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