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178 lines
4.2 KiB
178 lines
4.2 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_MULTI_ALGORITHMS_CENTROID_HPP |
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#define BOOST_GEOMETRY_MULTI_ALGORITHMS_CENTROID_HPP |
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#include <boost/range.hpp> |
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#include <boost/geometry/algorithms/centroid.hpp> |
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#include <boost/geometry/algorithms/num_points.hpp> |
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#include <boost/geometry/multi/core/point_type.hpp> |
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#include <boost/geometry/multi/algorithms/detail/multi_sum.hpp> |
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#include <boost/geometry/multi/algorithms/num_points.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 centroid |
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{ |
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/*! |
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\brief Building block of a multi-point, to be used as Policy in the |
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more generec centroid_multi |
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*/ |
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template |
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< |
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typename Point, |
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typename Strategy |
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> |
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struct centroid_multi_point_state |
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{ |
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static inline void apply(Point const& point, |
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Strategy const& strategy, typename Strategy::state_type& state) |
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{ |
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strategy.apply(point, state); |
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} |
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}; |
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/*! |
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\brief Generic implementation which calls a policy to calculate the |
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centroid of the total of its single-geometries |
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\details The Policy is, in general, the single-version, with state. So |
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detail::centroid::centroid_polygon_state is used as a policy for this |
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detail::centroid::centroid_multi |
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*/ |
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template |
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< |
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typename Multi, |
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typename Point, |
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typename Strategy, |
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typename Policy |
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> |
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struct centroid_multi |
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{ |
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static inline void apply(Multi const& multi, Point& centroid, |
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Strategy const& strategy) |
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{ |
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// If there is nothing in any of the ranges, it is not possible |
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// to calculate the centroid |
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if (geometry::num_points(multi) == 0) |
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{ |
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throw centroid_exception(); |
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} |
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typename Strategy::state_type state; |
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for (typename boost::range_iterator<Multi const>::type |
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it = boost::begin(multi); |
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it != boost::end(multi); |
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++it) |
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{ |
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Policy::apply(*it, strategy, state); |
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} |
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Strategy::result(state, centroid); |
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} |
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}; |
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}} // namespace detail::centroid |
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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 MultiLinestring, |
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typename Point, |
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typename Strategy |
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> |
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struct centroid<multi_linestring_tag, MultiLinestring, Point, Strategy> |
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: detail::centroid::centroid_multi |
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< |
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MultiLinestring, |
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Point, |
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Strategy, |
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detail::centroid::centroid_range_state |
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< |
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typename boost::range_value<MultiLinestring>::type, |
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closed, |
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Strategy |
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> |
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> |
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{}; |
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template |
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< |
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typename MultiPolygon, |
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typename Point, |
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typename Strategy |
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> |
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struct centroid<multi_polygon_tag, MultiPolygon, Point, Strategy> |
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: detail::centroid::centroid_multi |
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< |
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MultiPolygon, |
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Point, |
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Strategy, |
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detail::centroid::centroid_polygon_state |
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< |
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typename boost::range_value<MultiPolygon>::type, |
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Strategy |
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> |
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> |
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{}; |
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template |
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< |
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typename MultiPoint, |
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typename Point, |
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typename Strategy |
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> |
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struct centroid<multi_point_tag, MultiPoint, Point, Strategy> |
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: detail::centroid::centroid_multi |
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< |
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MultiPoint, |
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Point, |
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Strategy, |
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detail::centroid::centroid_multi_point_state |
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< |
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typename boost::range_value<MultiPoint>::type, |
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Strategy |
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> |
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> |
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{}; |
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} // namespace dispatch |
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#endif |
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}} // namespace boost::geometry |
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#endif // BOOST_GEOMETRY_MULTI_ALGORITHMS_CENTROID_HPP |
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