libs/geometry/doc/html/geometry/reference/algorithms/for_each/for_each_point.html

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  25 <div class="section">
  26 <div class="titlepage"><div><div><h5 class="title">
  27 <a name="geometry.reference.algorithms.for_each.for_each_point"></a><a class="link" href="for_each_point.html" title="for_each_point">for_each_point</a>
  28 </h5></div></div></div>
  29 <p>
  30             <a class="indexterm" name="idm46186998648672"></a>
  31 Applies function <span class="bold"><strong>f</strong></span> to each point.
  32           </p>
  33 <h6>
  34 <a name="geometry.reference.algorithms.for_each.for_each_point.h0"></a>
  35             <span class="phrase"><a name="geometry.reference.algorithms.for_each.for_each_point.description"></a></span><a class="link" href="for_each_point.html#geometry.reference.algorithms.for_each.for_each_point.description">Description</a>
  36           </h6>
  37 <p>
  38             Applies a function <span class="bold"><strong>f</strong></span> (functor, having
  39             operator() defined) to each point making up the geometry
  40           </p>
  41 <h6>
  42 <a name="geometry.reference.algorithms.for_each.for_each_point.h1"></a>
  43             <span class="phrase"><a name="geometry.reference.algorithms.for_each.for_each_point.synopsis"></a></span><a class="link" href="for_each_point.html#geometry.reference.algorithms.for_each.for_each_point.synopsis">Synopsis</a>
  44           </h6>
  45 <p>
  46 </p>
  47 <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">,</span> <span class="keyword">typename</span> <span class="identifier">Functor</span><span class="special">&gt;</span>
  48 <span class="identifier">Functor</span> <span class="identifier">for_each_point</span><span class="special">(</span><span class="identifier">Geometry</span> <span class="special">&amp;</span> <span class="identifier">geometry</span><span class="special">,</span> <span class="identifier">Functor</span> <span class="identifier">f</span><span class="special">)</span></pre>
  49 <p>
  50           </p>
  51 <h6>
  52 <a name="geometry.reference.algorithms.for_each.for_each_point.h2"></a>
  53             <span class="phrase"><a name="geometry.reference.algorithms.for_each.for_each_point.parameters"></a></span><a class="link" href="for_each_point.html#geometry.reference.algorithms.for_each.for_each_point.parameters">Parameters</a>
  54           </h6>
  55 <div class="informaltable"><table class="table">
  56 <colgroup>
  57 <col>
  58 <col>
  59 <col>
  60 <col>
  61 </colgroup>
  62 <thead><tr>
  63 <th>
  64                     <p>
  65                       Type
  66                     </p>
  67                   </th>
  68 <th>
  69                     <p>
  70                       Concept
  71                     </p>
  72                   </th>
  73 <th>
  74                     <p>
  75                       Name
  76                     </p>
  77                   </th>
  78 <th>
  79                     <p>
  80                       Description
  81                     </p>
  82                   </th>
  83 </tr></thead>
  84 <tbody>
  85 <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
 104                     </p>
 105                   </td>
 106 </tr>
 107 <tr>
 108 <td>
 109                     <p>
 110                       Functor
 111                     </p>
 112                   </td>
 113 <td>
 114                     <p>
 115                       Function or class with operator()
 116                     </p>
 117                   </td>
 118 <td>
 119                     <p>
 120                       f
 121                     </p>
 122                   </td>
 123 <td>
 124                     <p>
 125                       Unary function, taking a point as argument
 126                     </p>
 127                   </td>
 128 </tr>
 129 </tbody>
 130 </table></div>
 131 <h6>
 132 <a name="geometry.reference.algorithms.for_each.for_each_point.h3"></a>
 133             <span class="phrase"><a name="geometry.reference.algorithms.for_each.for_each_point.header"></a></span><a class="link" href="for_each_point.html#geometry.reference.algorithms.for_each.for_each_point.header">Header</a>
 134           </h6>
 135 <p>
 136             Either
 137           </p>
 138 <p>
 139             <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>
 140           </p>
 141 <p>
 142             Or
 143           </p>
 144 <p>
 145             <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">for_each</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 146           </p>
 147 <h6>
 148 <a name="geometry.reference.algorithms.for_each.for_each_point.h4"></a>
 149             <span class="phrase"><a name="geometry.reference.algorithms.for_each.for_each_point.conformance"></a></span><a class="link" href="for_each_point.html#geometry.reference.algorithms.for_each.for_each_point.conformance">Conformance</a>
 150           </h6>
 151 <p>
 152             The function for_each_point is not defined by OGC.
 153           </p>
 154 <p>
 155             The function for_each_point conforms to the std::for_each function of
 156             the C++ std-library.
