1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
|
// Boost.Geometry (aka GGL, Generic Geometry Library)
// Copyright (c) 2009-2012 Mateusz Loskot, London, UK.
// Copyright (c) 2009-2012 Barend Gehrels, Amsterdam, the Netherlands.
// Parts of Boost.Geometry are redesigned from Geodan's Geographic Library
// (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands.
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
#define BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
#include <boost/geometry/algorithms/detail/distance/interface.hpp>
#include <boost/geometry/algorithms/detail/distance/point_to_geometry.hpp>
#include <boost/geometry/arithmetic/arithmetic.hpp>
#include <boost/geometry/util/select_most_precise.hpp>
#include <boost/geometry/strategies/centroid.hpp>
#include <boost/geometry/strategies/default_distance_result.hpp>
// Helper geometry
#include <boost/geometry/geometries/point.hpp>
namespace boost { namespace geometry
{
namespace strategy { namespace centroid
{
namespace detail
{
template <typename Type, std::size_t DimensionCount>
struct weighted_length_sums
{
typedef typename geometry::model::point
<
Type, DimensionCount,
cs::cartesian
> work_point;
Type length;
work_point average_sum;
inline weighted_length_sums()
: length(Type())
{
geometry::assign_zero(average_sum);
}
};
}
template
<
typename Point,
typename PointOfSegment = Point
>
class weighted_length
{
private :
typedef typename select_most_precise
<
typename default_distance_result<Point>::type,
typename default_distance_result<PointOfSegment>::type
>::type distance_type;
public :
typedef detail::weighted_length_sums
<
distance_type,
geometry::dimension<Point>::type::value
> state_type;
static inline void apply(PointOfSegment const& p1,
PointOfSegment const& p2, state_type& state)
{
distance_type const d = geometry::distance(p1, p2);
state.length += d;
typename state_type::work_point weighted_median;
geometry::assign_zero(weighted_median);
geometry::add_point(weighted_median, p1);
geometry::add_point(weighted_median, p2);
geometry::multiply_value(weighted_median, d/2);
geometry::add_point(state.average_sum, weighted_median);
}
static inline bool result(state_type const& state, Point& centroid)
{
distance_type const zero = distance_type();
if (! geometry::math::equals(state.length, zero))
{
assign_zero(centroid);
add_point(centroid, state.average_sum);
divide_value(centroid, state.length);
return true;
}
return false;
}
};
#ifndef DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
namespace services
{
// Register this strategy for linear geometries, in all dimensions
template <std::size_t N, typename Point, typename Geometry>
struct default_strategy
<
cartesian_tag,
linear_tag,
N,
Point,
Geometry
>
{
typedef weighted_length
<
Point,
typename point_type<Geometry>::type
> type;
};
} // namespace services
#endif // DOXYGEN_NO_STRATEGY_SPECIALIZATIONS
}} // namespace strategy::centroid
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_STRATEGIES_CARTESIAN_CENTROID_WEIGHTED_LENGTH_HPP
|
