1 // Boost.Geometry (aka GGL, Generic Geometry Library)
2
3 // Copyright (c) 2007-2012 Barend Gehrels, Amsterdam, the Netherlands.
4
5 // This file was modified by Oracle on 2014, 2017.
6 // Modifications copyright (c) 2014-2017 Oracle and/or its affiliates.
7
8 // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
9
10 // Use, modification and distribution is subject to the Boost Software License,
11 // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
12 // http://www.boost.org/LICENSE_1_0.txt)
13
14 #ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_APPEND_NO_DUPS_OR_SPIKES_HPP
15 #define BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_APPEND_NO_DUPS_OR_SPIKES_HPP
16
17 #include <boost/range.hpp>
18
19 #include <boost/geometry/algorithms/append.hpp>
20 #include <boost/geometry/algorithms/detail/point_is_spike_or_equal.hpp>
21 #include <boost/geometry/algorithms/detail/equals/point_point.hpp>
22
23 #include <boost/geometry/util/condition.hpp>
24 #include <boost/geometry/util/range.hpp>
25
26
27 namespace boost { namespace geometry
28 {
29
30
31 #ifndef DOXYGEN_NO_DETAIL
32 namespace detail { namespace overlay
33 {
34
35 // TODO: move this / rename this
36 template <typename Point1, typename Point2, typename RobustPolicy>
points_equal_or_close(Point1 const & point1,Point2 const & point2,RobustPolicy const & robust_policy)37 inline bool points_equal_or_close(Point1 const& point1,
38 Point2 const& point2,
39 RobustPolicy const& robust_policy)
40 {
41 if (detail::equals::equals_point_point(point1, point2))
42 {
43 return true;
44 }
45
46 if (BOOST_GEOMETRY_CONDITION(! RobustPolicy::enabled))
47 {
48 return false;
49 }
50
51 // Try using specified robust policy
52 typedef typename geometry::robust_point_type
53 <
54 Point1,
55 RobustPolicy
56 >::type robust_point_type;
57
58 robust_point_type point1_rob, point2_rob;
59 geometry::recalculate(point1_rob, point1, robust_policy);
60 geometry::recalculate(point2_rob, point2, robust_policy);
61
62 return detail::equals::equals_point_point(point1_rob, point2_rob);
63 }
64
65
66 template <typename Range, typename Point, typename SideStrategy, typename RobustPolicy>
append_no_dups_or_spikes(Range & range,Point const & point,SideStrategy const & strategy,RobustPolicy const & robust_policy)67 inline void append_no_dups_or_spikes(Range& range, Point const& point,
68 SideStrategy const& strategy,
69 RobustPolicy const& robust_policy)
70 {
71 #ifdef BOOST_GEOMETRY_DEBUG_INTERSECTION
72 std::cout << " add: ("
73 << geometry::get<0>(point) << ", " << geometry::get<1>(point) << ")"
74 << std::endl;
75 #endif
76 // The code below this condition checks all spikes/dups
77 // for geometries >= 3 points.
78 // So we have to check the first potential duplicate differently
79 if (boost::size(range) == 1
80 && points_equal_or_close(*(boost::begin(range)), point, robust_policy))
81 {
82 return;
83 }
84
85 traits::push_back<Range>::apply(range, point);
86
87 // If a point is equal, or forming a spike, remove the pen-ultimate point
88 // because this one caused the spike.
89 // If so, the now-new-pen-ultimate point can again cause a spike
90 // (possibly at a corner). So keep doing this.
91 // Besides spikes it will also avoid adding duplicates.
92 while(boost::size(range) >= 3
93 && point_is_spike_or_equal(point,
94 *(boost::end(range) - 3),
95 *(boost::end(range) - 2),
96 strategy,
97 robust_policy))
98 {
99 // Use the Concept/traits, so resize and append again
100 traits::resize<Range>::apply(range, boost::size(range) - 2);
101 traits::push_back<Range>::apply(range, point);
102 }
103 }
104
105 template <typename Range, typename SideStrategy, typename RobustPolicy>
clean_closing_dups_and_spikes(Range & range,SideStrategy const & strategy,RobustPolicy const & robust_policy)106 inline void clean_closing_dups_and_spikes(Range& range,
107 SideStrategy const& strategy,
108 RobustPolicy const& robust_policy)
109 {
110 std::size_t const minsize
111 = core_detail::closure::minimum_ring_size
112 <
113 geometry::closure<Range>::value
114 >::value;
115
116 if (boost::size(range) <= minsize)
117 {
118 return;
119 }
120
121 typedef typename boost::range_iterator<Range>::type iterator_type;
122 static bool const closed = geometry::closure<Range>::value == geometry::closed;
123
124 // TODO: the following algorithm could be rewritten to first look for spikes
125 // and then erase some number of points from the beginning of the Range
126
127 bool found = false;
128 do
129 {
130 found = false;
131 iterator_type first = boost::begin(range);
132 iterator_type second = first + 1;
133 iterator_type ultimate = boost::end(range) - 1;
134 if (BOOST_GEOMETRY_CONDITION(closed))
135 {
136 ultimate--;
137 }
138
139 // Check if closing point is a spike (this is so if the second point is
140 // considered as a spike w.r.t. the last segment)
141 if (point_is_spike_or_equal(*second, *ultimate, *first, strategy, robust_policy))
142 {
143 range::erase(range, first);
144 if (BOOST_GEOMETRY_CONDITION(closed))
145 {
146 // Remove closing last point
147 range::resize(range, boost::size(range) - 1);
148 // Add new closing point
149 range::push_back(range, range::front(range));
150 }
151 found = true;
152 }
153 } while(found && boost::size(range) > minsize);
154 }
155
156
157 }} // namespace detail::overlay
158 #endif // DOXYGEN_NO_DETAIL
159
160
161 }} // namespace boost::geometry
162
163
164 #endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_OVERLAY_APPEND_NO_DUPS_OR_SPIKES_HPP
165