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1 | // Boost.Geometry Index |
2 | // | |
3 | // squared distance between point and centroid of the box or point | |
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_COMPARABLE_DISTANCE_CENTROID_HPP | |
12 | #define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_COMPARABLE_DISTANCE_CENTROID_HPP | |
13 | ||
14 | #include <boost/geometry/index/detail/algorithms/sum_for_indexable.hpp> | |
15 | #include <boost/geometry/index/detail/algorithms/diff_abs.hpp> | |
16 | ||
17 | namespace boost { namespace geometry { namespace index { namespace detail { | |
18 | ||
19 | struct comparable_distance_centroid_tag {}; | |
20 | ||
21 | template < | |
22 | typename Point, | |
23 | typename PointIndexable, | |
24 | size_t N> | |
25 | struct sum_for_indexable<Point, PointIndexable, point_tag, comparable_distance_centroid_tag, N> | |
26 | { | |
27 | typedef typename geometry::default_comparable_distance_result<Point, PointIndexable>::type result_type; | |
28 | ||
29 | inline static result_type apply(Point const& pt, PointIndexable const& i) | |
30 | { | |
31 | return geometry::comparable_distance(pt, i); | |
32 | } | |
33 | }; | |
34 | ||
35 | template < | |
36 | typename Point, | |
37 | typename BoxIndexable, | |
38 | size_t DimensionIndex> | |
39 | struct sum_for_indexable_dimension<Point, BoxIndexable, box_tag, comparable_distance_centroid_tag, DimensionIndex> | |
40 | { | |
41 | typedef typename geometry::default_comparable_distance_result<Point, BoxIndexable>::type result_type; | |
42 | ||
43 | inline static result_type apply(Point const& pt, BoxIndexable const& i) | |
44 | { | |
45 | typedef typename coordinate_type<Point>::type point_coord_t; | |
46 | typedef typename coordinate_type<BoxIndexable>::type indexable_coord_t; | |
47 | ||
48 | point_coord_t pt_c = geometry::get<DimensionIndex>(pt); | |
49 | indexable_coord_t ind_c_min = geometry::get<geometry::min_corner, DimensionIndex>(i); | |
50 | indexable_coord_t ind_c_max = geometry::get<geometry::max_corner, DimensionIndex>(i); | |
51 | ||
52 | indexable_coord_t ind_c_avg = ind_c_min + (ind_c_max - ind_c_min) / 2; | |
53 | // TODO: awulkiew - is (ind_c_min + ind_c_max) / 2 safe? | |
54 | ||
55 | result_type diff = detail::diff_abs(ind_c_avg, pt_c); | |
56 | ||
57 | return diff * diff; | |
58 | } | |
59 | }; | |
60 | ||
61 | template <typename Point, typename Indexable> | |
62 | typename geometry::default_comparable_distance_result<Point, Indexable>::type | |
63 | comparable_distance_centroid(Point const& pt, Indexable const& i) | |
64 | { | |
65 | return detail::sum_for_indexable< | |
66 | Point, | |
67 | Indexable, | |
68 | typename tag<Indexable>::type, | |
69 | detail::comparable_distance_centroid_tag, | |
70 | dimension<Indexable>::value | |
71 | >::apply(pt, i); | |
72 | } | |
73 | ||
74 | }}}} // namespace boost::geometry::index::detail | |
75 | ||
76 | #endif // #define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_COMPARABLE_DISTANCE_CENTROID_HPP | |
77 |