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- // Boost.Geometry (aka GGL, Generic Geometry Library)
- // Copyright (c) 2008-2014 Bruno Lalande, Paris, France.
- // Copyright (c) 2008-2014 Barend Gehrels, Amsterdam, the Netherlands.
- // Copyright (c) 2009-2014 Mateusz Loskot, London, UK.
- // This file was modified by Oracle on 2014, 2018, 2019.
- // Modifications copyright (c) 2014-2019, Oracle and/or its affiliates.
- // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
- // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
- // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
- // (geolib/GGL), copyright (c) 1995-2010 Geodan, 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_CARTESIAN_DISTANCE_PROJECTED_POINT_HPP
- #define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DISTANCE_PROJECTED_POINT_HPP
- #include <boost/concept_check.hpp>
- #include <boost/core/ignore_unused.hpp>
- #include <boost/mpl/if.hpp>
- #include <boost/type_traits/is_void.hpp>
- #include <boost/geometry/core/access.hpp>
- #include <boost/geometry/core/point_type.hpp>
- #include <boost/geometry/algorithms/convert.hpp>
- #include <boost/geometry/arithmetic/arithmetic.hpp>
- #include <boost/geometry/arithmetic/dot_product.hpp>
- #include <boost/geometry/strategies/tags.hpp>
- #include <boost/geometry/strategies/distance.hpp>
- #include <boost/geometry/strategies/default_distance_result.hpp>
- #include <boost/geometry/strategies/cartesian/distance_pythagoras.hpp>
- #include <boost/geometry/strategies/cartesian/point_in_point.hpp>
- #include <boost/geometry/strategies/cartesian/intersection.hpp>
- #include <boost/geometry/util/select_coordinate_type.hpp>
- // Helper geometry (projected point on line)
- #include <boost/geometry/geometries/point.hpp>
- namespace boost { namespace geometry
- {
- namespace strategy { namespace distance
- {
- /*!
- \brief Strategy for distance point to segment
- \ingroup strategies
- \details Calculates distance using projected-point method, and (optionally) Pythagoras
- \author Adapted from: http://geometryalgorithms.com/Archive/algorithm_0102/algorithm_0102.htm
- \tparam CalculationType \tparam_calculation
- \tparam Strategy underlying point-point distance strategy
- \par Concepts for Strategy:
- - cartesian_distance operator(Point,Point)
- \note If the Strategy is a "comparable::pythagoras", this strategy
- automatically is a comparable projected_point strategy (so without sqrt)
- \qbk{
- [heading See also]
- [link geometry.reference.algorithms.distance.distance_3_with_strategy distance (with strategy)]
- }
- */
- template
- <
- typename CalculationType = void,
- typename Strategy = pythagoras<CalculationType>
- >
- class projected_point
- {
- public :
- typedef within::cartesian_point_point equals_point_point_strategy_type;
- typedef intersection::cartesian_segments
- <
- CalculationType
- > relate_segment_segment_strategy_type;
- static inline relate_segment_segment_strategy_type get_relate_segment_segment_strategy()
- {
- return relate_segment_segment_strategy_type();
- }
- typedef within::cartesian_winding
- <
- void, void, CalculationType
- > point_in_geometry_strategy_type;
- static inline point_in_geometry_strategy_type get_point_in_geometry_strategy()
- {
- return point_in_geometry_strategy_type();
- }
- // The three typedefs below are necessary to calculate distances
- // from segments defined in integer coordinates.
- // Integer coordinates can still result in FP distances.
- // There is a division, which must be represented in FP.
- // So promote.
- template <typename Point, typename PointOfSegment>
- struct calculation_type
- : promote_floating_point
- <
- typename strategy::distance::services::return_type
- <
- Strategy,
- Point,
- PointOfSegment
- >::type
- >
- {};
- template <typename Point, typename PointOfSegment>
- inline typename calculation_type<Point, PointOfSegment>::type
- apply(Point const& p, PointOfSegment const& p1, PointOfSegment const& p2) const
- {
- assert_dimension_equal<Point, PointOfSegment>();
- typedef typename calculation_type<Point, PointOfSegment>::type calculation_type;
- // A projected point of points in Integer coordinates must be able to be
- // represented in FP.
