projects / ceph.git / blame
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|---|---|---|
| 7c673cae FG |
1 | <html> |
| 2 | ||
| 3 | <head> | |
| 4 | <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"> | |
| 5 | <title>Custom Polygon</title> | |
| 6 | </head> | |
| 7 | ||
| 8 | <body> | |
| 9 | ||
| 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 <boost/polygon/polygon.hpp><br> | |
| 18 | #include <cassert><br> | |
| 19 | #include <list><br> | |
| 20 | namespace gtl = boost::polygon;<br> | |
| 21 | using namespace boost::polygon::operators;<br><br> | |
| 22 | //first lets turn our polygon usage code into a generic<br> | |
| 23 | //function parameterized by polygon type<br> | |
| 24 | template <typename Polygon><br> | |
| 25 | void test_polygon() {<br> | |
| 26 | //lets construct a 10x10 rectangle shaped polygon<br> | |
| 27 | typedef typename gtl::polygon_traits<Polygon>::point_type Point;<br> | |
| 28 | Point pts[] = {gtl::construct<Point>(0, 0),<br> | |
| 29 | gtl::construct<Point>(10, 0),<br> | |
| 30 | gtl::construct<Point>(10, 10),<br> | |
| 31 | gtl::construct<Point>(0, 10) };<br> | |
| 32 | Polygon poly;<br> | |
| 33 | gtl::set_points(poly, pts, pts+4);<br> | |
| 34 | <br> | |
| 35 | //now lets see what we can do with this polygon<br> | |
| 36 | assert(gtl::area(poly) == 100.0f);<br> | |
| 37 | assert(gtl::contains(poly, gtl::construct<Point>(5, 5)));<br> | |
| 38 | assert(!gtl::contains(poly, gtl::construct<Point>(15, 5)));<br> | |
| 39 | gtl::rectangle_data<int> rect;<br> | |
| 40 | assert(gtl::extents(rect, poly)); //get bounding box of poly<br> | |
| 41 | assert(gtl::equivalence(rect, poly)); //hey, that's slick<br> | |
| 42 | assert(gtl::winding(poly) == gtl::COUNTERCLOCKWISE);<br> | |
| 43 | assert(gtl::perimeter(poly) == 40.0f);<br> | |
| 44 | <br> | |
| 45 | //add 5 to all coords of poly<br> | |
| 46 | gtl::convolve(poly, gtl::construct<Point>(5, 5));<br> | |
| 47 | //multiply all coords of poly by 2<br> | |
| 48 | gtl::scale_up(poly, 2);<br> | |
| 49 | gtl::set_points(rect, gtl::point_data<int>(10, 10),<br> | |
| 50 | gtl::point_data<int>(30, 30));<br> | |
| 51 | assert(gtl::equivalence(poly, rect));<br> | |
| 52 | }<br> | |
| 53 | <br> | |
| 54 | //Now lets declare our own polygon class<br> | |
| 55 | //Oops, we need a point class to support our polygon, lets borrow<br> | |
| 56 | //the CPoint example<br> | |
| 57 | struct CPoint {<br> | |
| 58 | int x;<br> | |
| 59 | int y;<br> | |
| 60 | };<br> | |
| 61 | <br> | |
| 62 | //we have to get CPoint working with boost polygon to make our polygon<br> | |
| 63 | //that uses CPoint working with boost polygon<br> | |
| 64 | namespace boost { namespace polygon {<br> | |
| 65 | template <><br> | |
| 66 | struct geometry_concept<CPoint> { typedef point_concept type; };<br> | |
| 67 | template <><br> | |
| 68 | struct point_traits<CPoint> {<br> | |
| 69 | typedef int coordinate_type;<br> | |
| 70 | <br> | |
| 71 | static inline coordinate_type get(const CPoint& point, <br> | |
| 72 | orientation_2d orient) {<br> | |
| 73 | if(orient == HORIZONTAL)<br> | |
| 74 | return point.x;<br> | |
| 75 | return point.y;<br> | |
| 76 | }<br> | |
| 77 | };<br> | |
| 78 | <br> | |
| 79 | template <><br> | |
| 80 | struct point_mutable_traits<CPoint> {<br> | |
