ |
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typedef typename point_type<Geometry>::type point_type; |
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// Concept: output point type = point type of input geometry |
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concept::check<Geometry const>(); |
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concept::check<point_type>(); |
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typedef typename strategy::distance::services::default_strategy |
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< |
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segment_tag, point_type |
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>::type ds_strategy_type; |
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typedef strategy::simplify::douglas_peucker |
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< |
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point_type, ds_strategy_type |
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> strategy_type; |
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dispatch::simplify_insert |
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< |
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typename tag<Geometry>::type, |
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Geometry, |
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strategy_type |
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>::apply(geometry, out, max_distance, strategy_type()); |
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} |
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}} // namespace detail::simplify |
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#endif // DOXYGEN_NO_DETAIL |
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}} // namespace boost::geometry |
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#endif // BOOST_GEOMETRY_ALGORITHMS_SIMPLIFY_HPP
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