 157           </p>
 158 <h6>
 159 <a name="geometry.reference.algorithms.for_each.for_each_point.h5"></a>
 160             <span class="phrase"><a name="geometry.reference.algorithms.for_each.for_each_point.example"></a></span><a class="link" href="for_each_point.html#geometry.reference.algorithms.for_each.for_each_point.example">Example</a>
 161           </h6>
 162 <p>
 163             Convenient usage of for_each_point, rounding all points of a geometry
 164           </p>
 165 <p>
 166 </p>
 167 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 168
 169 <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>
 170 <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>
 171 <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>
 172
 173
 174
 175 <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Point</span><span class="special">&gt;</span>
 176 <span class="keyword">class</span> <span class="identifier">round_coordinates</span>
 177 <span class="special">{</span>
 178 <span class="keyword">private</span> <span class="special">:</span>
 179     <span class="keyword">typedef</span> <span class="keyword">typename</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">coordinate_type</span><span class="special">&lt;</span><span class="identifier">Point</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">coordinate_type</span><span class="special">;</span>
 180     <span class="identifier">coordinate_type</span> <span class="identifier">factor</span><span class="special">;</span>
 181
 182     <span class="keyword">inline</span> <span class="identifier">coordinate_type</span> <span class="identifier">round</span><span class="special">(</span><span class="identifier">coordinate_type</span> <span class="identifier">value</span><span class="special">)</span>
 183     <span class="special">{</span>
 184         <span class="keyword">return</span> <span class="identifier">floor</span><span class="special">(</span><span class="number">0.5</span> <span class="special">+</span> <span class="special">(</span><span class="identifier">value</span> <span class="special">/</span> <span class="identifier">factor</span><span class="special">))</span> <span class="special">*</span> <span class="identifier">factor</span><span class="special">;</span>
 185     <span class="special">}</span>
 186
 187 <span class="keyword">public</span> <span class="special">:</span>
 188     <span class="identifier">round_coordinates</span><span class="special">(</span><span class="identifier">coordinate_type</span> <span class="identifier">f</span><span class="special">)</span>
 189         <span class="special">:</span> <span class="identifier">factor</span><span class="special">(</span><span class="identifier">f</span><span class="special">)</span>
 190     <span class="special">{}</span>
 191
 192     <span class="keyword">inline</span> <span class="keyword">void</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">Point</span><span class="special">&amp;</span> <span class="identifier">p</span><span class="special">)</span>
 193     <span class="special">{</span>
 194         <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">get</span><span class="special">;</span>
 195         <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">set</span><span class="special">;</span>
 196         <span class="identifier">set</span><span class="special">&lt;</span><span class="number">0</span><span class="special">&gt;(</span><span class="identifier">p</span><span class="special">,</span> <span class="identifier">round</span><span class="special">(</span><span class="identifier">get</span><span class="special">&lt;</span><span class="number">0</span><span class="special">&gt;(</span><span class="identifier">p</span><span class="special">)));</span>
 197         <span class="identifier">set</span><span class="special">&lt;</span><span class="number">1</span><span class="special">&gt;(</span><span class="identifier">p</span><span class="special">,</span> <span class="identifier">round</span><span class="special">(</span><span class="identifier">get</span><span class="special">&lt;</span><span class="number">1</span><span class="special">&gt;(</span><span class="identifier">p</span><span class="special">)));</span>
 198     <span class="special">}</span>
 199 <span class="special">};</span>
 200
 201
 202 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 203 <span class="special">{</span>
 204     <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">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="identifier">point</span><span class="special">;</span>
 205     <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">poly</span><span class="special">;</span>
 206     <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">"POLYGON((0 0,1.123 9.987,8.876 2.234,0 0),(3.345 4.456,7.654 8.765,9.123 5.432,3.345 4.456))"</span><span class="special">,</span> <span class="identifier">poly</span><span class="special">);</span>
 207     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">for_each_point</span><span class="special">(</span><span class="identifier">poly</span><span class="special">,</span> <span class="identifier">round_coordinates</span><span class="special">&lt;</span><span class="identifier">point</span><span class="special">&gt;(</span><span class="number">0.1</span><span class="special">));</span>
 208     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"Rounded: "</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">wkt</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>
 209     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 210 <span class="special">}</span>
 211 </pre>
 212 <p>
 213           </p>
 214 <p>
 215             Output:
 216           </p>
 217 <pre class="programlisting">Rounded: POLYGON((0 0,1.1 10,8.9 2.2,0 0),(3.3 4.5,7.7 8.8,9.1 5.4,3.3 4.5))
 218 </pre>
 219 <p>
 220             Sample using for_each_point, using a function to list coordinates
 221           </p>
 222 <p>
 223 </p>
 224 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 225
 226 <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>
 227 <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>
 228 <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>
 229
 230
 231 <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Point</span><span class="special">&gt;</span>
 232 <span class="keyword">void</span> <span class="identifier">list_coordinates</span><span class="special">(</span><span class="identifier">Point</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">p</span><span class="special">)</span>
 233 <span class="special">{</span>
 234     <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">get</span><span class="special">;</span>
 235     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">"x = "</span> <span class="special">&lt;&lt;</span> <span class="identifier">get</span><span class="special">&lt;</span><span class="number">0</span><span class="special">&gt;(</span><span class="identifier">p</span><span class="special">)</span> <span class="special">&lt;&lt;</span> <span class="string">" y = "</span> <span class="special">&lt;&lt;</span> <span class="identifier">get</span><span class="special">&lt;</span><span class="number">1</span><span class="special">&gt;(</span><span class="identifier">p</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>
 236 <span class="special">}</span>
 237
 238 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 239 <span class="special">{</span>
 240     <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">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="identifier">point</span><span class="special">;</span>
 241     <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">poly</span><span class="special">;</span>
 242     <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">"POLYGON((0 0,0 4,4 0,0 0))"</span><span class="special">,</span> <span class="identifier">poly</span><span class="special">);</span>
 243     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">for_each_point</span><span class="special">(</span><span class="identifier">poly</span><span class="special">,</span> <span class="identifier">list_coordinates</span><span class="special">&lt;</span><span class="identifier">point</span><span class="special">&gt;);</span>
 244     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 245 <span class="special">}</span>
 246 </pre>
 247 <p>
 248           </p>
 249 <p>
 250             Output:
 251           </p>
 252 <pre class="programlisting">x = 0 y = 0
 253 x = 0 y = 4
 254 x = 4 y = 0
 255 x = 0 y = 0
 256 </pre>
 257 </div>
 258 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 259 <td align="left"></td>
 260 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam
 261       Wulkiewicz, Oracle and/or its affiliates<p>
 262         Distributed under the Boost Software License, Version 1.0. (See accompanying
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