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Diffstat (limited to 'boost/geometry/strategies/geographic/buffer_join_miter.hpp')
-rw-r--r-- | boost/geometry/strategies/geographic/buffer_join_miter.hpp | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/boost/geometry/strategies/geographic/buffer_join_miter.hpp b/boost/geometry/strategies/geographic/buffer_join_miter.hpp new file mode 100644 index 0000000000..b479f5fb57 --- /dev/null +++ b/boost/geometry/strategies/geographic/buffer_join_miter.hpp @@ -0,0 +1,132 @@ +// 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_JOIN_MITER_HPP +#define BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_JOIN_MITER_HPP + +#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 +{ + +template +< + typename FormulaPolicy = strategy::andoyer, + typename Spheroid = srs::spheroid<double>, + typename CalculationType = void +> +class geographic_join_miter +{ +public : + + //! \brief Constructs the strategy with a spheroid + //! \param spheroid The spheroid to be used + //! \param miter_limit The miter limit, to avoid excessively long miters around sharp corners + explicit inline geographic_join_miter(Spheroid const& spheroid, + double miter_limit = 5.0) + : m_spheroid(spheroid) + , m_miter_limit(valid_limit(miter_limit)) + {} + + //! \brief Constructs the strategy + //! \param miter_limit The miter limit, to avoid excessively long miters around sharp corners + explicit inline geographic_join_miter(double miter_limit = 5.0) + : m_miter_limit(valid_limit(miter_limit)) + {} + +#ifndef DOXYGEN_SHOULD_SKIP_THIS + //! Fills output_range with a sharp shape around a vertex + template <typename Point, typename DistanceType, typename RangeOut> + inline bool apply(Point const& , Point const& vertex, + Point const& perp1, Point const& perp2, + DistanceType const& buffer_distance, + 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 lon_rad = get_as_radian<0>(vertex); + calc_t const lat_rad = get_as_radian<1>(vertex); + + calc_t first_azimuth; + calc_t angle_diff; + if (! helper::calculate_angles(lon_rad, lat_rad, perp1, perp2, m_spheroid, + angle_diff, first_azimuth)) + { + return false; + } + + calc_t const half = 0.5; + calc_t const half_angle_diff = half * angle_diff; + calc_t const azi = math::wrap_azimuth_in_radian(first_azimuth + half_angle_diff); + + calc_t const cos_angle = std::cos(half_angle_diff); + + if (cos_angle == 0) + { + // It is opposite, perp1==perp2, do not generate a miter cap + return false; + } + + // If it is sharp (angle close to 0), the distance will become too high and will be capped. + calc_t const max_distance = m_miter_limit * geometry::math::abs(buffer_distance); + calc_t const distance = (std::min)(max_distance, buffer_distance / cos_angle); + + range_out.push_back(perp1); + helper::append_point(lon_rad, lat_rad, distance, azi, m_spheroid, range_out); + range_out.push_back(perp2); + return true; + } + + template <typename NumericType> + inline NumericType max_distance(NumericType const& distance) const + { + return distance * m_miter_limit; + } + +#endif // DOXYGEN_SHOULD_SKIP_THIS + +private : + double valid_limit(double miter_limit) const + { + if (miter_limit < 1.0) + { + // It should always exceed the buffer distance + miter_limit = 1.0; + } + return miter_limit; + } + + Spheroid m_spheroid; + double m_miter_limit; +}; + +}} // namespace strategy::buffer + +}} // namespace boost::geometry + +#endif // BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_JOIN_MITER_HPP |