libs/geometry/doc/html/geometry/reference/adapted/boost_range/filtered.html

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  26 <div class="titlepage"><div><div><h5 class="title">
  27 <a name="geometry.reference.adapted.boost_range.filtered"></a><a class="link" href="filtered.html" title="Boost.Range filtered">Boost.Range
  28           filtered</a>
  29 </h5></div></div></div>
  30 <p>
  31             Boost.Range filtered range adaptor is adapted to Boost.Geometry
  32           </p>
  33 <h6>
  34 <a name="geometry.reference.adapted.boost_range.filtered.h0"></a>
  35             <span class="phrase"><a name="geometry.reference.adapted.boost_range.filtered.description"></a></span><a class="link" href="filtered.html#geometry.reference.adapted.boost_range.filtered.description">Description</a>
  36           </h6>
  37 <p>
  38             Boost.Range filtered range adaptor filters a range.
  39           </p>
  40 <h6>
  41 <a name="geometry.reference.adapted.boost_range.filtered.h1"></a>
  42             <span class="phrase"><a name="geometry.reference.adapted.boost_range.filtered.model_of"></a></span><a class="link" href="filtered.html#geometry.reference.adapted.boost_range.filtered.model_of">Model
  43             of</a>
  44           </h6>
  45 <p>
  46             The Boost.Range filtered range adaptor takes over the model of the original
  47             geometry, which might be:
  48           </p>
  49 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  50 <li class="listitem">
  51                 a linestring
  52               </li>
  53 <li class="listitem">
  54                 a ring
  55               </li>
  56 <li class="listitem">
  57                 a multi_point
  58               </li>
  59 <li class="listitem">
  60                 a multi_linestring
  61               </li>
  62 <li class="listitem">
  63                 a multi_polygon
  64               </li>
  65 </ul></div>
  66 <h6>
  67 <a name="geometry.reference.adapted.boost_range.filtered.h2"></a>
  68             <span class="phrase"><a name="geometry.reference.adapted.boost_range.filtered.header"></a></span><a class="link" href="filtered.html#geometry.reference.adapted.boost_range.filtered.header">Header</a>
  69           </h6>
  70 <p>
  71             <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">geometries</span><span class="special">/</span><span class="identifier">adapted</span><span class="special">/</span><span class="identifier">boost_range</span><span class="special">/</span><span class="identifier">filtered</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span></code>
  72           </p>
  73 <p>
  74             The standard header <code class="computeroutput"><span class="identifier">boost</span><span class="special">/</span><span class="identifier">geometry</span><span class="special">.</span><span class="identifier">hpp</span></code>
  75             does not include this header.
  76           </p>
  77 <h6>
  78 <a name="geometry.reference.adapted.boost_range.filtered.h3"></a>
  79             <span class="phrase"><a name="geometry.reference.adapted.boost_range.filtered.example"></a></span><a class="link" href="filtered.html#geometry.reference.adapted.boost_range.filtered.example">Example</a>
  80           </h6>
  81 <p>
  82             Shows how to use a Boost.Geometry linestring, filtered by Boost.Range
  83             adaptor
  84           </p>
  85 <p>
  86 </p>
  87 <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special">&lt;</span><span class="identifier">iostream</span><span class="special">&gt;</span>
  88
  89 <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>
  90 <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">linestring</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
  91 <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>
  92 <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_range</span><span class="special">/</span><span class="identifier">filtered</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">&gt;</span>
  93
  94 <span class="keyword">struct</span> <span class="identifier">not_two</span>
  95 <span class="special">{</span>
  96     <span class="keyword">template</span> <span class="special">&lt;</span><span class="keyword">typename</span> <span class="identifier">P</span><span class="special">&gt;</span>
  97     <span class="keyword">bool</span> <span class="keyword">operator</span><span class="special">()(</span><span class="identifier">P</span> <span class="keyword">const</span><span class="special">&amp;</span> <span class="identifier">p</span><span class="special">)</span> <span class="keyword">const</span>
  98     <span class="special">{</span>
  99         <span class="keyword">return</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">&lt;</span><span class="number">1</span><span class="special">&gt;(</span><span class="identifier">p</span><span class="special">)</span> <span class="special">!=</span> <span class="number">2</span><span class="special">;</span>
 100     <span class="special">}</span>
 101 <span class="special">};</span>
 102
 103
 104 <span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span>
 105 <span class="special">{</span>
 106     <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">int</span><span class="special">&gt;</span> <span class="identifier">xy</span><span class="special">;</span>
 107     <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">linestring</span><span class="special">&lt;</span><span class="identifier">xy</span><span class="special">&gt;</span> <span class="identifier">line</span><span class="special">;</span>
 108     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">0</span><span class="special">,</span> <span class="number">0</span><span class="special">));</span>
 109     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">1</span><span class="special">,</span> <span class="number">1</span><span class="special">));</span>
 110     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">2</span><span class="special">,</span> <span class="number">2</span><span class="special">));</span>
 111     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">3</span><span class="special">,</span> <span class="number">1</span><span class="special">));</span>
 112     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">4</span><span class="special">,</span> <span class="number">0</span><span class="special">));</span>
 113     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">5</span><span class="special">,</span> <span class="number">1</span><span class="special">));</span>
 114     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">6</span><span class="special">,</span> <span class="number">2</span><span class="special">));</span>
 115     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">7</span><span class="special">,</span> <span class="number">1</span><span class="special">));</span>
 116     <span class="identifier">line</span><span class="special">.</span><span class="identifier">push_back</span><span class="special">(</span><span class="identifier">xy</span><span class="special">(</span><span class="number">8</span><span class="special">,</span> <span class="number">0</span><span class="special">));</span>
 117
 118     <span class="keyword">using</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">adaptors</span><span class="special">::</span><span class="identifier">filtered</span><span class="special">;</span>
 119     <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span>
 120         <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">line</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>
 121         <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">line</span> <span class="special">|</span> <span class="identifier">filtered</span><span class="special">(</span><span class="identifier">not_two</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>
 122         <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">line</span> <span class="special">|</span> <span class="identifier">filtered</span><span class="special">(</span><span class="identifier">not_two</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>
 123
 124     <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span>
 125 <span class="special">}</span>
 126 </pre>
 127 <p>
 128           </p>
 129 <p>
 130             Output:
 131           </p>
 132 <pre class="programlisting">11.3137
 133 9.65685
 134 ((0, 0), (1, 1), (3, 1), (4, 0), (5, 1), (7, 1), (8, 0))
 135 </pre>
 136 </div>
 137 <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr>
 138 <td align="left"></td>
 139 <td align="right"><div class="copyright-footer">Copyright &#169; 2009-2017 Barend
 140       Gehrels, Bruno Lalande, Mateusz Loskot, Adam Wulkiewicz, Oracle and/or its
 141       affiliates<p>
 142         Distributed under the Boost Software License, Version 1.0. (See accompanying
 143         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>)
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