1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>reverse</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Chapter 1. Geometry"> 8<link rel="up" href="../algorithms.html" title="Algorithms"> 9<link rel="prev" href="relation/relation_2.html" title="relation"> 10<link rel="next" href="simplify.html" title="simplify"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="relation/relation_2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../algorithms.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="simplify.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="geometry.reference.algorithms.reverse"></a><a class="link" href="reverse.html" title="reverse">reverse</a> 28</h4></div></div></div> 29<p> 30 <a class="indexterm" name="idm45635689483328"></a> 31Reverses the points within a geometry. 32 </p> 33<h6> 34<a name="geometry.reference.algorithms.reverse.h0"></a> 35 <span class="phrase"><a name="geometry.reference.algorithms.reverse.description"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.description">Description</a> 36 </h6> 37<p> 38 Generic function to reverse a geometry. It resembles the std::reverse functionality, 39 but it takes the geometry type into account. Only for a ring or for a linestring 40 it is the same as the std::reverse. 41 </p> 42<h6> 43<a name="geometry.reference.algorithms.reverse.h1"></a> 44 <span class="phrase"><a name="geometry.reference.algorithms.reverse.synopsis"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.synopsis">Synopsis</a> 45 </h6> 46<p> 47</p> 48<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">></span> 49<span class="keyword">void</span> <span class="identifier">reverse</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="special">&</span> <span class="identifier">geometry</span><span class="special">)</span></pre> 50<p> 51 </p> 52<h6> 53<a name="geometry.reference.algorithms.reverse.h2"></a> 54 <span class="phrase"><a name="geometry.reference.algorithms.reverse.parameters"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.parameters">Parameters</a> 55 </h6> 56<div class="informaltable"><table class="table"> 57<colgroup> 58<col> 59<col> 60<col> 61<col> 62</colgroup> 63<thead><tr> 64<th> 65 <p> 66 Type 67 </p> 68 </th> 69<th> 70 <p> 71 Concept 72 </p> 73 </th> 74<th> 75 <p> 76 Name 77 </p> 78 </th> 79<th> 80 <p> 81 Description 82 </p> 83 </th> 84</tr></thead> 85<tbody><tr> 86<td> 87 <p> 88 Geometry & 89 </p> 90 </td> 91<td> 92 <p> 93 Any type fulfilling a Geometry Concept 94 </p> 95 </td> 96<td> 97 <p> 98 geometry 99 </p> 100 </td> 101<td> 102 <p> 103 A model of the specified concept which will be reversed 104 </p> 105 </td> 106</tr></tbody> 107</table></div> 108<h6> 109<a name="geometry.reference.algorithms.reverse.h3"></a> 110 <span class="phrase"><a name="geometry.reference.algorithms.reverse.header"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.header">Header</a> 111 </h6> 112<p> 113 Either 114 </p> 115<p> 116 <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 117 </p> 118<p> 119 Or 120 </p> 121<p> 122 <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">algorithms</span><span class="special">/</span><span class="identifier">reverse</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 123 </p> 124<h6> 125<a name="geometry.reference.algorithms.reverse.h4"></a> 126 <span class="phrase"><a name="geometry.reference.algorithms.reverse.conformance"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.conformance">Conformance</a> 127 </h6> 128<p> 129 The function reverse is not defined by OGC. 130 </p> 131<p> 132 The function reverse conforms to the std::reverse function of the C++ std-library. 133 </p> 134<h6> 135<a name="geometry.reference.algorithms.reverse.h5"></a> 136 <span class="phrase"><a name="geometry.reference.algorithms.reverse.behavior"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.behavior">Behavior</a> 137 </h6> 138<div class="informaltable"><table class="table"> 139<colgroup> 140<col> 141<col> 142</colgroup> 143<thead><tr> 144<th> 145 <p> 146 Case 147 </p> 148 </th> 149<th> 150 <p> 151 Behavior 152 </p> 153 </th> 154</tr></thead> 155<tbody> 156<tr> 157<td> 158 <p> 159 Point 160 </p> 161 </td> 162<td> 163 <p> 164 Nothing happens, geometry is unchanged 165 </p> 166 </td> 167</tr> 168<tr> 169<td> 170 <p> 171 Segment 172 </p> 173 </td> 174<td> 175 <p> 176 Not yet supported in this version 177 </p> 178 </td> 179</tr> 180<tr> 181<td> 182 <p> 183 Box 184 </p> 185 </td> 186<td> 187 <p> 188 Nothing happens, geometry is unchanged 189 </p> 190 </td> 191</tr> 192<tr> 193<td> 194 <p> 195 Linestring 196 </p> 197 </td> 198<td> 