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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2007-2014 Barend Gehrels, Amsterdam, the Netherlands. | |
4 | ||
5 | // Use, modification and distribution is subject to the Boost Software License, | |
6 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
7 | // http://www.boost.org/LICENSE_1_0.txt) | |
8 | ||
9 | #ifndef BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_INTERSECTION_RATIOS_HPP | |
10 | #define BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_INTERSECTION_RATIOS_HPP | |
11 | ||
12 | ||
13 | #include <algorithm> | |
14 | #include <string> | |
15 | ||
16 | #include <boost/concept_check.hpp> | |
17 | #include <boost/numeric/conversion/cast.hpp> | |
18 | ||
19 | #include <boost/geometry/algorithms/detail/assign_indexed_point.hpp> | |
20 | #include <boost/geometry/core/access.hpp> | |
21 | #include <boost/geometry/strategies/side_info.hpp> | |
22 | ||
23 | ||
24 | namespace boost { namespace geometry | |
25 | { | |
26 | ||
27 | namespace policies { namespace relate | |
28 | { | |
29 | ||
30 | ||
31 | /*! | |
32 | \brief Policy returning segment ratios | |
33 | \note Template argument FractionType should be a fraction_type<SegmentRatio> | |
34 | */ | |
35 | template | |
36 | < | |
37 | typename FractionType | |
38 | > | |
39 | struct segments_intersection_ratios | |
40 | { | |
41 | typedef FractionType return_type; | |
42 | ||
43 | template | |
44 | < | |
45 | typename Segment1, | |
46 | typename Segment2, | |
47 | typename SegmentIntersectionInfo | |
48 | > | |
49 | static inline return_type segments_crosses(side_info const&, | |
50 | SegmentIntersectionInfo const& sinfo, | |
51 | Segment1 const& , Segment2 const& ) | |
52 | { | |
53 | return_type result; | |
54 | result.assign(sinfo); | |
55 | return result; | |
56 | } | |
57 | ||
58 | template <typename Segment1, typename Segment2, typename Ratio> | |
59 | static inline return_type segments_collinear( | |
60 | Segment1 const& , Segment2 const& , | |
61 | Ratio const& ra_from_wrt_b, Ratio const& ra_to_wrt_b, | |
62 | Ratio const& rb_from_wrt_a, Ratio const& rb_to_wrt_a) | |
63 | { | |
64 | // We have only one result, for (potentially) two IP's, | |
65 | // so we take a first one | |
66 | return_type result; | |
67 | ||
68 | if (ra_from_wrt_b.on_segment()) | |
69 | { | |
70 | result.assign(Ratio::zero(), ra_from_wrt_b); | |
71 | } | |
72 | else if (rb_from_wrt_a.in_segment()) | |
73 | { | |
74 | result.assign(rb_from_wrt_a, Ratio::zero()); | |
75 | } | |
76 | else if (ra_to_wrt_b.on_segment()) | |
77 | { | |
78 | result.assign(Ratio::one(), ra_to_wrt_b); | |
79 | } | |
80 | else if (rb_to_wrt_a.in_segment()) | |
81 | { | |
82 | result.assign(rb_to_wrt_a, Ratio::one()); | |
83 | } | |
84 | ||
85 | return result; | |
86 | } | |
87 | ||
88 | static inline return_type disjoint() | |
89 | { | |
90 | return return_type(); | |
91 | } | |
92 | static inline return_type error(std::string const&) | |
93 | { | |
94 | return return_type(); | |
95 | } | |
96 | ||
97 | template <typename Segment> | |
98 | static inline return_type degenerate(Segment const& segment, bool) | |
99 | { | |
100 | return return_type(); | |
101 | } | |
102 | ||
103 | template <typename Segment, typename Ratio> | |
104 | static inline return_type one_degenerate(Segment const& , | |
105 | Ratio const& ratio, bool a_degenerate) | |
106 | { | |
107 | return_type result; | |
108 | if (a_degenerate) | |
109 | { | |
110 | // IP lies on ratio w.r.t. segment b | |
111 | result.assign(Ratio::zero(), ratio); | |
112 | } | |
113 | else | |
114 | { | |
115 | result.assign(ratio, Ratio::zero()); | |
116 | } | |
117 | return result; | |
118 | } | |
119 | ||
120 | }; | |
121 | ||
122 | ||
123 | }} // namespace policies::relate | |
124 | ||
125 | }} // namespace boost::geometry | |
126 | ||
127 | #endif // BOOST_GEOMETRY_GEOMETRY_POLICIES_RELATE_INTERSECTION_RATIOS_HPP |