1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>num_segments</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="../algorithms.html" title="Algorithms"> 9<link rel="prev" href="num_points.html" title="num_points"> 10<link rel="next" href="overlaps.html" title="overlaps"> 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="num_points.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../algorithms.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="overlaps.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.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="idm45635691383872"></a> 31Calculates 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"><</span><span class="keyword">typename</span> <span class="identifier">Geometry</span><span class="special">></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">&</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 & 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"><</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></code> 122 </p> 123<p> 124 Or 125 </p> 126<p> 127 <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">algorithms</span><span class="special">/</span><span class="identifier">num_segments</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></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"><</span><span class="identifier">iostream</span><span class="special">></span> 237 238<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> 239<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> 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"><</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"><</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"><</span><span class="keyword">double</span><span class="special">>,</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">></span> 250 <span class="special">></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"><<</span> <span class="string">"Number of segments: "</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">num_segments</span><span class="special">(</span><span class="identifier">mp</span><span class="special">)</span> <span class="special"><<</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> 264<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 265<td align="left"></td> 266<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 267 Wulkiewicz, Oracle and/or its affiliates<p> 268 Distributed under the Boost Software License, Version 1.0. (See accompanying 269 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>) 270 </p> 271</div></td> 272</tr></table> 273<hr> 274<div class="spirit-nav"> 275<a accesskey="p" href="num_points.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../algorithms.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="overlaps.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 276</div> 277</body> 278</html> 279
