172 lines
5.1 KiB
C++
172 lines
5.1 KiB
C++
// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
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// Copyright (c) 2008-2012 Bruno Lalande, Paris, France.
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// Copyright (c) 2009-2012 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_BUFFER_HPP
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#define BOOST_GEOMETRY_ALGORITHMS_BUFFER_HPP
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#include <cstddef>
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#include <boost/numeric/conversion/cast.hpp>
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#include <boost/geometry/algorithms/clear.hpp>
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#include <boost/geometry/algorithms/not_implemented.hpp>
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#include <boost/geometry/algorithms/detail/disjoint.hpp>
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#include <boost/geometry/arithmetic/arithmetic.hpp>
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#include <boost/geometry/geometries/concepts/check.hpp>
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#include <boost/geometry/geometries/segment.hpp>
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#include <boost/geometry/util/math.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 buffer
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{
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template <typename BoxIn, typename BoxOut, typename T, std::size_t C, std::size_t D, std::size_t N>
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struct box_loop
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{
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typedef typename coordinate_type<BoxOut>::type coordinate_type;
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static inline void apply(BoxIn const& box_in, T const& distance, BoxOut& box_out)
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{
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coordinate_type d = distance;
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set<C, D>(box_out, get<C, D>(box_in) + d);
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box_loop<BoxIn, BoxOut, T, C, D + 1, N>::apply(box_in, distance, box_out);
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}
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};
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template <typename BoxIn, typename BoxOut, typename T, std::size_t C, std::size_t N>
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struct box_loop<BoxIn, BoxOut, T, C, N, N>
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{
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static inline void apply(BoxIn const&, T const&, BoxOut&) {}
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};
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// Extends a box with the same amount in all directions
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template<typename BoxIn, typename BoxOut, typename T>
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inline void buffer_box(BoxIn const& box_in, T const& distance, BoxOut& box_out)
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{
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assert_dimension_equal<BoxIn, BoxOut>();
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static const std::size_t N = dimension<BoxIn>::value;
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box_loop<BoxIn, BoxOut, T, min_corner, 0, N>::apply(box_in, -distance, box_out);
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box_loop<BoxIn, BoxOut, T, max_corner, 0, N>::apply(box_in, distance, box_out);
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}
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}} // namespace detail::buffer
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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 Input,
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typename Output,
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typename TagIn = typename tag<Input>::type,
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typename TagOut = typename tag<Output>::type
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>
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struct buffer: not_implemented<TagIn, TagOut>
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{};
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template <typename BoxIn, typename BoxOut>
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struct buffer<BoxIn, BoxOut, box_tag, box_tag>
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{
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template <typename Distance>
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static inline void apply(BoxIn const& box_in, Distance const& distance,
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Distance const& , BoxIn& box_out)
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{
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detail::buffer::buffer_box(box_in, distance, box_out);
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}
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};
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// Many things to do. Point is easy, other geometries require self intersections
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// For point, note that it should output as a polygon (like the rest). Buffers
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// of a set of geometries are often lateron combined using a "dissolve" operation.
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// Two points close to each other get a combined kidney shaped buffer then.
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} // namespace dispatch
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#endif // DOXYGEN_NO_DISPATCH
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/*!
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\brief \brief_calc{buffer}
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\ingroup buffer
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\details \details_calc{buffer, \det_buffer}.
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\tparam Input \tparam_geometry
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\tparam Output \tparam_geometry
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\tparam Distance \tparam_numeric
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\param geometry_in \param_geometry
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\param geometry_out \param_geometry
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\param distance The distance to be used for the buffer
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\param chord_length (optional) The length of the chord's in the generated arcs around points or bends
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\note Currently only implemented for box, the trivial case, but still useful
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\qbk{[include reference/algorithms/buffer.qbk]}
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*/
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template <typename Input, typename Output, typename Distance>
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inline void buffer(Input const& geometry_in, Output& geometry_out,
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Distance const& distance, Distance const& chord_length = -1)
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{
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concept::check<Input const>();
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concept::check<Output>();
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dispatch::buffer
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<
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Input,
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Output
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>::apply(geometry_in, distance, chord_length, geometry_out);
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}
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/*!
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\brief \brief_calc{buffer}
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\ingroup buffer
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\details \details_calc{return_buffer, \det_buffer}. \details_return{buffer}.
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\tparam Input \tparam_geometry
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\tparam Output \tparam_geometry
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\tparam Distance \tparam_numeric
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\param geometry \param_geometry
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\param distance The distance to be used for the buffer
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\param chord_length (optional) The length of the chord's in the generated arcs
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around points or bends
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\return \return_calc{buffer}
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*/
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template <typename Output, typename Input, typename Distance>
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Output return_buffer(Input const& geometry, Distance const& distance, Distance const& chord_length = -1)
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{
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concept::check<Input const>();
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concept::check<Output>();
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Output geometry_out;
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dispatch::buffer
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<
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Input,
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Output
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>::apply(geometry, distance, chord_length, geometry_out);
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return geometry_out;
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}
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_ALGORITHMS_BUFFER_HPP
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