199 <p> 200 Reverses the Linestring 201 </p> 202 </td> 203</tr> 204<tr> 205<td> 206 <p> 207 Ring 208 </p> 209 </td> 210<td> 211 <p> 212 Reverses the Ring 213 </p> 214 </td> 215</tr> 216<tr> 217<td> 218 <p> 219 Polygon 220 </p> 221 </td> 222<td> 223 <p> 224 Reverses the exterior ring and all interior rings in the polygon 225 </p> 226 </td> 227</tr> 228<tr> 229<td> 230 <p> 231 Multi Point 232 </p> 233 </td> 234<td> 235 <p> 236 Nothing happens, geometry is unchanged 237 </p> 238 </td> 239</tr> 240<tr> 241<td> 242 <p> 243 Multi Linestring 244 </p> 245 </td> 246<td> 247 <p> 248 Reverses all contained linestrings individually 249 </p> 250 </td> 251</tr> 252<tr> 253<td> 254 <p> 255 Multi Polygon 256 </p> 257 </td> 258<td> 259 <p> 260 Reverses all contained polygons individually 261 </p> 262 </td> 263</tr> 264</tbody> 265</table></div> 266<div class="note"><table border="0" summary="Note"> 267<tr> 268<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td> 269<th align="left">Note</th> 270</tr> 271<tr><td align="left" valign="top"><p> 272 The reverse of a (multi)polygon or ring might make a valid geometry invalid 273 because the (counter)clockwise orientation reverses. 274 </p></td></tr> 275</table></div> 276<h6> 277<a name="geometry.reference.algorithms.reverse.h6"></a> 278 <span class="phrase"><a name="geometry.reference.algorithms.reverse.complexity"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.complexity">Complexity</a> 279 </h6> 280<p> 281 Linear 282 </p> 283<h6> 284<a name="geometry.reference.algorithms.reverse.h7"></a> 285 <span class="phrase"><a name="geometry.reference.algorithms.reverse.example"></a></span><a class="link" href="reverse.html#geometry.reference.algorithms.reverse.example">Example</a> 286 </h6> 287<p> 288 Shows how to reverse a ring or polygon 289 </p> 290<p> 291</p> 292<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 293 294<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 295<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 296<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">ring</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 297<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">/</span><span class="identifier">adapted</span><span class="special">/</span><span class="identifier">boost_tuple</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 298 299<span class="identifier">BOOST_GEOMETRY_REGISTER_BOOST_TUPLE_CS</span><span class="special">(</span><span class="identifier">cs</span><span class="special">::</span><span class="identifier">cartesian</span><span class="special">)</span> 300 301<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">assign</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 302 303<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 304<span class="special">{</span> 305 <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">assign</span><span class="special">::</span><span class="identifier">tuple_list_of</span><span class="special">;</span> 306 307 <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">tuple</span><span class="special"><</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">></span> <span class="identifier">point</span><span class="special">;</span> 308 <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">polygon</span><span class="special"><</span><span class="identifier">point</span><span class="special">></span> <span class="identifier">polygon</span><span class="special">;</span> 309 <span class="keyword">typedef</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">model</span><span class="special">::</span><span class="identifier">ring</span><span class="special"><</span><span class="identifier">point</span><span class="special">></span> <span class="identifier">ring</span><span class="special">;</span> 310 311 312 <span class="identifier">polygon</span> <span class="identifier">poly</span><span class="special">;</span> 313 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">exterior_ring</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special">=</span> <span class="identifier">tuple_list_of</span><span class="special">(</span><span class="number">0</span><span class="special">,</span> <span class="number">0</span><span class="special">)(</span><span class="number">0</span><span class="special">,</span> <span class="number">9</span><span class="special">)(</span><span class="number">10</span><span class="special">,</span> <span class="number">10</span><span class="special">)(</span><span class="number">0</span><span class="special">,</span> <span class="number">0</span><span class="special">);</span> 314 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">interior_rings</span><span class="special">(</span><span class="identifier">poly</span><span class="special">).