414f72bea3
[SVN r83804]
296 lines
15 KiB
HTML
296 lines
15 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
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<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
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<head>
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<!--
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Copyright 2009-2010 Intel Corporation
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license banner
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-->
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<title>Boost Polygon Library: Main Page</title>
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<meta http-equiv="content-type" content="text/html;charset=ISO-8859-1" />
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<!-- <link type="text/css" rel="stylesheet" href="adobe_source.css"> -->
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</head>
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<body>
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<table style="margin: 0pt; padding: 0pt; width: 100%;" border="0"
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cellpadding="0" cellspacing="0">
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<tbody>
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<tr>
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<td style="background-color: rgb(238, 238, 238);" nowrap="1"
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valign="top">
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<div style="padding: 5px;" align="center"> <img
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src="images/boost.png" border="0" height="86" width="277" /><a
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title="www.boost.org home page" href="http://www.boost.org/"
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tabindex="2" style="border: medium none ;"> </a> </div>
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<div style="margin: 5px;">
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<h3 class="navbar">Contents</h3>
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<ul>
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<li>Boost.Polygon Main Page</li>
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<li><a href="gtl_design_overview.htm">Design Overview</a></li>
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<li><a href="gtl_isotropy.htm">Isotropy</a></li>
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<li><a href="gtl_coordinate_concept.htm">Coordinate Concept</a></li>
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<li><a href="gtl_interval_concept.htm">Interval Concept</a></li>
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<li><a href="gtl_point_concept.htm">Point Concept</a></li>
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<li><a href="gtl_segment_concept.htm">Segment Concept</a></li>
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<li><a href="gtl_rectangle_concept.htm">Rectangle Concept</a></li>
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<li><a href="gtl_polygon_90_concept.htm">Polygon 90 Concept</a></li>
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<li><a href="gtl_polygon_90_with_holes_concept.htm">Polygon 90
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With Holes Concept</a></li>
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<li><a href="gtl_polygon_45_concept.htm">Polygon 45 Concept</a></li>
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<li><a href="gtl_polygon_45_with_holes_concept.htm">Polygon 45
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With Holes Concept</a></li>
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<li><a href="gtl_polygon_concept.htm">Polygon Concept</a></li>
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<li><a href="gtl_polygon_with_holes_concept.htm">Polygon With
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Holes Concept</a></li>
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<li><a href="gtl_polygon_90_set_concept.htm">Polygon 90 Set
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Concept</a></li>
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<li><a href="gtl_polygon_45_set_concept.htm">Polygon 45 Set
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Concept</a></li>
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<li><a href="gtl_polygon_set_concept.htm">Polygon Set Concept</a></li>
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<li><a href="gtl_connectivity_extraction_90.htm">Connectivity
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Extraction 90</a></li>
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<li><a href="gtl_connectivity_extraction_45.htm">Connectivity
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Extraction 45</a></li>
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<li><a href="gtl_connectivity_extraction.htm">Connectivity
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Extraction</a></li>
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<li><a href="gtl_property_merge_90.htm">Property Merge 90</a></li>
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<li><a href="gtl_property_merge_45.htm">Property Merge 45</a></li>
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<li><a href="gtl_property_merge.htm">Property Merge</a></li>
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<li><a href="voronoi_main.htm">Voronoi Main Page<br />
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</a></li>
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<li><a href="voronoi_benchmark.htm">Voronoi Benchmark</a><br />
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</li>
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<li><a href="voronoi_builder.htm">Voronoi Builder</a></li>
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<li><a href="voronoi_diagram.htm">Voronoi Diagram</a></li>
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</ul>
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<h3 class="navbar">Other Resources</h3>
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<ul>
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<li><a href="GTL_boostcon2009.pdf">GTL Boostcon 2009 Paper</a></li>
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<li><a href="GTL_boostcon_draft03.pdf">GTL Boostcon 2009
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Presentation</a></li>
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<li><a href="analysis.htm">Performance Analysis</a></li>
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<li><a href="gtl_tutorial.htm">Layout Versus Schematic Tutorial</a></li>
