ceph/src/boost/libs/polygon/doc/gtl_polygon_set_usage.htm

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  10 <p><font face="Courier New">/*<br>
  11 Copyright 2008 Intel Corporation<br>
  12 <br>
  13 Use, modification and distribution are subject to the Boost Software License,<br>
  14 Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at<br>
  15 http://www.boost.org/LICENSE_1_0.txt).<br>
  16 */<br>
  17 #include &lt;boost/polygon/polygon.hpp&gt;<br>
  18 #include &lt;cassert&gt;<br>
  19 namespace gtl = boost::polygon;<br>
  20 using namespace boost::polygon::operators;<br><br>
  21 int main() {<br>&nbsp; &nbsp;
  22 //lets declare ourselves a polygon set<br>&nbsp; &nbsp;
  23 using namespace gtl; //because of operators<br>&nbsp; &nbsp;
  24 typedef std::vector&lt;polygon_data&lt;int&gt; &gt; PolygonSet;<br>&nbsp; &nbsp;
  25 PolygonSet ps;<br>&nbsp; &nbsp;
  26 <br>&nbsp; &nbsp;
  27 //lets put some data in<br>&nbsp; &nbsp;
  28 ps += rectangle_data&lt;int&gt;(0, 0, 10, 10);<br>&nbsp; &nbsp;
  29 <br>&nbsp; &nbsp;
  30 //now lets do something interesting<br>&nbsp; &nbsp;
  31 PolygonSet ps2;<br>&nbsp; &nbsp;
  32 ps2 += rectangle_data&lt;int&gt;(5, 5, 15, 15);<br>&nbsp; &nbsp;
  33 PolygonSet ps3;<br>&nbsp; &nbsp;
  34 assign(ps3, ps * ps2); //woah, I just felt the room flex around me<br>&nbsp; &nbsp;
  35 PolygonSet ps4;<br>&nbsp; &nbsp;
  36 ps4 += ps + ps2;<br>&nbsp; &nbsp;
  37 <br>&nbsp; &nbsp;
  38 //assert that area of result is equal to sum of areas<br>&nbsp; &nbsp;
  39 //of input geometry minus the area of overlap between inputs<br>&nbsp; &nbsp;
  40 assert(area(ps4) == area(ps) + area(ps2) - area(ps3));<br>&nbsp; &nbsp;
  41 <br>&nbsp; &nbsp;
  42 //I don't even see the code anymore, all<br>&nbsp; &nbsp;
  43 //I see is bounding box...interval...triangle<br>&nbsp; &nbsp;
  44 <br>&nbsp; &nbsp;
  45 //lets try that again in slow motion shall we?<br>&nbsp;&nbsp;&nbsp;
  46 assert(equivalence((ps + ps2) - (ps * ps2), ps ^ ps2));<br>
  47 <br>
  48 &nbsp;&nbsp;&nbsp; //hmm, subtracting the intersection from the union<br>
  49 &nbsp;&nbsp;&nbsp; //is equivalent to the xor, all this in one line of code,<br>
  50 &nbsp;&nbsp;&nbsp; //now we're programming in bullet time<br>
  51 &nbsp;&nbsp;&nbsp; //(by the way, xor is implemented as one pass, not
  52 composition)&nbsp; <br>&nbsp; &nbsp;
  53 <br>&nbsp; &nbsp;
  54 //just for fun<br>&nbsp; &nbsp;
  55 rectangle_data&lt;int&gt; rect;<br>&nbsp; &nbsp;
  56 assert(extents(rect, ps ^ ps2));<br>&nbsp; &nbsp;
  57 assert(area(rect) == 225);<br>&nbsp; &nbsp;
  58 assert(area(rect ^ (ps ^ ps2)) == area(rect) - area(ps ^ ps2)); <br>&nbsp; &nbsp;
  59 return 0;<br>}<br>&nbsp; &nbsp;
  60 <br>//Now you know how to use the polygon set concept with library polygons<br>&nbsp; &nbsp;
  61 &nbsp;</font></p>
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  66                 <col class="docinfo-name"><col class="docinfo-content">
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  70                         <th class="docinfo-name">Copyright:</th>
  71                         <td>Copyright © Intel Corporation 2008-2010.</td>
  72                 </tr>
  73                 <tr class="field">
  74                         <th class="docinfo-name">License:</th>
  75                         <td class="field-body">Distributed under the Boost Software License,
  76                         Version 1.0. (See accompanying file <tt class="literal">
  77                         <span class="pre">LICENSE_1_0.txt</span></tt> or copy at
  78                         <a class="reference" target="_top" href="http://www.boost.org/LICENSE_1_0.txt">
  79                         http://www.boost.org/LICENSE_1_0.txt</a>)</td>
  80                 </tr>
  81 </table>
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