libs/geometry/doc/html/geometry/reference/views/segment_view.html

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  25 <div class="section">
  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="geometry.reference.views.segment_view"></a><a class="link" href="segment_view.html" title="segment_view">segment_view</a>
  28 </h4></div></div></div>
  29 <p>
  30           <a class="indexterm" name="idm46186970474720"></a>
  31 Makes a segment behave like a linestring or a range.
  32         </p>
  33 <h6>
  34 <a name="geometry.reference.views.segment_view.h0"></a>
  35           <span class="phrase"><a name="geometry.reference.views.segment_view.description"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.description">Description</a>
  36         </h6>
  37 <p>
  38           Adapts a segment to the Boost.Range concept, enabling the user to iterate
  39           the two segment points. The segment_view is registered as a LineString
  40           Concept
  41         </p>
  42 <h6>
  43 <a name="geometry.reference.views.segment_view.h1"></a>
  44           <span class="phrase"><a name="geometry.reference.views.segment_view.model_of"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.model_of">Model
  45           of</a>
  46         </h6>
  47 <p>
  48           <a class="link" href="../concepts/concept_linestring.html" title="Linestring Concept">LineString
  49           Concept</a>
  50         </p>
  51 <h6>
  52 <a name="geometry.reference.views.segment_view.h2"></a>
  53           <span class="phrase"><a name="geometry.reference.views.segment_view.synopsis"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.synopsis">Synopsis</a>
  54         </h6>
  55 <p>
  56 </p>
  57 <pre class="programlisting"><span class="keyword">template</span><span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">Segment</span><span class="special">&gt;</span>
  58 <span class="keyword">struct</span> <span class="identifier">segment_view</span>
  59       <span class="special">:</span> <span class="keyword">public</span> <span class="identifier">detail</span><span class="special">::</span><span class="identifier">points_view</span><span class="special">&lt;</span> <span class="identifier">geometry</span><span class="special">::</span><span class="identifier">point_type</span><span class="special">&lt;</span> <span class="identifier">Segment</span> <span class="special">&gt;::</span><span class="identifier">type</span><span class="special">,</span> <span class="number">2</span> <span class="special">&gt;</span>
  60 <span class="special">{</span>
  61   <span class="comment">// ...</span>
  62 <span class="special">};</span>
  63 </pre>
  64 <p>
  65         </p>
  66 <h6>
  67 <a name="geometry.reference.views.segment_view.h3"></a>
  68           <span class="phrase"><a name="geometry.reference.views.segment_view.template_parameter_s_"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.template_parameter_s_">Template
  69           parameter(s)</a>
  70         </h6>
  71 <div class="informaltable"><table class="table">
  72 <colgroup>
  73 <col>
  74 <col>
  75 </colgroup>
  76 <thead><tr>
  77 <th>
  78                   <p>
  79                     Parameter
  80                   </p>
  81                 </th>
  82 <th>
  83                   <p>
  84                     Description
  85                   </p>
  86                 </th>
  87 </tr></thead>
  88 <tbody><tr>
  89 <td>
  90                   <p>
  91                     typename Segment
  92                   </p>
  93                 </td>
  94 <td>
  95                   <p>
  96                     A type fulfilling the Segment Concept
  97                   </p>
  98                 </td>
  99 </tr></tbody>
 100 </table></div>
 101 <h6>
 102 <a name="geometry.reference.views.segment_view.h4"></a>
 103           <span class="phrase"><a name="geometry.reference.views.segment_view.constructor_s_"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.constructor_s_">Constructor(s)</a>
 104         </h6>
 105 <div class="informaltable"><table class="table">
 106 <colgroup>
 107 <col>
 108 <col>
 109 <col>
 110 </colgroup>
 111 <thead><tr>
 112 <th>
 113                   <p>
 114                     Function
 115                   </p>
 116                 </th>
 117 <th>
 118                   <p>
 119                     Description
 120                   </p>
 121                 </th>
 122 <th>
 123                   <p>
 124                     Parameters
 125                   </p>
 126                 </th>
 127 </tr></thead>
 128 <tbody><tr>
 129 <td>
 130                   <p>
 131 </p>
 132 <pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">segment_view</span><span class="special">(</span><span class="identifier">Segment</span> <span class="keyword">const</span> <span class="special">&amp;</span> <span class="identifier">segment</span><span class="special">)</span></pre>
