132 lines
3.3 KiB
C++
132 lines
3.3 KiB
C++
/*****************************************************************************
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*
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* This file is part of Mapnik (c++ mapping toolkit)
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*
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* Copyright (C) 2015 Artem Pavlenko
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*
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*****************************************************************************/
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#ifndef MAPNIK_GEOMETRY_CENTROID_HPP
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#define MAPNIK_GEOMETRY_CENTROID_HPP
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#include <mapnik/geometry.hpp>
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#include <mapnik/geometry_adapters.hpp>
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#include <boost/geometry/algorithms/centroid.hpp>
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#include <mapnik/geometry_is_empty.hpp>
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#include <mapnik/geometry_remove_empty.hpp>
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namespace mapnik { namespace geometry {
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namespace detail {
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template <typename T>
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struct geometry_centroid
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{
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using result_type = bool;
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geometry_centroid(point<T> & pt)
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: pt_(pt) {}
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template <typename T1>
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result_type operator() (T1 const& geom) const
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{
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return util::apply_visitor(*this, geom);
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}
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result_type operator() (geometry_empty const&) const
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{
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return false;
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}
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result_type operator() (geometry_collection<T> const&) const
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{
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return false;
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}
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result_type operator() (point<T> const& geom) const
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{
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return centroid_simple(geom);
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}
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result_type operator() (line_string<T> const& geom) const
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{
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return centroid_simple(geom);
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}
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result_type operator() (polygon<T> const& geom) const
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{
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return centroid_simple(geom);
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}
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result_type operator() (multi_point<T> const& geom) const
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{
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return centroid_simple(geom);
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}
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result_type operator() (multi_line_string<T> const& geom) const
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{
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return centroid_multi(geom);
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}
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result_type operator() (multi_polygon<T> const& geom) const
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{
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return centroid_multi(geom);
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}
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point<T> & pt_;
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private:
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template <typename Geom>
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result_type centroid_simple(Geom const & geom) const
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{
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try
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{
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boost::geometry::centroid(geom, pt_);
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return true;
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}
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catch (boost::geometry::centroid_exception const & e)
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{
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return false;
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}
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}
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template <typename Geom>
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result_type centroid_multi(Geom const & geom) const
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{
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// https://github.com/mapnik/mapnik/issues/3169
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#if BOOST_VERSION <= 105900
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if (mapnik::geometry::has_empty(geom))
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{
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Geom stripped = mapnik::geometry::remove_empty(geom);
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return centroid_simple(stripped);
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}
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#endif
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return centroid_simple(geom);
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}
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};
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}
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template <typename T1, typename T2>
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inline bool centroid(T1 const& geom, point<T2> & pt)
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{
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return detail::geometry_centroid<T2>(pt)(geom);
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}
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}}
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#endif // MAPNIK_GEOMETRY_CENTROID_HPP
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