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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="geometry.reference.concepts.concept_polygon"></a><a class="link" href="concept_polygon.html" title="Polygon Concept">Polygon |
| Concept</a> |
| </h4></div></div></div> |
| <a name="geometry.reference.concepts.concept_polygon.description"></a><h6> |
| <a name="geometry.reference.concepts.concept_polygon.description-heading"></a> |
| <a class="link" href="concept_polygon.html#geometry.reference.concepts.concept_polygon.description">Description</a> |
| </h6> |
| <p> |
| The Polygon Concept describes the requirements for a polygon type. All |
| algorithms in Boost.Geometry will check any geometry arguments against |
| the concept requirements. |
| </p> |
| <p> |
| A polygon is <span class="emphasis"><em>A polygon is a planar surface defined by one exterior |
| boundary and zero or more interior boundaries.</em></span> (<a href="http://portal.opengeospatial.org/files/?artifact_id=25355" target="_top">opengeospatial</a>). |
| </p> |
| <p> |
| So the definition of a Boost.Geometry polygon differs a bit from e.g. Wiki, |
| where a polygon does not have holes. A polygon of Boost.Geometry is a polygon |
| with or without holes. <span class="emphasis"><em>(A polygon without holes is a <span class="emphasis"><em>helper |
| geometry</em></span> within Boost.Geometry, and referred to as a ring.)</em></span> |
| </p> |
| <a name="geometry.reference.concepts.concept_polygon.concept_definition"></a><h6> |
| <a name="geometry.reference.concepts.concept_polygon.concept_definition-heading"></a> |
| <a class="link" href="concept_polygon.html#geometry.reference.concepts.concept_polygon.concept_definition">Concept |
| Definition</a> |
| </h6> |
| <p> |
| The Polygon Concept is defined as following: |
| </p> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">tag</span></code> |
| defining <code class="computeroutput"><span class="identifier">polygon_tag</span></code> |
| as type |
| </li> |
| <li class="listitem"> |
| there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">ring_type</span></code> |
| defining the type of its exterior ring and interior rings as type |
| </li> |
| <li class="listitem"> |
| this type defined by <code class="computeroutput"><span class="identifier">ring_type</span></code> |
| must fulfill the <a class="link" href="concept_ring.html" title="Ring Concept">Ring |
| Concept</a> |
| </li> |
| <li class="listitem"> |
| there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">interior_type</span></code> |
| defining the type of the collection of its interior rings as type; |
| this collection itself must fulfill a Boost.Range Random Access Range |
| Concept |
| </li> |
| <li class="listitem"> |
| there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">exterior_ring</span></code> |
| with two functions named <code class="computeroutput"><span class="identifier">get</span></code>, |
| returning the exterior ring, one being const, the other being non const |
| </li> |
| <li class="listitem"> |
| there must be a specialization of <code class="computeroutput"><span class="identifier">traits</span><span class="special">::</span><span class="identifier">interior_rings</span></code> |
| with two functions named <code class="computeroutput"><span class="identifier">get</span></code>, |
| returning the interior rings, one being const, the other being non |
| const |
| </li> |
| </ul></div> |
| <a name="geometry.reference.concepts.concept_polygon.available_models"></a><h6> |
| <a name="geometry.reference.concepts.concept_polygon.available_models-heading"></a> |
| <a class="link" href="concept_polygon.html#geometry.reference.concepts.concept_polygon.available_models">Available |
| Models</a> |
| </h6> |
| <div class="itemizedlist"><ul class="itemizedlist" type="disc"> |
| <li class="listitem"> |
| <a class="link" href="../models/model_polygon.html" title="model::polygon">polygon</a> |
| </li> |
| <li class="listitem"> |
| a Boost.Polygon polygon_with_holes_data (requires <code class="computeroutput"><span class="preprocessor">#include</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_polygon</span><span class="special">/</span><span class="identifier">polygon</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span></code>) |
| </li> |
| </ul></div> |
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| <td align="right"><div class="copyright-footer">Copyright © 2011 Barend Gehrels, Bruno Lalande, Mateusz Loskot<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 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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