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1 | // Boost.Geometry (aka GGL, Generic Geometry Library) |
2 | ||
3 | // Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands. | |
4 | // Copyright (c) 2008-2015 Bruno Lalande, Paris, France. | |
5 | // Copyright (c) 2009-2015 Mateusz Loskot, London, UK. | |
6 | ||
7 | // This file was modified by Oracle on 2014, 2015. | |
8 | // Modifications copyright (c) 2014-2015 Oracle and/or its affiliates. | |
9 | ||
10 | // Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle | |
11 | // Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle | |
12 | ||
13 | // Parts of Boost.Geometry are redesigned from Geodan's Geographic Library | |
14 | // (geolib/GGL), copyright (c) 1995-2010 Geodan, Amsterdam, the Netherlands. | |
15 | ||
16 | // Use, modification and distribution is subject to the Boost Software License, | |
17 | // Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
18 | // http://www.boost.org/LICENSE_1_0.txt) | |
19 | ||
20 | #ifndef BOOST_GEOMETRY_ALGORITHMS_CONVEX_HULL_HPP | |
21 | #define BOOST_GEOMETRY_ALGORITHMS_CONVEX_HULL_HPP | |
22 | ||
23 | #include <boost/array.hpp> | |
24 | ||
25 | #include <boost/variant/apply_visitor.hpp> | |
26 | #include <boost/variant/static_visitor.hpp> | |
27 | #include <boost/variant/variant_fwd.hpp> | |
28 | ||
29 | #include <boost/geometry/core/cs.hpp> | |
30 | #include <boost/geometry/core/point_order.hpp> | |
31 | #include <boost/geometry/core/closure.hpp> | |
32 | #include <boost/geometry/core/exterior_ring.hpp> | |
33 | ||
34 | #include <boost/geometry/geometries/concepts/check.hpp> | |
35 | ||
36 | #include <boost/geometry/strategies/convex_hull.hpp> | |
37 | #include <boost/geometry/strategies/concepts/convex_hull_concept.hpp> | |
38 | #include <boost/geometry/strategies/default_strategy.hpp> | |
39 | ||
40 | #include <boost/geometry/util/condition.hpp> | |
41 | ||
42 | #include <boost/geometry/views/detail/range_type.hpp> | |
43 | ||
44 | #include <boost/geometry/algorithms/is_empty.hpp> | |
45 | #include <boost/geometry/algorithms/detail/as_range.hpp> | |
46 | #include <boost/geometry/algorithms/detail/assign_box_corners.hpp> | |
47 | ||
48 | ||
49 | namespace boost { namespace geometry | |
50 | { | |
51 | ||
52 | ||
53 | #ifndef DOXYGEN_NO_DETAIL | |
54 | namespace detail { namespace convex_hull | |
55 | { | |
56 | ||
57 | template <order_selector Order, closure_selector Closure> | |
58 | struct hull_insert | |
59 | { | |
60 | ||
61 | // Member template function (to avoid inconvenient declaration | |
62 | // of output-iterator-type, from hull_to_geometry) | |
63 | template <typename Geometry, typename OutputIterator, typename Strategy> | |
64 | static inline OutputIterator apply(Geometry const& geometry, | |
65 | OutputIterator out, Strategy const& strategy) | |
66 | { | |
67 | typename Strategy::state_type state; | |
68 | ||
69 | strategy.apply(geometry, state); | |
70 | strategy.result(state, out, Order == clockwise, Closure != open); | |
71 | return out; | |
72 | } | |
73 | }; | |
74 | ||
75 | struct hull_to_geometry | |
76 | { | |
77 | template <typename Geometry, typename OutputGeometry, typename Strategy> | |
78 | static inline void apply(Geometry const& geometry, OutputGeometry& out, | |
79 | Strategy const& strategy) | |
80 | { | |
81 | hull_insert | |
82 | < | |
83 | geometry::point_order<OutputGeometry>::value, | |
