// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2012-2014 Barend Gehrels, 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_STRATEGIES_CARTESIAN_BUFFER_JOIN_ROUND_BY_DIVIDE_HPP
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#define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_JOIN_ROUND_BY_DIVIDE_HPP
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#include <boost/geometry/core/cs.hpp>
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#include <boost/geometry/policies/compare.hpp>
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#include <boost/geometry/strategies/buffer.hpp>
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#include <boost/geometry/util/math.hpp>
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#include <boost/geometry/util/select_most_precise.hpp>
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#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_WARN
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#include <boost/geometry/io/wkt/wkt.hpp>
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#endif
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namespace boost { namespace geometry
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{
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namespace strategy { namespace buffer
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{
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class join_round_by_divide
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{
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public :
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inline join_round_by_divide(std::size_t max_level = 4)
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: m_max_level(max_level)
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{}
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template
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<
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typename PromotedType,
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typename Point,
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typename DistanceType,
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typename RangeOut
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>
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inline void mid_points(Point const& vertex,
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Point const& p1, Point const& p2,
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DistanceType const& buffer_distance,
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RangeOut& range_out,
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std::size_t level = 1) const
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{
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typedef typename coordinate_type<Point>::type coordinate_type;
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// Generate 'vectors'
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coordinate_type const vp1_x = get<0>(p1) - get<0>(vertex);
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coordinate_type const vp1_y = get<1>(p1) - get<1>(vertex);
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coordinate_type const vp2_x = (get<0>(p2) - get<0>(vertex));
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coordinate_type const vp2_y = (get<1>(p2) - get<1>(vertex));
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// Average them to generate vector in between
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coordinate_type const two = 2;
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coordinate_type const v_x = (vp1_x + vp2_x) / two;
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coordinate_type const v_y = (vp1_y + vp2_y) / two;
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PromotedType const length2 = geometry::math::sqrt(v_x * v_x + v_y * v_y);
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PromotedType prop = buffer_distance / length2;
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Point mid_point;
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set<0>(mid_point, get<0>(vertex) + v_x * prop);
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set<1>(mid_point, get<1>(vertex) + v_y * prop);
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if (level < m_max_level)
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{
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mid_points<PromotedType>(vertex, p1, mid_point, buffer_distance, range_out, level + 1);
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}
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range_out.push_back(mid_point);
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if (level < m_max_level)
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{
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mid_points<PromotedType>(vertex, mid_point, p2, buffer_distance, range_out, level + 1);
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}
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}
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template <typename Point, typename DistanceType, typename RangeOut>
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inline bool apply(Point const& ip, Point const& vertex,
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Point const& perp1, Point const& perp2,
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DistanceType const& buffer_distance,
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RangeOut& range_out) const
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{
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typedef typename coordinate_type<Point>::type coordinate_type;
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typedef typename geometry::select_most_precise
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<
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coordinate_type,
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double
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>::type promoted_type;
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geometry::equal_to<Point> equals;
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if (equals(perp1, perp2))
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{
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#ifdef BOOST_GEOMETRY_DEBUG_BUFFER_WARN
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std::cout << "Corner for equal points " << geometry::wkt(ip) << " " << geometry::wkt(perp1) << std::endl;
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#endif
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return false;
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}
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// Generate 'vectors'
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coordinate_type const vix = (get<0>(ip) - get<0>(vertex));
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coordinate_type const viy = (get<1>(ip) - get<1>(vertex));
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promoted_type const length_i = geometry::math::sqrt(vix * vix + viy * viy);
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promoted_type const bd = geometry::math::abs(buffer_distance);
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promoted_type prop = bd / length_i;
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Point bp;
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set<0>(bp, get<0>(vertex) + vix * prop);
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set<1>(bp, get<1>(vertex) + viy * prop);
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range_out.push_back(perp1);
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if (m_max_level > 1)
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{
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mid_points<promoted_type>(vertex, perp1, bp, bd, range_out);
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range_out.push_back(bp);
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mid_points<promoted_type>(vertex, bp, perp2, bd, range_out);
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}
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else if (m_max_level == 1)
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{
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range_out.push_back(bp);
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}
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range_out.push_back(perp2);
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return true;
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}
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template <typename NumericType>
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static inline NumericType max_distance(NumericType const& distance)
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{
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return distance;
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}
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private :
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std::size_t m_max_level;
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};
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}} // namespace strategy::buffer
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_JOIN_ROUND_BY_DIVIDE_HPP
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