1 // Boost.Geometry Index
2 //
3 // n-dimensional box-linestring intersection
4 //
5 // Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland.
6 //
7 // Use, modification and distribution is subject to the Boost Software License,
8 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
9 // http://www.boost.org/LICENSE_1_0.txt)
10
11 #ifndef BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_PATH_INTERSECTION_HPP
12 #define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_PATH_INTERSECTION_HPP
13
14 #include <boost/geometry/index/detail/algorithms/segment_intersection.hpp>
15
16 namespace boost { namespace geometry { namespace index { namespace detail {
17
18 namespace dispatch {
19
20 template <typename Indexable, typename Geometry, typename IndexableTag, typename GeometryTag>
21 struct path_intersection
22 {
23 BOOST_MPL_ASSERT_MSG((false), NOT_IMPLEMENTED_FOR_THIS_GEOMETRY_OR_INDEXABLE, (path_intersection));
24 };
25
26 // TODO: FP type must be used as a relative distance type!
27 // and default_distance_result can be some user-defined int type
28 // BUT! This code is experimental and probably won't be released at all
29 // since more flexible user-defined-nearest predicate should be added instead
30
31 template <typename Indexable, typename Segment>
32 struct path_intersection<Indexable, Segment, box_tag, segment_tag>
33 {
34 typedef typename default_distance_result<typename point_type<Segment>::type>::type comparable_distance_type;
35
applyboost::geometry::index::detail::dispatch::path_intersection36 static inline bool apply(Indexable const& b, Segment const& segment, comparable_distance_type & comparable_distance)
37 {
38 typedef typename point_type<Segment>::type point_type;
39 point_type p1, p2;
40 geometry::detail::assign_point_from_index<0>(segment, p1);
41 geometry::detail::assign_point_from_index<1>(segment, p2);
42 return index::detail::segment_intersection(b, p1, p2, comparable_distance);
43 }
44 };
45
46 template <typename Indexable, typename Linestring>
47 struct path_intersection<Indexable, Linestring, box_tag, linestring_tag>
48 {
49 typedef typename default_length_result<Linestring>::type comparable_distance_type;
50
applyboost::geometry::index::detail::dispatch::path_intersection51 static inline bool apply(Indexable const& b, Linestring const& path, comparable_distance_type & comparable_distance)
52 {
53 typedef typename ::boost::range_value<Linestring>::type point_type;
54 typedef typename ::boost::range_const_iterator<Linestring>::type const_iterator;
55 typedef typename ::boost::range_size<Linestring>::type size_type;
56
57 const size_type count = ::boost::size(path);
58
59 if ( count == 2 )
60 {
61 return index::detail::segment_intersection(b, *::boost::begin(path), *(::boost::begin(path)+1), comparable_distance);
62 }
63 else if ( 2 < count )
64 {
65 const_iterator it0 = ::boost::begin(path);
66 const_iterator it1 = ::boost::begin(path) + 1;
67 const_iterator last = ::boost::end(path);
68
69 comparable_distance = 0;
70
71 for ( ; it1 != last ; ++it0, ++it1 )
72 {
73 typename default_distance_result<point_type, point_type>::type
74 dist = geometry::distance(*it0, *it1);
75
76 comparable_distance_type rel_dist;
77 if ( index::detail::segment_intersection(b, *it0, *it1, rel_dist) )
78 {
79 comparable_distance += dist * rel_dist;
80 return true;
81 }
82 else
83 comparable_distance += dist;
84 }
85 }
86
87 return false;
88 }
89 };
90
91 } // namespace dispatch
92
93 template <typename Indexable, typename SegmentOrLinestring>
94 struct default_path_intersection_distance_type
95 {
96 typedef typename dispatch::path_intersection<
97 Indexable, SegmentOrLinestring,
98 typename tag<Indexable>::type,
99 typename tag<SegmentOrLinestring>::type
100 >::comparable_distance_type type;
101 };
102
103 template <typename Indexable, typename SegmentOrLinestring> inline
path_intersection(Indexable const & b,SegmentOrLinestring const & path,typename default_path_intersection_distance_type<Indexable,SegmentOrLinestring>::type & comparable_distance)104 bool path_intersection(Indexable const& b,
105 SegmentOrLinestring const& path,
106 typename default_path_intersection_distance_type<Indexable, SegmentOrLinestring>::type & comparable_distance)
107 {
108 // TODO check Indexable and Linestring concepts
109
110 return dispatch::path_intersection<
111 Indexable, SegmentOrLinestring,
112 typename tag<Indexable>::type,
113 typename tag<SegmentOrLinestring>::type
114 >::apply(b, path, comparable_distance);
115 }
116
117 }}}} // namespace boost::geometry::index::detail
118
119 #endif // BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_PATH_INTERSECTION_HPP
120