84 | geometry::closure<OutputGeometry>::value | |
85 | >::apply(geometry, | |
86 | range::back_inserter( | |
87 | // Handle linestring, ring and polygon the same: | |
88 | detail::as_range | |
89 | < | |
90 | typename range_type<OutputGeometry>::type | |
91 | >(out)), strategy); | |
92 | } | |
93 | }; | |
94 | ||
95 | }} // namespace detail::convex_hull | |
96 | #endif // DOXYGEN_NO_DETAIL | |
97 | ||
98 | ||
99 | #ifndef DOXYGEN_NO_DISPATCH | |
100 | namespace dispatch | |
101 | { | |
102 | ||
103 | ||
104 | template | |
105 | < | |
106 | typename Geometry, | |
107 | typename Tag = typename tag<Geometry>::type | |
108 | > | |
109 | struct convex_hull | |
110 | : detail::convex_hull::hull_to_geometry | |
111 | {}; | |
112 | ||
113 | template <typename Box> | |
114 | struct convex_hull<Box, box_tag> | |
115 | { | |
116 | template <typename OutputGeometry, typename Strategy> | |
117 | static inline void apply(Box const& box, OutputGeometry& out, | |
118 | Strategy const& ) | |
119 | { | |
120 | static bool const Close | |
121 | = geometry::closure<OutputGeometry>::value == closed; | |
122 | static bool const Reverse | |
123 | = geometry::point_order<OutputGeometry>::value == counterclockwise; | |
124 | ||
125 | // A hull for boxes is trivial. Any strategy is (currently) skipped. | |
126 | boost::array<typename point_type<Box>::type, 4> range; | |
127 | geometry::detail::assign_box_corners_oriented<Reverse>(box, range); | |
128 | geometry::append(out, range); | |
129 | if (BOOST_GEOMETRY_CONDITION(Close)) | |
130 | { | |
131 | geometry::append(out, *boost::begin(range)); | |
132 | } | |
133 | } | |
134 | }; | |
135 | ||
136 | ||
137 | ||
138 | template <order_selector Order, closure_selector Closure> | |
139 | struct convex_hull_insert | |
140 | : detail::convex_hull::hull_insert<Order, Closure> | |
141 | {}; | |
142 | ||
143 | ||
144 | } // namespace dispatch | |
145 | #endif // DOXYGEN_NO_DISPATCH | |
146 | ||
147 | ||
148 | namespace resolve_strategy { | |
149 | ||
150 | struct convex_hull | |
151 | { | |
152 | template <typename Geometry, typename OutputGeometry, typename Strategy> | |
153 | static inline void apply(Geometry const& geometry, | |
154 | OutputGeometry& out, | |
155 | Strategy const& strategy) | |
156 | { | |
157 | BOOST_CONCEPT_ASSERT( (geometry::concepts::ConvexHullStrategy<Strategy>) ); | |
158 | dispatch::convex_hull<Geometry>::apply(geometry, out, strategy); | |
159 | } | |
160 | ||
161 | template <typename Geometry, typename OutputGeometry> | |
162 | static inline void apply(Geometry const& geometry, | |
163 | OutputGeometry& out, | |
164 | default_strategy) | |
165 | { | |
166 | typedef typename strategy_convex_hull< | |
167 | Geometry, | |
168 | typename point_type<Geometry>::type | |
169 | >::type strategy_type; | |
170 | ||
171 | apply(geometry, out, strategy_type()); | |
172 | } | |
173 | }; | |
174 | ||
175 | struct convex_hull_insert | |
176 | { | |
177 | template <typename Geometry, typename OutputIterator, typename Strategy> | |
178 | static inline OutputIterator apply(Geometry const& geometry, | |
179 | OutputIterator& out, | |
180 | Strategy const& strategy) | |
181 | { | |
182 | BOOST_CONCEPT_ASSERT( (geometry::concepts::ConvexHullStrategy<Strategy>) ); | |
183 | ||
184 | return dispatch::convex_hull_insert< | |
185 | geometry::point_order<Geometry>::value, | |
186 | geometry::closure<Geometry>::value | |
