1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>strategy::buffer::distance_symmetric</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Chapter 1. Geometry"> 8<link rel="up" href="../strategies.html" title="Strategies"> 9<link rel="prev" href="strategy_buffer_end_flat.html" title="strategy::buffer::end_flat"> 10<link rel="next" href="strategy_buffer_distance_asymmetric.html" title="strategy::buffer::distance_asymmetric"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a href="../../../../../../../libs/libraries.htm">Libraries</a></td> 17<td align="center"><a href="http://www.boost.org/users/people.html">People</a></td> 18<td align="center"><a href="http://www.boost.org/users/faq.html">FAQ</a></td> 19<td align="center"><a href="../../../../../../../more/index.htm">More</a></td> 20</tr></table> 21<hr> 22<div class="spirit-nav"> 23<a accesskey="p" href="strategy_buffer_end_flat.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../strategies.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="strategy_buffer_distance_asymmetric.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 24</div> 25<div class="section"> 26<div class="titlepage"><div><div><h4 class="title"> 27<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric"></a><a class="link" href="strategy_buffer_distance_symmetric.html" title="strategy::buffer::distance_symmetric">strategy::buffer::distance_symmetric</a> 28</h4></div></div></div> 29<p> 30 <a class="indexterm" name="idm45635670772608"></a><a class="indexterm" name="idm45635670771920"></a><a class="indexterm" name="idm45635670771232"></a> 31Let the buffer algorithm create buffers with same distances. 32 </p> 33<h6> 34<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h0"></a> 35 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.synopsis"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.synopsis">Synopsis</a> 36 </h6> 37<p> 38</p> 39<pre class="programlisting"><span class="keyword">template</span><span class="special"><</span><span class="keyword">typename</span> <span class="identifier">NumericType</span><span class="special">></span> 40<span class="keyword">class</span> <span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">distance_symmetric</span> 41<span class="special">{</span> 42 <span class="comment">// ...</span> 43<span class="special">};</span> 44</pre> 45<p> 46 </p> 47<h6> 48<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h1"></a> 49 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.template_parameter_s_"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.template_parameter_s_">Template 50 parameter(s)</a> 51 </h6> 52<div class="informaltable"><table class="table"> 53<colgroup> 54<col> 55<col> 56</colgroup> 57<thead><tr> 58<th> 59 <p> 60 Parameter 61 </p> 62 </th> 63<th> 64 <p> 65 Description 66 </p> 67 </th> 68</tr></thead> 69<tbody><tr> 70<td> 71 <p> 72 typename NumericType 73 </p> 74 </td> 75<td> 76 <p> 77 numerical type (int, double, ttmath, ...) 78 </p> 79 </td> 80</tr></tbody> 81</table></div> 82<h6> 83<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h2"></a> 84 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.constructor_s_"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.constructor_s_">Constructor(s)</a> 85 </h6> 86<div class="informaltable"><table class="table"> 87<colgroup> 88<col> 89<col> 90<col> 91</colgroup> 92<thead><tr> 93<th> 94 <p> 95 Function 96 </p> 97 </th> 98<th> 99 <p> 100 Description 101 </p> 102 </th> 103<th> 104 <p> 105 Parameters 106 </p> 107 </th> 108</tr></thead> 109<tbody><tr> 110<td> 111 <p> 112</p> 113<pre xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" class="table-programlisting"><span class="identifier">distance_symmetric</span><span class="special">(</span><span class="identifier">NumericType</span> <span class="keyword">const</span> <span class="special">&</span> <span class="identifier">distance</span><span class="special">)</span></pre> 114<p> 115 </p> 116 </td> 117<td> 118 <p> 119 Constructs the strategy, a distance must be specified. 120 </p> 121 </td> 122<td> 123 <p> 124 <span class="bold"><strong>NumericType const &</strong></span>: <span class="emphasis"><em>distance</em></span>: 125 The distance (or radius) of the buffer 126 </p> 127 </td> 128</tr></tbody> 129</table></div> 130<h6> 131<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h3"></a> 132 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.header"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.header">Header</a> 133 </h6> 134<p> 135 <code class="computeroutput"><span class="preprocessor">#include</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">strategies</span><span class="special">/</span><span class="identifier">agnostic</span><span class="special">/</span><span class="identifier">buffer_distance_symmetric</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code> 136 </p> 137<h6> 138<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h4"></a> 139 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.example"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.example">Example</a> 140 </h6> 141<p> 142 Shows how the distance_symmetric strategy can be used as a DistanceStrategy 143 to create symmetric buffers 144 </p> 145<p> 146</p> 147<pre class="programlisting"><span class="preprocessor">#include</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">hpp</span><span class="special">></span> 148<span class="preprocessor">#include</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">geometries</span><span class="special">/</span><span class="identifier">point_xy</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 149<span class="preprocessor">#include</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">geometries</span><span