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

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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="geometry.reference.algorithms.num_segments"></a><a class="link" href="num_segments.html" title="num_segments">num_segments</a>
  28 </h4></div></div></div>
  29 <p>
  30           <a class="indexterm" name="idp102287184"></a>
  31 Calculates the number of segments of a geometry.
  32         </p>
  33 <h6>
  34 <a name="geometry.reference.algorithms.num_segments.h0"></a>
  35           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.description"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.description">Description</a>
  36         </h6>
  37 <p>
  38           The free function num_segments calculates the number of segments of a geometry.
  39         </p>
  40 <h6>
  41 <a name="geometry.reference.algorithms.num_segments.h1"></a>
  42           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.synopsis"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.synopsis">Synopsis</a>
  43         </h6>
  44 <p>
  45 </p>
  46 <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>
  47 <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">num_segments</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">geometry</span><span class="special">)</span></pre>
  48 <p>
  49         </p>
  50 <h6>
  51 <a name="geometry.reference.algorithms.num_segments.h2"></a>
  52           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.parameters"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.parameters">Parameters</a>
  53         </h6>
  54 <div class="informaltable"><table class="table">
  55 <colgroup>
  56 <col>
  57 <col>
  58 <col>
  59 <col>
  60 </colgroup>
  61 <thead><tr>
  62 <th>
  63                   <p>
  64                     Type
  65                   </p>
  66                 </th>
  67 <th>
  68                   <p>
  69                     Concept
  70                   </p>
  71                 </th>
  72 <th>
  73                   <p>
  74                     Name
  75                   </p>
  76                 </th>
  77 <th>
  78                   <p>
  79                     Description
  80                   </p>
  81                 </th>
  82 </tr></thead>
  83 <tbody><tr>
  84 <td>
  85                   <p>
  86                     Geometry const &amp;
  87                   </p>
  88                 </td>
  89 <td>
  90                   <p>
  91                     Any type fulfilling a Geometry Concept
  92                   </p>
  93                 </td>
  94 <td>
  95                   <p>
  96                     geometry
  97                   </p>
  98                 </td>
  99 <td>
 100                   <p>
 101                     A model of the specified concept
 102                   </p>
 103                 </td>
 104 </tr></tbody>
 105 </table></div>
 106 <h6>
 107 <a name="geometry.reference.algorithms.num_segments.h3"></a>
 108           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.returns"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.returns">Returns</a>
 109         </h6>
 110 <p>
 111           The calculated number of segments
 112         </p>
 113 <h6>
 114 <a name="geometry.reference.algorithms.num_segments.h4"></a>
 115           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.header"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.header">Header</a>
 116         </h6>
 117 <p>
 118           Either
 119         </p>
 120 <p>
 121           <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>
 122         </p>
 123 <p>
 124           Or
 125         </p>
 126 <p>
 127           <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">num_segments</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 128         </p>
 129 <h6>
 130 <a name="geometry.reference.algorithms.num_segments.h5"></a>
 131           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.conformance"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.conformance">Conformance</a>
 132         </h6>
 133 <p>
 134           The function num_segments is not defined by OGC.
 135         </p>
 136 <h6>
 137 <a name="geometry.reference.algorithms.num_segments.h6"></a>
 138           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.behavior"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.behavior">Behavior</a>
 139         </h6>
 140 <div class="informaltable"><table class="table">
 141 <colgroup>
 142 <col>
 143 <col>
 144 </colgroup>
 145 <thead><tr>
 146 <th>
 147                   <p>
 148                     Case
 149                   </p>
 150                 </th>
 151 <th>
 152                   <p>
 153                     Behavior
 154                   </p>
 155                 </th>
 156 </tr></thead>
 157 <tbody>
 158 <tr>
 159 <td>
 160                   <p>
 161                     pointlike (e.g. point)
 162                   </p>
 163                 </td>
 164 <td>
 165                   <p>
 166                     Returns 0
 167                   </p>
 168                 </td>
 169 </tr>
 170 <tr>
 171 <td>
 172                   <p>
 173                     Segment
 174                   </p>
 175                 </td>
 176 <td>
 177                   <p>
 178                     Returns 1
 179                   </p>
 180                 </td>
 181 </tr>
 182 <tr>
 183 <td>
 184                   <p>
 185                     Box
 186                   </p>
 187                 </td>
 188 <td>
 189                   <p>
 190                     Returns d * 2^(d-1), where d is the dimension of the box
 191                   </p>
 192                 </td>
 193 </tr>
 194 <tr>
 195 <td>
 196                   <p>
 197                     Rangelike (linestring, ring)
 198                   </p>
 199                 </td>
 200 <td>
 201                   <p>
 202                     Returns boost::size(geometry) - 1
 203                   </p>
 204                 </td>
 205 </tr>
 206 <tr>
 207 <td>
 208                   <p>
 209                     Other geometries
 210                   </p>
 211                 </td>
 212 <td>
 213                   <p>
 214                     Returns the sum of the number of segments of its elements
 215                   </p>
 216                 </td>
 217 </tr>
 218 </tbody>
 219 </table></div>
 220 <h6>
 221 <a name="geometry.reference.algorithms.num_segments.h7"></a>
 222           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.complexity"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.complexity">Complexity</a>
 223         </h6>
 224 <p>
 225           Constant or Linear
 226         </p>
 227 <h6>
 228 <a name="geometry.reference.algorithms.num_segments.h8"></a>
 229           <span class="phrase"><a name="geometry.reference.algorithms.num_segments.examples"></a></span><a class="link" href="num_segments.html#geometry.reference.algorithms.num_segments.examples">Examples</a>
 230         </h6>
 231 <p>
 232           Get the number of segments in a geometry
 233         </p>
 234 <p>
 235 </p>
 236 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 237
 238 <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>
 239 <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">point_xy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
 240
 241
 242 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 243 <span class="special">{</span>
 244     <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">multi_polygon</span>
 245         <span class="special">&lt;</span>
 246             <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>
 247                 <span class="special">&lt;</span>
 248                     <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">d2</span><span class="special">::</span><span class="identifier">point_xy</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">&gt;,</span> <span class="keyword">true</span><span class="special">,</span> <span class="keyword">false</span> <span class="comment">// cw, open polygon</span>
 249                 <span class="special">&gt;</span>
 250         <span class="special">&gt;</span> <span class="identifier">mp</span><span class="special">;</span>
 251     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">read_wkt</span><span class="special">(</span><span class="string">"MULTIPOLYGON(((0 0,0 10,10 0),(1 1,8 1,1 8)),((10 10,10 20,20 10)))"</span><span class="special">,</span> <span class="identifier">mp</span><span class="special">);</span>
 252     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"Number of segments: "</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">num_segments</span><span class="special">(</span><span class="identifier">mp</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>
 253     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 254 <span class="special">}</span>
 255 </pre>
 256 <p>
 257         </p>
 258 <p>
 259           Output:
 260         </p>
 261 <pre class="programlisting">Number of segments: 9
 262 </pre>
 263 </div>
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 269         Distributed under the Boost Software License, Version 1.0. (See accompanying
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