Chris@102: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@102: 
Chris@102: // Copyright (c) 2012-2015 Barend Gehrels, Amsterdam, the Netherlands.
Chris@102: 
Chris@102: // This file was modified by Oracle on 2015.
Chris@102: // Modifications copyright (c) 2015, Oracle and/or its affiliates.
Chris@102: 
Chris@102: // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
Chris@102: 
Chris@102: // Use, modification and distribution is subject to the Boost Software License,
Chris@102: // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
Chris@102: // http://www.boost.org/LICENSE_1_0.txt)
Chris@102: 
Chris@102: #ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_POINT_CIRCLE_HPP
Chris@102: #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_POINT_CIRCLE_HPP
Chris@102: 
Chris@102: #include <cstddef>
Chris@102: 
Chris@102: #include <boost/range.hpp>
Chris@102: 
Chris@102: #include <boost/geometry/util/math.hpp>
Chris@102: 
Chris@102: #include <boost/geometry/strategies/buffer.hpp>
Chris@102: 
Chris@102: 
Chris@102: namespace boost { namespace geometry
Chris@102: {
Chris@102: 
Chris@102: namespace strategy { namespace buffer
Chris@102: {
Chris@102: 
Chris@102: /*!
Chris@102: \brief Create a circular buffer around a point
Chris@102: \ingroup strategies
Chris@102: \details This strategy can be used as PointStrategy for the buffer algorithm.
Chris@102:     It creates a circular buffer around a point. It can be applied
Chris@102:     for points and multi_points, but also for a linestring (if it is degenerate,
Chris@102:     so consisting of only one point) and for polygons (if it is degenerate).
Chris@102:     This strategy is only applicable for Cartesian coordinate systems.
Chris@102: 
Chris@102: \qbk{
Chris@102: [heading Example]
Chris@102: [buffer_point_circle]
Chris@102: [heading Output]
Chris@102: [$img/strategies/buffer_point_circle.png]
Chris@102: [heading See also]
Chris@102: \* [link geometry.reference.algorithms.buffer.buffer_7_with_strategies buffer (with strategies)]
Chris@102: \* [link geometry.reference.strategies.strategy_buffer_point_square point_square]
Chris@102: }
Chris@102:  */
Chris@102: class point_circle
Chris@102: {
Chris@102: public :
Chris@102:     //! \brief Constructs the strategy
Chris@102:     //! \param count number of points for the created circle (if count
Chris@102:     //! is smaller than 3, count is internally set to 3)
Chris@102:     explicit point_circle(std::size_t count = 90)
Chris@102:         : m_count((count < 3u) ? 3u : count)
Chris@102:     {}
Chris@102: 
Chris@102: #ifndef DOXYGEN_SHOULD_SKIP_THIS
Chris@102:     //! Fills output_range with a circle around point using distance_strategy
Chris@102:     template
Chris@102:     <
Chris@102:         typename Point,
Chris@102:         typename OutputRange,
Chris@102:         typename DistanceStrategy
Chris@102:     >
Chris@102:     inline void apply(Point const& point,
Chris@102:                 DistanceStrategy const& distance_strategy,
Chris@102:                 OutputRange& output_range) const
Chris@102:     {
Chris@102:         typedef typename boost::range_value<OutputRange>::type output_point_type;
Chris@102: 
Chris@102:         typedef typename geometry::select_most_precise
Chris@102:             <
Chris@102:                 typename geometry::select_most_precise
Chris@102:                     <
Chris@102:                         typename geometry::coordinate_type<Point>::type,
Chris@102:                         typename geometry::coordinate_type<output_point_type>::type
Chris@102:                     >::type,
Chris@102:                 double
Chris@102:             >::type promoted_type;
Chris@102: 
Chris@102:         promoted_type const buffer_distance = distance_strategy.apply(point, point,
Chris@102:                         strategy::buffer::buffer_side_left);
Chris@102: 
Chris@102:         promoted_type const two = 2.0;
Chris@102:         promoted_type const two_pi = two * geometry::math::pi<promoted_type>();
Chris@102: 
Chris@102:         promoted_type const diff = two_pi / promoted_type(m_count);
Chris@102:         promoted_type a = 0;
Chris@102: 
Chris@102:         for (std::size_t i = 0; i < m_count; i++, a -= diff)
Chris@102:         {
Chris@102:             output_point_type p;
Chris@102:             set<0>(p, get<0>(point) + buffer_distance * cos(a));
Chris@102:             set<1>(p, get<1>(point) + buffer_distance * sin(a));
Chris@102:             output_range.push_back(p);
Chris@102:         }
Chris@102: 
Chris@102:         // Close it:
Chris@102:         output_range.push_back(output_range.front());
Chris@102:     }
Chris@102: #endif // DOXYGEN_SHOULD_SKIP_THIS
Chris@102: 
Chris@102: private :
Chris@102:     std::size_t m_count;
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: }} // namespace strategy::buffer
Chris@102: 
Chris@102: }} // namespace boost::geometry
Chris@102: 
Chris@102: #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_BUFFER_POINT_CIRCLE_HPP