class="special">/</span><span class="identifier">geometries</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> 150 151 152<span class="keyword">int</span> <span class="identifier">main</span><span class="special">()</span> 153<span class="special">{</span> 154 <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"><</span><span class="keyword">double</span><span class="special">></span> <span class="identifier">point</span><span class="special">;</span> 155 <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">linestring</span><span class="special"><</span><span class="identifier">point</span><span class="special">></span> <span class="identifier">linestring</span><span class="special">;</span> 156 <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"><</span><span class="identifier">point</span><span class="special">></span> <span class="identifier">polygon</span><span class="special">;</span> 157 158 <span class="comment">// Declare the symmetric distance strategy</span> 159 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">distance_symmetric</span><span class="special"><</span><span class="keyword">double</span><span class="special">></span> <span class="identifier">distance_strategy</span><span class="special">(</span><span class="number">0.5</span><span class="special">);</span> 160 161 <span class="comment">// Declare other strategies</span> 162 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">side_straight</span> <span class="identifier">side_strategy</span><span class="special">;</span> 163 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">join_round</span> <span class="identifier">join_strategy</span><span class="special">;</span> 164 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">end_round</span> <span class="identifier">end_strategy</span><span class="special">;</span> 165 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">strategy</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">::</span><span class="identifier">point_circle</span> <span class="identifier">point_strategy</span><span class="special">;</span> 166 167 <span class="comment">// Declare/fill a multi linestring</span> 168 <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_linestring</span><span class="special"><</span><span class="identifier">linestring</span><span class="special">></span> <span class="identifier">ml</span><span class="special">;</span> 169 <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">"MULTILINESTRING((3 5,5 10,7 5),(7 7,11 10,15 7,19 10))"</span><span class="special">,</span> <span class="identifier">ml</span><span class="special">);</span> 170 171 <span class="comment">// Create the buffered geometry with left/right the same distance</span> 172 <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><span class="special"><</span><span class="identifier">polygon</span><span class="special">></span> <span class="identifier">result</span><span class="special">;</span> 173 <span class="identifier">boost</span><span class="special">::</span><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">buffer</span><span class="special">(</span><span class="identifier">ml</span><span class="special">,</span> <span class="identifier">result</span><span class="special">,</span> 174 <span class="identifier">distance_strategy</span><span class="special">,</span> <span class="identifier">side_strategy</span><span class="special">,</span> 175 <span class="identifier">join_strategy</span><span class="special">,</span> <span class="identifier">end_strategy</span><span class="special">,</span> <span class="identifier">point_strategy</span><span class="special">);</span> 176 177 178 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 179<span class="special">}</span> 180</pre> 181<p> 182 </p> 183<h6> 184<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h5"></a> 185 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.output"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.output">Output</a> 186 </h6> 187<p> 188 <span class="inlinemediaobject"><img src="../../../img/strategies/buffer_distance_symmetric.png" alt="buffer_distance_symmetric"></span> 189 </p> 190<h6> 191<a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.h6"></a> 192 <span class="phrase"><a name="geometry.reference.strategies.strategy_buffer_distance_symmetric.see_also"></a></span><a class="link" href="strategy_buffer_distance_symmetric.html#geometry.reference.strategies.strategy_buffer_distance_symmetric.see_also">See 193 also</a> 194 </h6> 195<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 196<li class="listitem"> 197 <a class="link" href="../algorithms/buffer/buffer_7_with_strategies.html" title="buffer (with strategies)">buffer 198 (with strategies)</a> 199 </li> 200<li class="listitem"> 201 <a class="link" href="strategy_buffer_distance_asymmetric.html" title="strategy::buffer::distance_asymmetric">distance_asymmetric</a> 202 </li> 203</ul></div> 204</div> 205<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 206<td align="left"></td> 207<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 208 Wulkiewicz, Oracle and/or its affiliates<p> 209 Distributed under the Boost Software License, Version 1.0. (See accompanying 210 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>) 211 </p> 212</div></td> 213</tr></table> 214<hr> 215<div class="spirit-nav"> 216<a accesskey="p" href="strategy_buffer_end_flat.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../strategies.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="strategy_buffer_distance_asymmetric.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 217</div> 218</body> 219</html> 220
