Chris@102: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@102: 
Chris@102: // Copyright (c) 2012-2014 Barend Gehrels, Amsterdam, the Netherlands.
Chris@102: 
Chris@102: // Use, modification and distribution is subject to the Boost Software License,
Chris@102: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: 
Chris@102: #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP
Chris@102: #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP
Chris@102: 
Chris@102: #include <boost/geometry/core/cs.hpp>
Chris@102: #include <boost/geometry/strategies/tags.hpp>
Chris@102: #include <boost/geometry/strategies/side.hpp>
Chris@102: #include <boost/geometry/util/math.hpp>
Chris@102: #include <boost/geometry/util/select_most_precise.hpp>
Chris@102: 
Chris@102: #include <boost/geometry/strategies/buffer.hpp>
Chris@102: 
Chris@102: 
Chris@102: 
Chris@102: namespace boost { namespace geometry
Chris@102: {
Chris@102: 
Chris@102: 
Chris@102: namespace strategy { namespace buffer
Chris@102: {
Chris@102: 
Chris@102: 
Chris@102: /*!
Chris@102: \brief Let the buffer create flat ends
Chris@102: \ingroup strategies
Chris@102: \details This strategy can be used as EndStrategy for the buffer algorithm.
Chris@102:     It creates a flat end for each linestring-end. It can be applied
Chris@102:     for (multi)linestrings. Also it is applicable for spikes in (multi)polygons.
Chris@102:     This strategy is only applicable for Cartesian coordinate systems.
Chris@102: 
Chris@102: \qbk{
Chris@102: [heading Example]
Chris@102: [buffer_end_flat]
Chris@102: [heading Output]
Chris@102: [$img/strategies/buffer_end_flat.png]
Chris@102: [heading See also]
Chris@102: \* [link geometry.reference.algorithms.buffer.buffer_7_with_strategies buffer (with strategies)]
Chris@102: \* [link geometry.reference.strategies.strategy_buffer_end_round end_round]
Chris@102: }
Chris@102:  */
Chris@102: class end_flat
Chris@102: {
Chris@102: 
Chris@102: public :
Chris@102: 
Chris@102: #ifndef DOXYGEN_SHOULD_SKIP_THIS
Chris@102:     //! Fills output_range with a flat end
Chris@102:     template <typename Point, typename RangeOut, typename DistanceStrategy>
Chris@102:     inline void apply(Point const& penultimate_point,
Chris@102:                 Point const& perp_left_point,
Chris@102:                 Point const& ultimate_point,
Chris@102:                 Point const& perp_right_point,
Chris@102:                 buffer_side_selector side,
Chris@102:                 DistanceStrategy const& distance,
Chris@102:                 RangeOut& range_out) const
Chris@102:     {
Chris@102:         typedef typename coordinate_type<Point>::type coordinate_type;
Chris@102: 
Chris@102:         typedef typename geometry::select_most_precise
Chris@102:         <
Chris@102:             coordinate_type,
Chris@102:             double
Chris@102:         >::type promoted_type;
Chris@102: 
Chris@102:         promoted_type const dist_left = distance.apply(penultimate_point, ultimate_point, buffer_side_left);
Chris@102:         promoted_type const dist_right = distance.apply(penultimate_point, ultimate_point, buffer_side_right);
Chris@102: 
Chris@102:         bool reversed = (side == buffer_side_left && dist_right < 0 && -dist_right > dist_left)
Chris@102:                     || (side == buffer_side_right && dist_left < 0 && -dist_left > dist_right)
Chris@102:                     ;
Chris@102:         if (reversed)
Chris@102:         {
Chris@102:             range_out.push_back(perp_right_point);
Chris@102:             range_out.push_back(perp_left_point);
Chris@102:         }
Chris@102:         else
Chris@102:         {
Chris@102:             range_out.push_back(perp_left_point);
Chris@102:             range_out.push_back(perp_right_point);
Chris@102:         }
Chris@102:         // Don't add the ultimate_point (endpoint of the linestring).
Chris@102:         // The buffer might be generated completely at one side.
Chris@102:         // In other cases it does no harm but is further useless
Chris@102:     }
Chris@102: 
Chris@102:     template <typename NumericType>
Chris@102:     static inline NumericType max_distance(NumericType const& distance)
Chris@102:     {
Chris@102:         return distance;
Chris@102:     }
Chris@102: 
Chris@102:     //! Returns the piece_type (flat end)
Chris@102:     static inline piece_type get_piece_type()
Chris@102:     {
Chris@102:         return buffered_flat_end;
Chris@102:     }
Chris@102: #endif // DOXYGEN_SHOULD_SKIP_THIS
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: }} // namespace strategy::buffer
Chris@102: 
Chris@102: }} // namespace boost::geometry
Chris@102: 
Chris@102: #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_END_FLAT_HPP