detail/algorithms/comparable_distance_centroid.hpp

0001 // Boost.Geometry Index
0002 //
0003 // squared distance between point and centroid of the box or point
0004 //
0005 // Copyright (c) 2011-2014 Adam Wulkiewicz, Lodz, Poland.
0006 //
0007 // This file was modified by Oracle on 2021.
0008 // Modifications copyright (c) 2021 Oracle and/or its affiliates.
0009 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
0010 //
0011 // Use, modification and distribution is subject to the Boost Software License,
0012 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
0013 // http://www.boost.org/LICENSE_1_0.txt)
0014
0015 #ifndef BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_COMPARABLE_DISTANCE_CENTROID_HPP
0016 #define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_COMPARABLE_DISTANCE_CENTROID_HPP
0017
0018 #include <boost/geometry/algorithms/detail/comparable_distance/interface.hpp>
0019 #include <boost/geometry/core/access.hpp>
0020
0021 #include <boost/geometry/index/detail/algorithms/sum_for_indexable.hpp>
0022 #include <boost/geometry/index/detail/algorithms/diff_abs.hpp>
0023
0024 namespace boost { namespace geometry { namespace index { namespace detail {
0025
0026 struct comparable_distance_centroid_tag {};
0027
0028 template <
0029     typename Point,
0030     typename PointIndexable,
0031     size_t N>
0032 struct sum_for_indexable<Point, PointIndexable, point_tag, comparable_distance_centroid_tag, N>
0033 {
0034     typedef typename geometry::default_comparable_distance_result<Point, PointIndexable>::type result_type;
0035
0036     inline static result_type apply(Point const& pt, PointIndexable const& i)
0037     {
0038         return geometry::comparable_distance(pt, i);
0039     }
0040 };
0041
0042 template <
0043     typename Point,
0044     typename BoxIndexable,
0045     size_t DimensionIndex>
0046 struct sum_for_indexable_dimension<Point, BoxIndexable, box_tag, comparable_distance_centroid_tag, DimensionIndex>
0047 {
0048     typedef typename geometry::default_comparable_distance_result<Point, BoxIndexable>::type result_type;
0049
0050     inline static result_type apply(Point const& pt, BoxIndexable const& i)
0051     {
0052         typedef typename coordinate_type<Point>::type point_coord_t;
0053         typedef typename coordinate_type<BoxIndexable>::type indexable_coord_t;
0054
0055         point_coord_t pt_c = geometry::get<DimensionIndex>(pt);
0056         indexable_coord_t ind_c_min = geometry::get<geometry::min_corner, DimensionIndex>(i);
0057         indexable_coord_t ind_c_max = geometry::get<geometry::max_corner, DimensionIndex>(i);
0058
0059         indexable_coord_t ind_c_avg = ind_c_min + (ind_c_max - ind_c_min) / 2;
0060         // TODO: awulkiew - is (ind_c_min + ind_c_max) / 2 safe?
0061
0062         result_type diff = detail::diff_abs(ind_c_avg, pt_c);
0063
0064         return diff * diff;
0065     }
0066 };
0067
0068 template <typename Point, typename Indexable>
0069 typename geometry::default_comparable_distance_result<Point, Indexable>::type
0070 comparable_distance_centroid(Point const& pt, Indexable const& i)
0071 {
0072     return detail::sum_for_indexable<
0073         Point,
0074         Indexable,
0075         typename tag<Indexable>::type,
0076         detail::comparable_distance_centroid_tag,
0077         dimension<Indexable>::value
0078     >::apply(pt, i);
0079 }
0080
0081 }}}} // namespace boost::geometry::index::detail
0082
0083 #endif // #define BOOST_GEOMETRY_INDEX_DETAIL_ALGORITHMS_COMPARABLE_DISTANCE_CENTROID_HPP
0084