1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>Ring Concept</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="../concepts.html" title="Concepts"> 9<link rel="prev" href="concept_box.html" title="Box Concept"> 10<link rel="next" href="concept_segment.html" title="Segment Concept"> 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="concept_box.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../concepts.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="concept_segment.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.concepts.concept_ring"></a><a class="link" href="concept_ring.html" title="Ring Concept">Ring Concept</a> 28</h4></div></div></div> 29<h6> 30<a name="geometry.reference.concepts.concept_ring.h0"></a> 31 <span class="phrase"><a name="geometry.reference.concepts.concept_ring.description"></a></span><a class="link" href="concept_ring.html#geometry.reference.concepts.concept_ring.description">Description</a> 32 </h6> 33<p> 34 The Ring Concept describes the requirements for a ring type. All algorithms 35 in Boost.Geometry will check any geometry arguments against the concept 36 requirements. 37 </p> 38<div class="note"><table border="0" summary="Note"> 39<tr> 40<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td> 41<th align="left">Note</th> 42</tr> 43<tr><td align="left" valign="top"><p> 44 Also called linear ring, but we explicitly refer to a filled feature 45 here 46 </p></td></tr> 47</table></div> 48<h6> 49<a name="geometry.reference.concepts.concept_ring.h1"></a> 50 <span class="phrase"><a name="geometry.reference.concepts.concept_ring.concept_definition"></a></span><a class="link" href="concept_ring.html#geometry.reference.concepts.concept_ring.concept_definition">Concept 51 Definition</a> 52 </h6> 53<p> 54 The Ring Concept is defined as following: 55 </p> 56<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 57<li class="listitem"> 58 there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">tag</span></code> 59 defining <code class="computeroutput"><span class="identifier">ring_tag</span></code> as 60 type 61 </li> 62<li class="listitem"> 63 it must behave like a Boost.Range Random Access Range 64 </li> 65<li class="listitem"> 66 The type defined by the metafunction <code class="computeroutput"><span class="identifier">range_value</span><span class="special"><...>::</span><span class="identifier">type</span></code> 67 must fulfill the <a class="link" href="concept_point.html" title="Point Concept">Point 68 Concept</a> 69 </li> 70<li class="listitem"> 71 there might be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">point_order</span></code> 72 defining the order or orientation of its points, <code class="computeroutput"><span class="identifier">clockwise</span></code> 73 or <code class="computeroutput"><span class="identifier">counterclockwise</span></code> 74 </li> 75<li class="listitem"> 76 there might be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">closure</span></code> 77 defining the closure, <code class="computeroutput"><span class="identifier">open</span></code> 78 or <code class="computeroutput"><span class="identifier">closed</span></code> 79 </li> 80</ul></div> 81<h6> 82<a name="geometry.reference.concepts.concept_ring.h2"></a> 83 <span class="phrase"><a name="geometry.reference.concepts.concept_ring.rules"></a></span><a class="link" href="concept_ring.html#geometry.reference.concepts.concept_ring.rules">Rules</a> 84 </h6> 85<p> 86 Besides the Concepts, which are checks on compile-time, there are rules 87 that valid rings must fulfill. See the <a class="link" href="concept_polygon.html" title="Polygon Concept">Polygon 88 Concept</a> for more information on the rules a polygon (and also a 89 ring) must fulfill. 90 </p> 91<h6> 92<a name="geometry.reference.concepts.concept_ring.h3"></a> 93 <span class="phrase"><a name="geometry.reference.concepts.concept_ring.available_models"></a></span><a class="link" href="concept_ring.html#geometry.reference.concepts.concept_ring.available_models">Available 94 Models</a> 95 </h6> 96<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; "> 97<li class="listitem"> 98 <a class="link" href="../models/model_ring.html" title="model::ring">ring</a> 99 </li> 100<li class="listitem"> 101 a Boost.Polygon polygon_data (requires <code class="computeroutput"><span class="preprocessor">#include</span> 102 <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_polygon</span><span class="special">/</span><span class="identifier">ring</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code>) 103 </li> 104<li class="listitem"> 105 a std::vector (requires <code class="computeroutput"><span class="preprocessor">#include</span> 106 <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">std_as_ring</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code>) 107 </li> 108<li class="listitem"> 109 a std::deque (requires <code class="computeroutput"><span class="preprocessor">#include</span> 110 <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">std_as_ring</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code>) 111 </li> 112</ul></div> 113<div class="note"><table border="0" summary="Note"> 114<tr> 115<td rowspan="2" align="center" valign="top" width="25"><img alt="[Note]" src="../../../../../../../doc/src/images/note.png"></td> 116<th align="left">Note</th> 117</tr> 118<tr><td align="left" valign="top"><p> 119 See also the sample in the <a href="../../../../../../range/doc/html/range/reference/extending/method_2.html" target="_top">Boost.Range 120 documentation</a> showing how a type can be adapted to a Boost.Range 121 to fulfill the concept of a Ring 122 </p></td></tr> 123</table></div> 124</div> 125<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 126<td align="left"></td> 127<td align="right"><div class="copyright-footer">Copyright © 2009-2019 Barend Gehrels, Bruno Lalande, Mateusz Loskot, Adam 128 Wulkiewicz, Oracle and/or its affiliates<p> 129 Distributed under the Boost Software License, Version 1.0. (See accompanying 130 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>) 131 </p> 132</div></td> 133</tr></table> 134<hr> 135<div class="spirit-nav"> 136<a accesskey="p" href="concept_box.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../concepts.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="concept_segment.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 137</div> 138</body> 139</html> 140
