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