- typedef model::point
- <
- calculation_type,
- dimension<PointOfSegment>::value,
- typename coordinate_system<PointOfSegment>::type
- > fp_point_type;
- // For convenience
- typedef fp_point_type fp_vector_type;
- /*
- Algorithm [p: (px,py), p1: (x1,y1), p2: (x2,y2)]
- VECTOR v(x2 - x1, y2 - y1)
- VECTOR w(px - x1, py - y1)
- c1 = w . v
- c2 = v . v
- b = c1 / c2
- RETURN POINT(x1 + b * vx, y1 + b * vy)
- */
- // v is multiplied below with a (possibly) FP-value, so should be in FP
- // For consistency we define w also in FP
- fp_vector_type v, w, projected;
- geometry::convert(p2, v);
- geometry::convert(p, w);
- geometry::convert(p1, projected);
- subtract_point(v, projected);
- subtract_point(w, projected);
- Strategy strategy;
- boost::ignore_unused(strategy);
- calculation_type const zero = calculation_type();
- calculation_type const c1 = dot_product(w, v);
- if (c1 <= zero)
- {
- return strategy.apply(p, p1);
- }
- calculation_type const c2 = dot_product(v, v);
- if (c2 <= c1)
- {
- return strategy.apply(p, p2);
- }
- // See above, c1 > 0 AND c2 > c1 so: c2 != 0
- calculation_type const b = c1 / c2;
- multiply_value(v, b);
- add_point(projected, v);
- return strategy.apply(p, projected);
- }
- template <typename CT>
- inline CT vertical_or_meridian(CT const& lat1, CT const& lat2) const
- {
- return lat1 - lat2;
- }
- };
- #ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
- namespace services
- {
- template <typename CalculationType, typename Strategy>
- struct tag<projected_point<CalculationType, Strategy> >
- {
- typedef strategy_tag_distance_point_segment type;
- };
- template <typename CalculationType, typename Strategy, typename P, typename PS>
- struct return_type<projected_point<CalculationType, Strategy>, P, PS>
- : projected_point<CalculationType, Strategy>::template calculation_type<P, PS>
- {};
- template <typename CalculationType, typename Strategy>
- struct comparable_type<projected_point<CalculationType, Strategy> >
- {
- // Define a projected_point strategy with its underlying point-point-strategy
- // being comparable
- typedef projected_point
- <
- CalculationType,
- typename comparable_type<Strategy>::type
- > type;
- };
- template <typename CalculationType, typename Strategy>
- struct get_comparable<projected_point<CalculationType, Strategy> >
- {
- typedef typename comparable_type
- <
- projected_point<CalculationType, Strategy>
- >::type comparable_type;
- public :
- static inline comparable_type apply(projected_point<CalculationType, Strategy> const& )
- {
- return comparable_type();
- }
- };
- template <typename CalculationType, typename Strategy, typename P, typename PS>
- struct result_from_distance<projected_point<CalculationType, Strategy>, P, PS>
- {
- private :
- typedef typename return_type<projected_point<CalculationType, Strategy>, P, PS>::type return_type;
- public :
- template <typename T>
- static inline return_type apply(projected_point<CalculationType, Strategy> const& , T const& value)
- {
- Strategy s;
- return result_from_distance<Strategy, P, PS>::apply(s, value);
- }
- };
- // Get default-strategy for point-segment distance calculation
- // while still have the possibility to specify point-point distance strategy (PPS)
- // It is used in algorithms/distance.hpp where users specify PPS for distance
- // of point-to-segment or point-to-linestring.
- // Convenient for geographic coordinate systems especially.
- template <typename Point, typename PointOfSegment, typename Strategy>
- struct default_strategy
- <
- point_tag, segment_tag, Point, PointOfSegment,
- cartesian_tag, cartesian_tag, Strategy
- >
- {
- typedef strategy::distance::projected_point
- <
- void,
- typename boost::mpl::if_
- <
- boost::is_void<Strategy>,
- typename default_strategy
- <
- point_tag, point_tag, Point, PointOfSegment,
- cartesian_tag, cartesian_tag
- >::type,
- Strategy
- >::type
- > type;
- };
- template <typename PointOfSegment, typename Point, typename Strategy>
- struct default_strategy
- <
- segment_tag, point_tag, PointOfSegment, Point,
- cartesian_tag, cartesian_tag, Strategy
- >
- {
- typedef typename default_strategy
- <
- point_tag, segment_tag, Point, PointOfSegment,
- cartesian_tag, cartesian_tag, Strategy
- >::type type;
- };
- } // namespace services
- #endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
- }} // namespace strategy::distance
- }} // namespace boost::geometry
- #endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_DISTANCE_PROJECTED_POINT_HPP
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