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<li><a href="gtl_minkowski_tutorial.htm">Minkowski Sum Tutorial</a></li>
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<li><a href="voronoi_basic_tutorial.htm">Voronoi Basic Tutorial</a></li>
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<li><a href="voronoi_advanced_tutorial.htm">Voronoi Advanced
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Tutorial</a></li>
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</ul>
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</div>
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<h3 class="navbar">Polygon Sponsor</h3>
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<div style="padding: 5px;" align="center"> <img
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src="images/intlogo.gif" border="0" height="51" width="127" /><a
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title="www.adobe.com home page" href="http://www.adobe.com/"
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tabindex="2" style="border: medium none ;"> </a> </div>
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</td>
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<td
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style="padding-left: 10px; padding-right: 10px; padding-bottom: 10px;"
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valign="top" width="100%">
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<!-- End Header --><br />
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<p>
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</p>
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<h1>THE BOOST.POLYGON LIBRARY</h1>
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<p>The Boost.Polygon library provides algorithms focused on
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manipulating planar polygon geometry data. Specific algorithms
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provided are the polygon set operations (intersection, union,
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difference, disjoint-union) and related algorithms such as polygon
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connectivity graph extraction, offsetting and map-overlay. An
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example of the disjoint-union (XOR) of figure a and figure b is shown
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below in figure c. These so-called Boolean algorithms are of
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significant interest in GIS (Geospatial Information Systems), VLSI CAD
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as well all other fields of CAD, and many more application areas, and
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providing them is the primary focus of this library. The
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Boost.Polygon library is not intended to cover all of computational
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geometry in its scope, and provides a set of capabilities for working
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with coordinates, points, intervals and rectangles that are needed to
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support implementing and interacting with polygon data structures and
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algorithms. </p>
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<img src="images/hand.png" border="0" height="277" width="837" />
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<p>One of the important features of the library is the
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implementation of
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the generic sweepline algorithm to construct Voronoi diagrams of points
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and linear segments in 2D (developed
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as part of the GSoC 2010 program). Voronoi diagram data structure has
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applications in image segmentation, optical character recognition,
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nearest neighbor queries execution. It is closely related with the
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other
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computational geometry concepts: Delaunay triangulation, medial axis,
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straight skeleton, the largest empty circle. The Boost.Polygon library
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provides interface to construct Voronoi diagram of points figure a and
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line segments figure b (the last could be used to discretize any
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two-dimensional curve). Figure c contains the example of the medial
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axis of the
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non-convex polygon. The implementation <a href="voronoi_benchmark.htm">outperforms</a>
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most of the known
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commercial and non-commercial libraries in both efficiency and
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numerical robustness aspects. You may find more details on the topic at
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the <a href="voronoi_main.htm">Voronoi main page</a>.<br />
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</p>
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<p><img src="images/voronoi.png" border="0" height="300"
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width="900" /></p>
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<p>The coordinate data type is a template parameter of all data
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types
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and algorithms provided by the library, and is expected to be integral.
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Floating point coordinate data types are not supported by the
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algorithms implemented in the library due to the fact that the
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achieving floating point robustness implies a different set of
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algorithms and generally platform specific assumptions about floating
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point representations.