| 81 | typedef int coordinate_type;<br> | |
| 82 | <br> | |
| 83 | static inline void set(CPoint& point, orientation_2d orient, | |
| 84 | int value) {<br> | |
| 85 | if(orient == HORIZONTAL)<br> | |
| 86 | point.x = value;<br> | |
| 87 | else<br> | |
| 88 | point.y = value;<br> | |
| 89 | }<br> | |
| 90 | static inline CPoint construct(int x_value, int y_value) {<br> | |
| 91 | CPoint retval;<br> | |
| 92 | retval.x = x_value;<br> | |
| 93 | retval.y = y_value; <br> | |
| 94 | return retval;<br> | |
| 95 | }<br> | |
| 96 | };<br> | |
| 97 | } }<br> | |
| 98 | <br> | |
| 99 | //I'm lazy and use the stl everywhere to avoid writing my own classes<br> | |
| 100 | //my toy polygon is a std::list<CPoint><br> | |
| 101 | typedef std::list<CPoint> CPolygon;<br> | |
| 102 | <br> | |
| 103 | //we need to specialize our polygon concept mapping in boost polygon<br> | |
| 104 | namespace boost { namespace polygon {<br> | |
| 105 | //first register CPolygon as a polygon_concept type<br> | |
| 106 | template <><br> | |
| 107 | struct geometry_concept<CPolygon>{ typedef polygon_concept type; };<br> | |
| 108 | <br> | |
| 109 | template <><br> | |
| 110 | struct polygon_traits<CPolygon> {<br> | |
| 111 | typedef int coordinate_type;<br> | |
| 112 | typedef CPolygon::const_iterator iterator_type;<br> | |
| 113 | typedef CPoint point_type;<br> | |
| 114 | <br> | |
| 115 | // Get the begin iterator<br> | |
| 116 | static inline iterator_type begin_points(const CPolygon& t) {<br> | |
| 117 | return t.begin();<br> | |
| 118 | }<br> | |
| 119 | <br> | |
| 120 | // Get the end iterator<br> | |
| 121 | static inline iterator_type end_points(const CPolygon& t) {<br> | |
| 122 | return t.end();<br> | |
| 123 | }<br> | |
| 124 | <br> | |
| 125 | // Get the number of sides of the polygon<br> | |
| 126 | static inline std::size_t size(const CPolygon& t) {<br> | |
| 127 | return t.size();<br> | |
| 128 | }<br> | |
| 129 | <br> | |
| 130 | // Get the winding direction of the polygon<br> | |
| 131 | static inline winding_direction winding(const CPolygon& t) {<br> | |
| 132 | return unknown_winding;<br> | |
| 133 | }<br> | |
| 134 | };<br> | |
| 135 | <br> | |
| 136 | template <><br> | |
| 137 | struct polygon_mutable_traits<CPolygon> {<br> | |
| 138 | //expects stl style iterators<br> | |
| 139 | template <typename iT><br> | |
| 140 | static inline CPolygon& set_points(CPolygon& t, <br> | |
| 141 | | |
| 142 | iT input_begin, iT input_end) {<br> | |
| 143 | t.clear();<br> | |
| 144 | t.insert(t.end(), input_begin, input_end);<br> | |
| 145 | return t;<br> | |
| 146 | }<br> | |
| 147 | <br> | |
| 148 | };<br> | |
| 149 | } }<br> | |
| 150 | <br> | |
| 151 | //now there's nothing left to do but test that our polygon<br> | |
| 152 | //works with library interfaces<br> | |
| 153 | int main() {<br> | |
| 154 | test_polygon<CPolygon>(); //woot!<br> | |
| 155 | return 0;<br> | |
| 156 | }<br> | |
| 157 | </font></p> | |
| 158 | ||
| 159 | ||
| 160 | <table class="docinfo" rules="none" frame="void" id="table1"> | |
| 161 | <colgroup> | |
| 162 | <col class="docinfo-name"><col class="docinfo-content"> | |
| 163 | </colgroup> | |
| 164 | <tbody vAlign="top"> | |
| 165 | <tr> | |
| 166 | <th class="docinfo-name">Copyright:</th> | |
| 167 |