</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">tuple_list_of</span><span class="special">(</span><span class="number">1</span><span class="special">,</span> <span class="number">2</span><span class="special">)(</span><span class="number">4</span><span class="special">,</span> <span class="number">6</span><span class="special">)(</span><span class="number">2</span><span class="special">,</span> <span class="number">8</span><span class="special">)(</span><span class="number">1</span><span class="special">,</span> <span class="number">2</span><span class="special">));</span> 315 316 <span class="keyword">double</span> <span class="identifier">area_before</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">area</span><span class="special">(</span><span class="identifier">poly</span><span class="special">);</span> 317 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">reverse</span><span class="special">(</span><span class="identifier">poly</span><span class="special">);</span> 318 <span class="keyword">double</span> <span class="identifier">area_after</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">area</span><span class="special">(</span><span class="identifier">poly</span><span class="special">);</span> 319 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">dsv</span><span class="special">(</span><span class="identifier">poly</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 320 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">area_before</span> <span class="special"><<</span> <span class="string">" -> "</span> <span class="special"><<</span> <span class="identifier">area_after</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 321 322 <span class="identifier">ring</span> <span class="identifier">r</span> <span class="special">=</span> <span class="identifier">tuple_list_of</span><span class="special">(</span><span class="number">0</span><span class="special">,</span> <span class="number">0</span><span class="special">)(</span><span class="number">0</span><span class="special">,</span> <span class="number">9</span><span class="special">)(</span><span class="number">8</span><span class="special">,</span> <span class="number">8</span><span class="special">)(</span><span class="number">0</span><span class="special">,</span> <span class="number">0</span><span class="special">);</span> 323 324 <span class="identifier">area_before</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">area</span><span class="special">(</span><span class="identifier">r</span><span class="special">);</span> 325 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">reverse</span><span class="special">(</span><span class="identifier">r</span><span class="special">);</span> 326 <span class="identifier">area_after</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">area</span><span class="special">(</span><span class="identifier">r</span><span class="special">);</span> 327 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">dsv</span><span class="special">(</span><span class="identifier">r</span><span class="special">)</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 328 <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">area_before</span> <span class="special"><<</span> <span class="string">" -> "</span> <span class="special"><<</span> <span class="identifier">area_after</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> 329 330 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 331<span class="special">}</span> 332</pre> 333<p> 334 </p> 335<p> 336 Output: 337 </p> 338<pre class="programlisting">(((0, 0), (10, 10), (0, 9), (0, 0)), ((1, 2), (2, 8), (4, 6), (1, 2))) 33938 -> -38 340((0, 0), (8, 8), (0, 9), (0, 0)) 34136 -> -36 342</pre> 343</div> 344<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 345<td align="left"></td> 346<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 347 Wulkiewicz, Oracle and/or its affiliates<p> 348 Distributed under the Boost Software License, Version 1.0. (See accompanying 349 file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) 350 </p> 351</div></td> 352</tr></table> 353<hr> 354<div class="spirit-nav"> 355<a accesskey="p" href="relation/relation_2.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../algorithms.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="simplify.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 356</div> 357</body> 358</html> 359
