115 lines
3.7 KiB
C++
115 lines
3.7 KiB
C++
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// Boost.Geometry (aka GGL, Generic Geometry Library)
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// Copyright (c) 2012-2014 Barend Gehrels, Amsterdam, the Netherlands.
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// This file was modified by Oracle on 2018.
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// Modifications copyright (c) 2018, Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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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_END_FLAT_HPP
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#define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP
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#include <boost/geometry/core/coordinate_type.hpp>
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#include <boost/geometry/strategies/buffer.hpp>
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#include <boost/geometry/strategies/tags.hpp>
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#include <boost/geometry/strategies/side.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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namespace boost { namespace geometry
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{
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namespace strategy { namespace buffer
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{
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/*!
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\brief Let the buffer create flat ends
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\ingroup strategies
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\details This strategy can be used as EndStrategy for the buffer algorithm.
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It creates a flat end for each linestring-end. It can be applied
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for (multi)linestrings. Also it is applicable for spikes in (multi)polygons.
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This strategy is only applicable for Cartesian coordinate systems.
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\qbk{
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[heading Example]
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[buffer_end_flat]
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[heading Output]
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[$img/strategies/buffer_end_flat.png]
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[heading See also]
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\* [link geometry.reference.algorithms.buffer.buffer_7_with_strategies buffer (with strategies)]
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\* [link geometry.reference.strategies.strategy_buffer_end_round end_round]
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}
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*/
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class end_flat
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{
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public :
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#ifndef DOXYGEN_SHOULD_SKIP_THIS
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//! Fills output_range with a flat end
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template <typename Point, typename RangeOut, typename DistanceStrategy>
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inline void apply(Point const& penultimate_point,
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Point const& perp_left_point,
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Point const& ultimate_point,
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Point const& perp_right_point,
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buffer_side_selector side,
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DistanceStrategy const& 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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promoted_type const dist_left = distance.apply(penultimate_point, ultimate_point, buffer_side_left);
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promoted_type const dist_right = distance.apply(penultimate_point, ultimate_point, buffer_side_right);
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bool reversed = (side == buffer_side_left && dist_right < 0 && -dist_right > dist_left)
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|| (side == buffer_side_right && dist_left < 0 && -dist_left > dist_right)
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;
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if (reversed)
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{
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range_out.push_back(perp_right_point);
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range_out.push_back(perp_left_point);
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}
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else
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{
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range_out.push_back(perp_left_point);
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range_out.push_back(perp_right_point);
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}
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// Don't add the ultimate_point (endpoint of the linestring).
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// The buffer might be generated completely at one side.
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// In other cases it does no harm but is further useless
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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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//! Returns the piece_type (flat end)
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static inline piece_type get_piece_type()
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{
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return buffered_flat_end;
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}
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#endif // DOXYGEN_SHOULD_SKIP_THIS
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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_END_FLAT_HPP
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