 133 <p>
 134                   </p>
 135                 </td>
 136 <td>
 137                   <p>
 138                     Constructor accepting the segment to adapt.
 139                   </p>
 140                 </td>
 141 <td>
 142                   <p>
 143                     <span class="bold"><strong>Segment const &amp;</strong></span>: <span class="emphasis"><em>segment</em></span>:
 144                   </p>
 145                 </td>
 146 </tr></tbody>
 147 </table></div>
 148 <h6>
 149 <a name="geometry.reference.views.segment_view.h5"></a>
 150           <span class="phrase"><a name="geometry.reference.views.segment_view.header"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.header">Header</a>
 151         </h6>
 152 <p>
 153           Either
 154         </p>
 155 <p>
 156           <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>
 157         </p>
 158 <p>
 159           Or
 160         </p>
 161 <p>
 162           <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">views</span><span class="special">/</span><span class="identifier">segment_view</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
 163         </p>
 164 <h6>
 165 <a name="geometry.reference.views.segment_view.h6"></a>
 166           <span class="phrase"><a name="geometry.reference.views.segment_view.complexity"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.complexity">Complexity</a>
 167         </h6>
 168 <p>
 169           Compile time
 170         </p>
 171 <h6>
 172 <a name="geometry.reference.views.segment_view.h7"></a>
 173           <span class="phrase"><a name="geometry.reference.views.segment_view.example"></a></span><a class="link" href="segment_view.html#geometry.reference.views.segment_view.example">Example</a>
 174         </h6>
 175 <p>
 176           Shows usage of the Boost.Range compatible view on a box
 177         </p>
 178 <p>
 179 </p>
 180 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
 181
 182 <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>
 183
 184
 185 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 186 <span class="special">{</span>
 187     <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">segment</span>
 188         <span class="special">&lt;</span>
 189             <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">point</span><span class="special">&lt;</span><span class="keyword">double</span><span class="special">,</span> <span class="number">2</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">cs</span><span class="special">::</span><span class="identifier">cartesian</span><span class="special">&gt;</span>
 190         <span class="special">&gt;</span> <span class="identifier">segment_type</span><span class="special">;</span>
 191
 192     <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">segment_view</span><span class="special">&lt;</span><span class="identifier">segment_type</span><span class="special">&gt;</span> <span class="identifier">segment_view</span><span class="special">;</span>
 193
 194     <span class="identifier">segment_type</span> <span class="identifier">segment</span><span class="special">;</span>
 195     <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">assign_values</span><span class="special">(</span><span class="identifier">segment</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">1</span><span class="special">,</span> <span class="number">1</span><span class="special">);</span>
 196
 197     <span class="identifier">segment_view</span> <span class="identifier">view</span><span class="special">(</span><span class="identifier">segment</span><span class="special">);</span>
 198
 199     <span class="comment">// Iterating over the points of this segment</span>
 200     <span class="keyword">for</span> <span class="special">(</span><span class="identifier">boost</span><span class="special">::</span><span class="identifier">range_iterator</span><span class="special">&lt;</span><span class="identifier">segment_view</span> <span class="keyword">const</span><span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">it</span> <span class="special">=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">begin</span><span class="special">(</span><span class="identifier">view</span><span class="special">);</span>
 201         <span class="identifier">it</span> <span class="special">!=</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">end</span><span class="special">(</span><span class="identifier">view</span><span class="special">);</span> <span class="special">++</span><span class="identifier">it</span><span class="special">)</span>
 202     <span class="special">{</span>
 203         <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special">&lt;&lt;</span> <span class="string">" "</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">it</span><span class="special">);</span>
 204     <span class="special">}</span>
 205     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</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>
 206
 207     <span class="comment">// Note that a segment_view is tagged as a linestring, so supports length etc.</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">"Length: "</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">length</span><span class="special">(</span><span class="identifier">view</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
 210     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 211 <span class="special">}</span>
 212 </pre>
 213 <p>
 214         </p>
 215 <p>
 216           Output:
 217         </p>
 218 <pre class="programlisting">(0, 0) (1, 1)
 219 Length: 1.41421
 220 </pre>
 221 </div>
 222 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 223 <td align="left"></td>
 224 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam
 225       Wulkiewicz, Oracle and/or its affiliates<p>
 226         Distributed under the Boost Software License, Version 1.0. (See accompanying
 227         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>)
 228       </p>
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