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For additional detailed discussion of the library and its
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implementation including benchmark comparisons with other open source
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alternatives please see the <a href="GTL_boostcon2009.pdf">paper</a>
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and
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<a href="GTL_boostcon_draft03.pdf">presentation</a> from
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<a href="http://www.boostcon.com/home">boostcon</a> 2009 as well
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as a detailed
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<a href="analysis.htm">analysis</a> of the runtime complexity of
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the library's core algorithms. </p>
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<p>The design philosophy behind the polygon library was to create
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an API for invoking the library algorithms it provides on user geometry
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data types that is maximally intuitive, minimally error-prone and easy
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to integrate into pre-existing applications. C++-concepts based
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template meta-programming combined with generic operator overloading
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meets these design goals without sacrificing the runtime or memory
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efficiency of the underlying algorithms. The API is intended to
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demonstrate what could be achieved with ease by a C++-concepts based
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library interface, but is implemented based on current language
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features. This API makes the following code snippet that operates
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on non-library geometry types possible:</p>
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<p:colorscheme
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colors="#ffffff,#000000,#808080,#000000,#bbe0e3,#333399,#009999,#99cc00">
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</p:colorscheme>
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<div v:shape="_x0000_s1026" class="O">
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<div style="text-align: justify;"> <nobr> <span
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style="font-family: Courier New;"> void foo(list<CPolygon>&
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result, const list<CPolygon>& a, </span></nobr><br />
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<span style="font-family: Courier New;">
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</span><nobr> <span style="font-family: Courier New;"> const
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list<CPolygon>& b, int deflateValue) { </span></nobr></div>
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<div style="text-align: justify;"> <nobr><span
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style="font-family: Courier New;">
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CBoundingBox domainExtent; </span></nobr></div>
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<div style="text-align: justify;"> <nobr> <span
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style="font-family: Courier New;"> <span style=""> </span>
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using namespace boost::polygon::operators; </span></nobr></div>
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<div style="text-align: justify;"> <nobr> <span
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style="font-family: Courier New;"> <span style=""> </span>
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boost::polygon::extents(domainExtent, a); </span></nobr></div>
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<div style="text-align: justify;"> <nobr> <span
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style="font-family: Courier New;"> <span style="">
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</span>result += (b & domainExtent) ^ (a - deflateValue); </span></nobr></div>
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<div style="text-align: justify;"> <nobr> <span
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style="font-family: Courier New;"> }</span></nobr></div>
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</div>
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<p>In the code snippet above the hypothetical polygon type
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CPolygon has been mapped to the library polygon concept and is used
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with library APIs to clip polygon list <i>b</i> against the bounding
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box of polygon list <i>a</i> and apply the disjoint-union of that with
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polygon list <i>a</i> deflated by some integer amount. The end
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result is accumulated into a list of polygons with a union
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operation. It is considerably more typing to describe this usage
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of the API than to code it, and the description is not much clearer
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than the code itself. A picture is worth a thousand words.</p>
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<p><img src="images/foo.PNG" border="0" height="371" width="432" /></p>
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<p>In Boost.Polygon operations such as those shown above are free
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functions named for what they do, or are overloads of C++ operators
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that make it easy to infer from reading the code what to expect.
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Operators are contained in the namespace <font face="Courier New">boost::polygon::operators</font>
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so that they can be used outside the <font face="Courier New">boost::polygon</font>
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namespace without bringing in the entire <font face="Courier New">boost::polygon</font>
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namespace. Following the principle of least astonishment, the
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inferred behavior should generally match the actual behavior.
