// Boost.Geometry
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// Copyright (c) 2018-2019 Barend Gehrels, Amsterdam, the Netherlands.
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// This file was modified by Oracle on 2020.
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// Modifications copyright (c) 2020 Oracle and/or its affiliates.
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// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
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// Use, modification and distribution is subject to the Boost Software License,
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// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
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// http://www.boost.org/LICENSE_1_0.txt)
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#ifndef BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
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#define BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
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#include <cstddef>
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#include <boost/range/value_type.hpp>
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#include <boost/geometry/util/math.hpp>
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#include <boost/geometry/util/select_calculation_type.hpp>
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#include <boost/geometry/strategies/buffer.hpp>
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namespace boost { namespace geometry
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{
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namespace strategy { namespace buffer
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{
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/*!
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\brief Create a circular buffer around a point, on the Earth
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\ingroup strategies
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\details This strategy can be used as PointStrategy for the buffer algorithm.
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It creates a circular buffer around a point, on the Earth. It can be applied
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for points and multi_points.
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\qbk{
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[heading Example]
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[buffer_geographic_point_circle]
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[buffer_geographic_point_circle_output]
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[heading See also]
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\* [link geometry.reference.algorithms.buffer.buffer_7_with_strategies buffer (with strategies)]
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\* [link geometry.reference.strategies.strategy_buffer_point_circle point_circle]
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\* [link geometry.reference.strategies.strategy_buffer_point_square point_square]
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}
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*/
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template
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<
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typename FormulaPolicy = strategy::andoyer,
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typename Spheroid = srs::spheroid<double>,
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typename CalculationType = void
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>
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class geographic_point_circle
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{
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public :
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//! \brief Constructs the strategy
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//! \param count number of points for the created circle (if count
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//! is smaller than 3, count is internally set to 3)
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explicit geographic_point_circle(std::size_t count = 90)
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: m_count((count < 3u) ? 3u : count)
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{}
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#ifndef DOXYGEN_SHOULD_SKIP_THIS
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//! Fills output_range with a circle around point using distance_strategy
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template
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<
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typename Point,
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typename OutputRange,
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typename DistanceStrategy
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>
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inline void apply(Point const& point,
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DistanceStrategy const& distance_strategy,
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OutputRange& output_range) const
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{
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typedef typename boost::range_value<OutputRange>::type output_point_type;
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typedef typename select_calculation_type
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<
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Point, output_point_type,
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CalculationType
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//double
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>::type calculation_type;
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calculation_type const buffer_distance = distance_strategy.apply(point, point,
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strategy::buffer::buffer_side_left);
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typedef typename FormulaPolicy::template direct
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<
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calculation_type, true, false, false, false
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> direct_t;
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calculation_type const two_pi = geometry::math::two_pi<calculation_type>();
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calculation_type const pi = geometry::math::pi<calculation_type>();
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calculation_type const diff = two_pi / calculation_type(m_count);
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// TODO: after calculation of some angles is corrected,
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// we can start at 0.0
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calculation_type angle = 0.001;
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for (std::size_t i = 0; i < m_count; i++, angle += diff)
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{
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if (angle > pi)
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{
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angle -= two_pi;
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}
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typename direct_t::result_type
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dir_r = direct_t::apply(get_as_radian<0>(point), get_as_radian<1>(point),
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buffer_distance, angle,
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m_spheroid);
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output_point_type p;
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set_from_radian<0>(p, dir_r.lon2);
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set_from_radian<1>(p, dir_r.lat2);
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output_range.push_back(p);
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}
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{
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// Close the range
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const output_point_type p = output_range.front();
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output_range.push_back(p);
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}
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}
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#endif // DOXYGEN_SHOULD_SKIP_THIS
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private :
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std::size_t m_count;
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Spheroid m_spheroid;
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};
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}} // namespace strategy::buffer
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}} // namespace boost::geometry
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#endif // BOOST_GEOMETRY_STRATEGIES_GEOGRAPHIC_BUFFER_POINT_CIRCLE_HPP
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