libs/geometry/doc/html/geometry/reference/algorithms/reverse.html

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  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="idp103981792"></a>
  31 Reverses 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">&lt;</span><span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">&gt;</span>
  49 <span class="keyword">void</span> <span class="identifier">reverse</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="special">&amp;</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 &amp;
  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">&lt;</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">&gt;</span></code>
 117         </p>
 118 <p>
 119           Or
 120         </p>
 121 <p>
 122           <code class="computeroutput"><span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</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">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 293
 294 <span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</span>
 295 <span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</span>
 296 <span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</span>
 297 <span class="preprocessor">#include</span> <span class="special">&lt;</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">&gt;</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">&lt;</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">&gt;</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">&lt;</span><span class="keyword">int</span><span class="special">,</span> <span class="keyword">int</span><span class="special">&gt;</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">&lt;</span><span class="identifier">point</span><span class="special">&gt;</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">&lt;</span><span class="identifier">point</span><span class="special">&gt;</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">&lt;&lt;</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">&lt;&lt;</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">&lt;&lt;</span> <span class="identifier">area_before</span> <span class="special">&lt;&lt;</span> <span class="string">" -&gt; "</span> <span class="special">&lt;&lt;</span> <span class="identifier">area_after</span> <span class="special">&lt;&lt;</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">&lt;&lt;</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">&lt;&lt;</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">&lt;&lt;</span> <span class="identifier">area_before</span> <span class="special">&lt;&lt;</span> <span class="string">" -&gt; "</span> <span class="special">&lt;&lt;</span> <span class="identifier">area_after</span> <span class="special">&lt;&lt;</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)))
 339 38 -&gt; -38
 340 ((0, 0), (8, 8), (0, 9), (0, 0))
 341 36 -&gt; -36
 342 </pre>
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