187 | >::apply(geometry, out, strategy); | |
188 | } | |
189 | ||
190 | template <typename Geometry, typename OutputIterator> | |
191 | static inline OutputIterator apply(Geometry const& geometry, | |
192 | OutputIterator& out, | |
193 | default_strategy) | |
194 | { | |
195 | typedef typename strategy_convex_hull< | |
196 | Geometry, | |
197 | typename point_type<Geometry>::type | |
198 | >::type strategy_type; | |
199 | ||
200 | return apply(geometry, out, strategy_type()); | |
201 | } | |
202 | }; | |
203 | ||
204 | } // namespace resolve_strategy | |
205 | ||
206 | ||
207 | namespace resolve_variant { | |
208 | ||
209 | template <typename Geometry> | |
210 | struct convex_hull | |
211 | { | |
212 | template <typename OutputGeometry, typename Strategy> | |
213 | static inline void apply(Geometry const& geometry, OutputGeometry& out, Strategy const& strategy) | |
214 | { | |
215 | concepts::check_concepts_and_equal_dimensions< | |
216 | const Geometry, | |
217 | OutputGeometry | |
218 | >(); | |
219 | ||
220 | resolve_strategy::convex_hull::apply(geometry, out, strategy); | |
221 | } | |
222 | }; | |
223 | ||
224 | template <BOOST_VARIANT_ENUM_PARAMS(typename T)> | |
225 | struct convex_hull<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> > | |
226 | { | |
227 | template <typename OutputGeometry, typename Strategy> | |
228 | struct visitor: boost::static_visitor<void> | |
229 | { | |
230 | OutputGeometry& m_out; | |
231 | Strategy const& m_strategy; | |
232 | ||
233 | visitor(OutputGeometry& out, Strategy const& strategy) | |
234 | : m_out(out), m_strategy(strategy) | |
235 | {} | |
236 | ||
237 | template <typename Geometry> | |
238 | void operator()(Geometry const& geometry) const | |
239 | { | |
240 | convex_hull<Geometry>::apply(geometry, m_out, m_strategy); | |
241 | } | |
242 | }; | |
243 | ||
244 | template <typename OutputGeometry, typename Strategy> | |
245 | static inline void | |
246 | apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry, | |
247 | OutputGeometry& out, | |
248 | Strategy const& strategy) | |
249 | { | |
250 | boost::apply_visitor(visitor<OutputGeometry, Strategy>(out, strategy), geometry); | |
251 | } | |
252 | }; | |
253 | ||
254 | template <typename Geometry> | |
255 | struct convex_hull_insert | |
256 | { | |
257 | template <typename OutputIterator, typename Strategy> | |
258 | static inline OutputIterator apply(Geometry const& geometry, OutputIterator& out, Strategy const& strategy) | |
259 | { | |
260 | // Concept: output point type = point type of input geometry | |
261 | concepts::check<Geometry const>(); | |
262 | concepts::check<typename point_type<Geometry>::type>(); | |
263 | ||
264 | return resolve_strategy::convex_hull_insert::apply(geometry, out, strategy); | |
265 | } | |
266 | }; | |
267 | ||
268 | template <BOOST_VARIANT_ENUM_PARAMS(typename T)> | |
269 | struct convex_hull_insert<boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> > | |
270 | { | |
271 | template <typename OutputIterator, typename Strategy> | |
272 | struct visitor: boost::static_visitor<OutputIterator> | |
273 | { | |
274 | OutputIterator& m_out; | |
275 | Strategy const& m_strategy; | |
276 | ||
277 | visitor(OutputIterator& out, Strategy const& strategy) | |
278 | : m_out(out), m_strategy(strategy) | |
279 | {} | |
280 | ||
281 | template <typename Geometry> | |
282 | OutputIterator operator()(Geometry const& geometry) const | |