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Conventions such as argument ordering (output arguments come first) and
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consistently applying the same semantics across different functions
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(accumulate) reduces the learning curve for new users while reducing
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the need to memorize semantics and argument ordering of many different
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functions for advanced users.</p>
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<p>While the internal library code that implements this API is
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usually complex and cryptic due to heavy use of template
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meta-programming, the application of the library API in user code is
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usually simple and clear because it is free of any extraneous
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syntax. The one exception to this is the mapping of user types to
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library concepts, which necessitates that the user perform some simple
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template programming and understand some of the internals of how the
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library concept type system works. The examples below should aid
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the user in performing these programming tasks.</p>
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<ul>
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<li>Example files:
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<ul>
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<li><a href="gtl_point_usage.htm">point_usage.cpp</a> Using
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the library provided point data type and functions</li>
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<li><a href="gtl_custom_point.htm">custom_point.cpp</a>
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Mapping a user defined point class to the library point_concept</li>
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<li><a href="gtl_polygon_usage.htm">polygon_usage.cpp</a>
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Using the library provided polygon data types and functions</li>
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<li><a href="gtl_custom_polygon.htm">custom_polygon.cpp</a>
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Mapping a user defined polygon class to the library polygon_concept</li>
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<li><a href="gtl_polygon_set_usage.htm">polygon_set_usage.cpp</a>
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Using the library provided polygon set data types and functions</li>
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<li><a href="gtl_custom_polygon_set.htm">custom_polygon_set.cpp</a>
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Mapping a user defined class to the library polygon_set_concept</li>
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<li><a href="gtl_connectivity_extraction_usage.htm">connectivity_extraction_usage.cpp</a>
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Using the connectivity extraction algorithm to build a connectivity
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graph on polygons</li>
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<li><a href="gtl_property_merge_usage.htm">property_merge_usage.cpp</a>
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Using the n-layer map-overlay algorithm on polygon data</li>
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</ul>
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</li>
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<li>Tutorials:
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<ul>
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<li><a href="gtl_tutorial.htm">Layout Versus Schematic</a>
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Learn how to apply Boost.Polygon capabilities to implement a simplified
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circuit extraction application</li>
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<li><a href="gtl_minkowski_tutorial.htm">Minkowski Sum</a>
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Learn how to apply Boost.Polygon capabilities to implement Minkowski
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sum of polygon sets</li>
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<li><a href="voronoi_basic_tutorial.htm">Voronoi Basic
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Tutorial</a> Learn how to construct, traverse, visualize, associate
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data with Voronoi diagrams without digging into the library details.</li>
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<li><a href="voronoi_advanced_tutorial.htm">Voronoi
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Advanced Tutorial</a> Learn how to configure the Voronoi builder and
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Voronoi diagram data structure with the user provided coordinate types.
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</li>
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</ul>
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</li>
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</ul>
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<p>We would like to thank: Thomas Klimpel, Frank Mori Hess,
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Barend Gehrels, Andreas Fabri, Jeffrey Hellrung, Tim Keitt, Markus
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Werle, Paul A. Bristow, Robert Stewart, Mathias Gaunard, Michael
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Fawcett, Steven Watanabe, Joachim Faulhaber, John Bytheway, Sebastian
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Redl, Mika Heiskanen, John Phillips, Kai Benndorf, Hartmut Kaiser,
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Arash Partow, Maurizio Vitale, Brandon Kohn, David Abrahams, Gordon
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Woodhull, Daniel James, John Maddock, Tom Brinkman, Bo Persson, Mateusz
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Loskot, Christian Henning, Jean-Sebastien Stoezel, for providing
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feedback and or formal review of the library as part of the boost
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submission process and Fernando Cacciola for graciously serving as
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review manager.</p>
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</td>
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</tr>
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<tr>
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<td style="background-color: rgb(238, 238, 238);" nowrap="1"
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valign="top"> </td>
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<td
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style="padding-left: 10px; padding-right: 10px; padding-bottom: 10px;"
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valign="top" width="100%">
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<table class="docinfo" id="table2" frame="void" rules="none">
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<colgroup> <col class="docinfo-name" /><col
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class="docinfo-content" /> </colgroup> <tbody valign="top">
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<tr>
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<th class="docinfo-name">Copyright:</th>
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<td>Copyright <20> Intel Corporation 2008-2010.</td>
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</tr>
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<tr class="field">
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<th class="docinfo-name">License:</th>
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<td class="field-body">Distributed under the Boost Software
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License, Version 1.0. (See accompanying file <tt class="literal"> <span
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class="pre">LICENSE_1_0.txt</span></tt> or copy at <a
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class="reference" target="_top"
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href="http://www.boost.org/LICENSE_1_0.txt">
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http://www.boost.org/LICENSE_1_0.txt</a>)</td>
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</tr>
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</tbody>
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</table>
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</td>
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</tr>
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</tbody>
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</table>
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</body>
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</html>
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