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+// Boost.Geometry
+
+// Copyright (c) 2022 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_GEOGRAPHIC_BUFFER_SIDE_STRAIGHT_HPP
+#define BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_SIDE_STRAIGHT_HPP
+
+#include <cstddef>
+
+#include <boost/range/value_type.hpp>
+
+#include <boost/geometry/core/radian_access.hpp>
+
+#include <boost/geometry/srs/spheroid.hpp>
+#include <boost/geometry/strategies/buffer.hpp>
+#include <boost/geometry/strategies/geographic/buffer_helper.hpp>
+#include <boost/geometry/strategies/geographic/parameters.hpp>
+#include <boost/geometry/util/math.hpp>
+#include <boost/geometry/util/select_calculation_type.hpp>
+
+
+namespace boost { namespace geometry
+{
+
+namespace strategy { namespace buffer
+{
+
+/*!
+\brief Create a straight buffer along a side, on the Earth
+\ingroup strategies
+\details This strategy can be used as SideStrategy for the buffer algorithm.
+ */
+template
+<
+ typename FormulaPolicy = strategy::andoyer,
+ typename Spheroid = srs::spheroid<double>,
+ typename CalculationType = void
+>
+class geographic_side_straight
+{
+public :
+ //! \brief Constructs the strategy with a spheroid
+ //! \param spheroid The spheroid to be used
+ explicit inline geographic_side_straight(Spheroid const& spheroid)
+ : m_spheroid(spheroid)
+ {}
+
+ //! \brief Constructs the strategy
+ inline geographic_side_straight()
+ {}
+
+#ifndef DOXYGEN_SHOULD_SKIP_THIS
+ // Returns true if the buffer distance is always the same
+ static inline bool equidistant()
+ {
+ return true;
+ }
+
+
+ template
+ <
+ typename Point,
+ typename DistanceStrategy,
+ typename RangeOut
+ >
+ inline result_code apply(Point const& input_p1, Point const& input_p2,
+ buffer_side_selector side,
+ DistanceStrategy const& distance_strategy,
+ RangeOut& range_out) const
+ {
+ using calc_t = typename select_calculation_type
+ <
+ Point,
+ typename boost::range_value<RangeOut>::type,
+ CalculationType
+ >::type;
+
+ using helper = geographic_buffer_helper<FormulaPolicy, calc_t>;
+
+ calc_t const lon1_rad = get_as_radian<0>(input_p1);
+ calc_t const lat1_rad = get_as_radian<1>(input_p1);
+ calc_t const lon2_rad = get_as_radian<0>(input_p2);
+ calc_t const lat2_rad = get_as_radian<1>(input_p2);
+ if (lon1_rad == lon2_rad && lat1_rad == lat2_rad)
+ {
+ // Coordinates are simplified and therefore most often not equal.
+ // But if simplify is skipped, or for lines with two
+ // equal points, length is 0 and we cannot generate output.
+ return result_no_output;
+ }
+
+
+ // Measure the angle from p1 to p2 with the Inverse transformation,
+ // and subtract pi/2 to make it perpendicular.
+ auto const inv = helper::azimuth(lon1_rad, lat1_rad, input_p2, m_spheroid);
+ auto const angle = math::wrap_azimuth_in_radian(inv - geometry::math::half_pi<calc_t>());
+
+ // Calculate the distance and generate two points at that distance
+ auto const distance = distance_strategy.apply(input_p1, input_p2, side);
+ helper::append_point(lon1_rad, lat1_rad, distance, angle, m_spheroid, range_out);
+ helper::append_point(lon2_rad, lat2_rad, distance, angle, m_spheroid, range_out);
+
+ return result_normal;
+ }
+#endif // DOXYGEN_SHOULD_SKIP_THIS
+
+private :
+ Spheroid m_spheroid;
+};
+
+}} // namespace strategy::buffer
+
+}} // namespace boost::geometry
+
+#endif // BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_SIDE_STRAIGHT_HPP