projects / ceph.git / blame
| Commit | Line | Data |
|---|---|---|
| 7c673cae FG |
1 | <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> |
| 2 | <html><head> | |
| 3 | ||
| 4 | ||
| 5 | <meta http-equiv="Content-Type" content="text/html; charset=windows-1252"><title>Custom Point</title></head><body> | |
| 6 | ||
| 7 | <p><font face="Courier New">/*<br> | |
| 8 | Copyright 2008 Intel Corporation<br> | |
| 9 | <br> | |
| 10 | Use, modification and distribution are subject to the Boost Software License,<br> | |
| 11 | Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at<br> | |
| 12 | http://www.boost.org/LICENSE_1_0.txt).<br> | |
| 13 | */<br> | |
| 14 | #include <boost/polygon/polygon.hpp><br> | |
| 15 | #include <cassert><br> | |
| 16 | namespace gtl = boost::polygon;<br> | |
| 17 | using namespace boost::polygon::operators;<br><br> | |
| 18 | //lets make the body of main from point_usage.cpp<br>//a generic function parameterized by point type<br>template <typename Point><br>void test_point() {<br> | |
| 19 | //constructing a gtl point<br> | |
| 20 | int x = 10;<br> | |
| 21 | int y = 20;<br> | |
| 22 | //Point pt(x, y);<br> | |
| 23 | Point pt = gtl::construct<Point>(x, y);<br> | |
| 24 | assert(gtl::x(pt) == 10);<br> | |
| 25 | assert(gtl::y(pt) == 20);<br> | |
| 26 | <br> | |
| 27 | //a quick primer in isotropic point access<br> | |
| 28 | typedef gtl::orientation_2d O;<br> | |
| 29 | using gtl::HORIZONTAL;<br> | |
| 30 | using gtl::VERTICAL;<br> | |
| 31 | O o = HORIZONTAL;<br> | |
| 32 | assert(gtl::x(pt) == gtl::get(pt, o));<br> | |
| 33 | <br> | |
| 34 | o = o.get_perpendicular();<br> | |
| 35 | assert(o == VERTICAL);<br> | |
| 36 | assert(gtl::y(pt) == gtl::get(pt, o));<br> | |
| 37 | <br> | |
| 38 | gtl::set(pt, o, 30);<br> | |
| 39 | assert(gtl::y(pt) == 30);<br> | |
| 40 | <br> | |
| 41 | //using some of the library functions<br> | |
| 42 | //Point pt2(10, 30);<br> | |
| 43 | Point pt2 = gtl::construct<Point>(10, 30);<br> | |
| 44 | assert(gtl::equivalence(pt, pt2));<br> | |
| 45 | <br> | |
| 46 | gtl::transformation<int> tr(gtl::axis_transformation::SWAP_XY);<br> | |
| 47 | gtl::transform(pt, tr);<br> | |
| 48 | assert(gtl::equivalence(pt, gtl::construct<Point>(30, 10)));<br> | |
| 49 | <br> | |
| 50 | gtl::transformation<int> tr2 = tr.inverse();<br> | |
| 51 | assert(tr == tr2); //SWAP_XY is its own inverse transform<br> | |
| 52 | <br> | |
| 53 | gtl::transform(pt, tr2);<br> | |
| 54 | assert(gtl::equivalence(pt, pt2)); //the two points are equal again<br> | |
| 55 | <br> | |
| 56 | gtl::move(pt, o, 10); //move pt 10 units in y<br> | |
| 57 | assert(gtl::euclidean_distance(pt, pt2) == 10.0f);<br> | |
| 58 | <br> | |
| 59 | gtl::move(pt, o.get_perpendicular(), 10); //move pt 10 units in x<br> | |
| 60 | assert(gtl::manhattan_distance(pt, pt2) == 20);<br>}<br> | |
| 61 | <br>//Now lets declare our own point type<br>//Bjarne says that if a class doesn't maintain an<br>//invariant just use a struct.<br>struct CPoint {<br> | |
| 62 | int x;<br> | |
| 63 | int y;<br>};<br> | |
| 64 | <br>//There, nice a simple...but wait, it doesn't do anything<br>//how do we use it to do all the things a point needs to do?<br> | |
| 65 | <br> | |
| 66 | <br>//First we register it as a point with boost polygon<br>namespace boost { | |
| 67 | namespace polygon {<br> | |
| 68 | template <><br> | |
| 69 | struct geometry_concept<CPoint> { typedef point_concept type; };<br> <br> | |
| 70 | <br> //Then we specialize the gtl point traits for our point type<br> | |
| 71 | template <><br> | |
| 72 | struct point_traits<CPoint> {<br> | |
| 73 | | |
| 74 | typedef int coordinate_type;<br> | |
| 75 | <br> | |
| 76 | | |
| 77 | static inline coordinate_type get(const CPoint& point, <br> | |
| 78 | | |
| 79 | orientation_2d orient) {<br> | |
| 80 | | |
| 81 | | |
| 82 | if(orient == HORIZONTAL)<br> | |
| 83 | | |
| 84 | | |
| 85 | | |
| 86 | return point.x;<br> | |
| 87 | | |
| 88 | | |
| 89 | return point.y;<br> | |
| 90 | | |
| 91 | }<br> | |
| 92 | };<br> | |
| 93 | <br> | |
| 94 | template <><br> | |
| 95 | struct point_mutable_traits<CPoint> {<br> | |
| 96 | typedef int coordinate_type;<br> | |
| 97 | <br> | |
| 98 | </font></p> | |
| 99 | <p><font face="Courier New"> | |
| 100 | | |
| 101 | static inline void set(CPoint& point, orientation_2d orient, int value) {<br> | |
| 102 | | |
| 103 | | |
| 104 | if(orient == HORIZONTAL)<br> | |
| 105 | | |
| 106 | | |
| 107 | | |
| 108 | point.x = value;<br> | |
| 109 | | |
| 110 | | |
| 111 | else<br> | |
| 112 | | |
| 113 | | |
| 114 | point.y = value;<br> | |
| 115 | | |
| 116 | }<br> | |
| 117 | | |
| 118 | static inline CPoint construct(int x_value, int y_value) {<br> | |
| 119 | | |
| 120 | | |
| 121 | CPoint retval;<br> | |
| 122 | | |
| 123 | | |
| 124 | retval.x = x_value;<br> | |
| 125 | | |
| 126 | | |
| 127 | retval.y = y_value; <br> | |
| 128 | | |
| 129 | | |
| 130 | return retval;<br> | |
| 131 | | |
| 132 | }<br> | |
| 133 | };<br>} }<br> | |
| 134 | <br>//Now lets see if the CPoint works with the library functions<br>int main() {<br> | |
| 135 | test_point<CPoint>(); //yay! All your testing is done for you.<br> | |
| 136 | return 0;<br>}<br> | |
| 137 | <br>//Now you know how to map a user type to the library point concept<br>//and how to write a generic function parameterized by point type<br>//using the library interfaces to access it.<br> | |
| 138 | </font></p> | |
| 139 | ||
| 140 | ||
| 141 | ||
| 142 | <table class="docinfo" id="table1" frame="void" rules="none"> | |
| 143 | <colgroup> | |
| 144 | <col class="docinfo-name"><col class="docinfo-content"> | |
| 145 | </colgroup> | |
| 146 | <tbody valign="top"> | |
| 147 | <tr> | |
| 148 | <th class="docinfo-name">Copyright:</th> | |
| 149 |