Chris@102: // Boost.Geometry (aka GGL, Generic Geometry Library)
Chris@102: 
Chris@102: // Copyright (c) 2007-2014 Barend Gehrels, Amsterdam, the Netherlands.
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_GEOMETRY_POLICIES_RELATE_INTERSECTION_RATIOS_HPP
Chris@102: #define BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_INTERSECTION_RATIOS_HPP
Chris@102: 
Chris@102: 
Chris@102: #include <algorithm>
Chris@102: #include <string>
Chris@102: 
Chris@102: #include <boost/concept_check.hpp>
Chris@102: #include <boost/numeric/conversion/cast.hpp>
Chris@102: 
Chris@102: #include <boost/geometry/algorithms/detail/assign_indexed_point.hpp>
Chris@102: #include <boost/geometry/core/access.hpp>
Chris@102: #include <boost/geometry/strategies/side_info.hpp>
Chris@102: 
Chris@102: 
Chris@102: namespace boost { namespace geometry
Chris@102: {
Chris@102: 
Chris@102: namespace policies { namespace relate
Chris@102: {
Chris@102: 
Chris@102: 
Chris@102: /*!
Chris@102: \brief Policy returning segment ratios
Chris@102: \note Template argument FractionType should be a fraction_type<SegmentRatio>
Chris@102:  */
Chris@102: template
Chris@102: <
Chris@102:     typename FractionType
Chris@102: >
Chris@102: struct segments_intersection_ratios
Chris@102: {
Chris@102:     typedef FractionType return_type;
Chris@102: 
Chris@102:     template
Chris@102:     <
Chris@102:         typename Segment1,
Chris@102:         typename Segment2,
Chris@102:         typename SegmentIntersectionInfo
Chris@102:     >
Chris@102:     static inline return_type segments_crosses(side_info const&,
Chris@102:                     SegmentIntersectionInfo const& sinfo,
Chris@102:                     Segment1 const& , Segment2 const& )
Chris@102:     {
Chris@102:         return_type result;
Chris@102:         result.assign(sinfo);
Chris@102:         return result;
Chris@102:     }
Chris@102: 
Chris@102:     template <typename Segment1, typename Segment2, typename Ratio>
Chris@102:     static inline return_type segments_collinear(
Chris@102:         Segment1 const& , Segment2 const& ,
Chris@102:         Ratio const& ra_from_wrt_b, Ratio const& ra_to_wrt_b,
Chris@102:         Ratio const& rb_from_wrt_a, Ratio const& rb_to_wrt_a)
Chris@102:     {
Chris@102:         // We have only one result, for (potentially) two IP's,
Chris@102:         // so we take a first one
Chris@102:         return_type result;
Chris@102: 
Chris@102:         if (ra_from_wrt_b.on_segment())
Chris@102:         {
Chris@102:             result.assign(Ratio::zero(), ra_from_wrt_b);
Chris@102:         }
Chris@102:         else if (rb_from_wrt_a.in_segment())
Chris@102:         {
Chris@102:             result.assign(rb_from_wrt_a, Ratio::zero());
Chris@102:         }
Chris@102:         else if (ra_to_wrt_b.on_segment())
Chris@102:         {
Chris@102:             result.assign(Ratio::one(), ra_to_wrt_b);
Chris@102:         }
Chris@102:         else if (rb_to_wrt_a.in_segment())
Chris@102:         {
Chris@102:             result.assign(rb_to_wrt_a, Ratio::one());
Chris@102:         }
Chris@102: 
Chris@102:         return result;
Chris@102:     }
Chris@102: 
Chris@102:     static inline return_type disjoint()
Chris@102:     {
Chris@102:         return return_type();
Chris@102:     }
Chris@102:     static inline return_type error(std::string const&)
Chris@102:     {
Chris@102:         return return_type();
Chris@102:     }
Chris@102: 
Chris@102:     template <typename Segment>
Chris@102:     static inline return_type degenerate(Segment const& segment, bool)
Chris@102:     {
Chris@102:         return return_type();
Chris@102:     }
Chris@102: 
Chris@102:     template <typename Segment, typename Ratio>
Chris@102:     static inline return_type one_degenerate(Segment const& ,
Chris@102:             Ratio const& ratio, bool a_degenerate)
Chris@102:     {
Chris@102:         return_type result;
Chris@102:         if (a_degenerate)
Chris@102:         {
Chris@102:             // IP lies on ratio w.r.t. segment b
Chris@102:             result.assign(Ratio::zero(), ratio);
Chris@102:         }
Chris@102:         else
Chris@102:         {
Chris@102:             result.assign(ratio, Ratio::zero());
Chris@102:         }
Chris@102:         return result;
Chris@102:     }
Chris@102: 
Chris@102: };
Chris@102: 
Chris@102: 
Chris@102: }} // namespace policies::relate
Chris@102: 
Chris@102: }} // namespace boost::geometry
Chris@102: 
Chris@102: #endif // BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_INTERSECTION_RATIOS_HPP