283 | { | |
284 | return convex_hull_insert<Geometry>::apply(geometry, m_out, m_strategy); | |
285 | } | |
286 | }; | |
287 | ||
288 | template <typename OutputIterator, typename Strategy> | |
289 | static inline OutputIterator | |
290 | apply(boost::variant<BOOST_VARIANT_ENUM_PARAMS(T)> const& geometry, | |
291 | OutputIterator& out, | |
292 | Strategy const& strategy) | |
293 | { | |
294 | return boost::apply_visitor(visitor<OutputIterator, Strategy>(out, strategy), geometry); | |
295 | } | |
296 | }; | |
297 | ||
298 | } // namespace resolve_variant | |
299 | ||
300 | ||
301 | template<typename Geometry, typename OutputGeometry, typename Strategy> | |
302 | inline void convex_hull(Geometry const& geometry, | |
303 | OutputGeometry& out, Strategy const& strategy) | |
304 | { | |
305 | if (geometry::is_empty(geometry)) | |
306 | { | |
307 | // Leave output empty | |
308 | return; | |
309 | } | |
310 | ||
311 | resolve_variant::convex_hull<Geometry>::apply(geometry, out, strategy); | |
312 | } | |
313 | ||
314 | ||
315 | /*! | |
316 | \brief \brief_calc{convex hull} | |
317 | \ingroup convex_hull | |
318 | \details \details_calc{convex_hull,convex hull}. | |
319 | \tparam Geometry the input geometry type | |
320 | \tparam OutputGeometry the output geometry type | |
321 | \param geometry \param_geometry, input geometry | |
322 | \param hull \param_geometry \param_set{convex hull} | |
323 | ||
324 | \qbk{[include reference/algorithms/convex_hull.qbk]} | |
325 | */ | |
326 | template<typename Geometry, typename OutputGeometry> | |
327 | inline void convex_hull(Geometry const& geometry, | |
328 | OutputGeometry& hull) | |
329 | { | |
330 | geometry::convex_hull(geometry, hull, default_strategy()); | |
331 | } | |
332 | ||
333 | #ifndef DOXYGEN_NO_DETAIL | |
334 | namespace detail { namespace convex_hull | |
335 | { | |
336 | ||
337 | ||
338 | template<typename Geometry, typename OutputIterator, typename Strategy> | |
339 | inline OutputIterator convex_hull_insert(Geometry const& geometry, | |
340 | OutputIterator out, Strategy const& strategy) | |
341 | { | |
342 | return resolve_variant::convex_hull_insert<Geometry> | |
343 | ::apply(geometry, out, strategy); | |
344 | } | |
345 | ||
346 | ||
347 | /*! | |
348 | \brief Calculate the convex hull of a geometry, output-iterator version | |
349 | \ingroup convex_hull | |
350 | \tparam Geometry the input geometry type | |
351 | \tparam OutputIterator: an output-iterator | |
352 | \param geometry the geometry to calculate convex hull from | |
353 | \param out an output iterator outputing points of the convex hull | |
354 | \note This overloaded version outputs to an output iterator. | |
355 | In this case, nothing is known about its point-type or | |
356 | about its clockwise order. Therefore, the input point-type | |
357 | and order are copied | |
358 | ||
359 | */ | |
360 | template<typename Geometry, typename OutputIterator> | |
361 | inline OutputIterator convex_hull_insert(Geometry const& geometry, | |
362 | OutputIterator out) | |
363 | { | |
364 | return convex_hull_insert(geometry, out, default_strategy()); | |
365 | } | |
366 | ||
367 | ||
368 | }} // namespace detail::convex_hull | |
369 | #endif // DOXYGEN_NO_DETAIL | |
370 | ||
371 | ||
372 | }} // namespace boost::geometry | |
373 | ||
374 | ||
375 | #endif // BOOST_GEOMETRY_ALGORITHMS_CONVEX_HULL_HPP |