libs/geometry/doc/html/geometry/reference/concepts/concept_point.html

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   4 <title>Point Concept</title>
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  26 <div class="titlepage"><div><div><h4 class="title">
  27 <a name="geometry.reference.concepts.concept_point"></a><a class="link" href="concept_point.html" title="Point Concept">Point Concept</a>
  28 </h4></div></div></div>
  29 <h6>
  30 <a name="geometry.reference.concepts.concept_point.h0"></a>
  31           <span class="phrase"><a name="geometry.reference.concepts.concept_point.description"></a></span><a class="link" href="concept_point.html#geometry.reference.concepts.concept_point.description">Description</a>
  32         </h6>
  33 <p>
  34           The Point Concept describes the requirements for a point type. All algorithms
  35           in Boost.Geometry will check any geometry arguments against the concept
  36           requirements.
  37         </p>
  38 <p>
  39           A point is <span class="emphasis"><em>an entity that has a location in space or on a plane,
  40           but has no extent</em></span> (<a href="http://en.wikipedia.org/wiki/Point_(geometry)" target="_top">wiki</a>).
  41           The point is the most basic geometry of Boost.Geometry, most other geometries
  42           consist of points. <span class="emphasis"><em>(Exceptions are box and segment, which might
  43           consist of two points but that is not necessarily the case.)</em></span>
  44         </p>
  45 <h6>
  46 <a name="geometry.reference.concepts.concept_point.h1"></a>
  47           <span class="phrase"><a name="geometry.reference.concepts.concept_point.concept_definition"></a></span><a class="link" href="concept_point.html#geometry.reference.concepts.concept_point.concept_definition">Concept
  48           Definition</a>
  49         </h6>
  50 <p>
  51           The Point Concept is defined as following:
  52         </p>
  53 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  54 <li class="listitem">
  55               there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">tag</span></code>,
  56               defining <code class="computeroutput"><span class="identifier">point_tag</span></code>
  57               as type
  58             </li>
  59 <li class="listitem">
  60               there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">coordinate_type</span></code>,
  61               defining the type of its coordinates
  62             </li>
  63 <li class="listitem">
  64               there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">coordinate_system</span></code>,
  65               defining its coordinate system (cartesian, spherical, etc)
  66             </li>
  67 <li class="listitem">
  68               there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">dimension</span></code>,
  69               defining its number of dimensions (2, 3, ...) (hint: derive it conveniently
  70               from <code class="computeroutput"><span class="identifier">boost</span><span class="special">::</span><span class="identifier">mpl</span><span class="special">::</span><span class="identifier">int_</span><span class="special">&lt;</span><span class="identifier">X</span><span class="special">&gt;</span></code>
  71               for X Dimensional)
  72             </li>
  73 <li class="listitem">
  74               there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">access</span></code>,
  75               per dimension, with two functions:
  76               <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; ">
  77 <li class="listitem">
  78                     <code class="computeroutput"><span class="identifier">get</span></code> to get a
  79                     coordinate value
  80                   </li>
  81 <li class="listitem">
  82                     <code class="computeroutput"><span class="identifier">set</span></code> to set a
  83                     coordinate value (this one is not checked for ConstPoint)
  84                   </li>
  85 </ul></div>
  86             </li>
  87 </ul></div>
  88 <h6>
  89 <a name="geometry.reference.concepts.concept_point.h2"></a>
  90           <span class="phrase"><a name="geometry.reference.concepts.concept_point.available_models"></a></span><a class="link" href="concept_point.html#geometry.reference.concepts.concept_point.available_models">Available
  91           Models</a>
  92         </h6>
  93 <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
  94 <li class="listitem">
  95               <a class="link" href="../models/model_point.html" title="model::point">model::point</a>
  96             </li>
  97 <li class="listitem">
  98               <a class="link" href="../models/model_d2_point_xy.html" title="model::d2::point_xy">model::d2::point_xy</a>
  99             </li>
 100 <li class="listitem">
 101               a lat long point (currently in an extension)
 102             </li>
 103 <li class="listitem">
 104               <a class="link" href="../adapted/c_array.html" title="C array">C array</a>
 105             </li>
 106 <li class="listitem">
 107               <a class="link" href="../adapted/boost_array.html" title="Boost.Array">Boost.Array</a>
 108             </li>
 109 <li class="listitem">
 110               <a class="link" href="../adapted/boost_fusion.html" title="Boost.Fusion">Boost.Fusion</a>
 111             </li>
 112 <li class="listitem">
 113               <a class="link" href="../adapted/boost_polygon.html" title="Boost.Polygon">Boost.Polygon</a>
 114             </li>
 115 <li class="listitem">
 116               <a class="link" href="../adapted/boost_tuple.html" title="Boost.Tuple">Boost.Tuple</a>
 117             </li>
 118 <li class="listitem">
 119               other point types, adapted e.g. using one of the <a class="link" href="../adapted.html" title="Adapted models">registration
 120               macro's</a>
 121             </li>
 122 </ul></div>
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 127       Gehrels, Bruno Lalande, Mateusz Loskot, Adam Wulkiewicz, Oracle and/or its
 128       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>
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