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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
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