1 <html xmlns:v="urn:schemas-microsoft-com:vml" xmlns:o="urn:schemas-microsoft-com:office:office" >
3 <title>Approximation of an arc with bezier</title>
4 <style type="text/css">
5 @import "../../../dojo/resources/dojo.css";
6 @import "../../../dijit/tests/css/dijitTests.css";
8 <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
10 The next line should include Microsoft's Silverligth.js, if you plan to use the silverlight backend
11 <script type="text/javascript" src="Silverlight.js"></script>
13 <script type="text/javascript" src="../../../dojo/dojo.js" djConfig="isDebug: true"></script>
14 <script type="text/javascript" src="../_base.js"></script>
15 <script type="text/javascript" src="../shape.js"></script>
16 <script type="text/javascript" src="../path.js"></script>
17 <script type="text/javascript" src="../arc.js"></script>
18 <!--<script type="text/javascript" src="../vml.js"></script>-->
19 <!--<script type="text/javascript" src="../svg.js"></script>-->
20 <!--<script type="text/javascript" src="../canvas.js"></script>-->
21 <!--<script type="text/javascript" src="../silverlight.js"></script>-->
22 <script type="text/javascript">
23 dojo.require("dojox.gfx");
25 makeShapes = function(){
26 var surface = dojox.gfx.createSurface("test", 500, 300);
27 var g = surface.createGroup();
29 // create a reference ellipse
35 var e = g.createEllipse({rx: rx, ry: ry}).setStroke({});
38 var alpha = dojox.gfx.matrix._degToRad(arcAngle) / 2; // half of our angle
39 var cosa = Math.cos(alpha);
40 var sina = Math.sin(alpha);
42 var p1 = {x: cosa, y: sina};
44 var p2 = {x: cosa + (4 / 3) * (1 - cosa), y: sina - (4 / 3) * cosa * (1 - cosa) / sina};
45 // 2nd control point (symmetric to the 1st one)
46 var p3 = {x: p2.x, y: -p2.y};
47 // end point (symmetric to the start point)
48 var p4 = {x: p1.x, y: -p1.y};
50 // rotate and scale poins as appropriate
51 var s = dojox.gfx.matrix.normalize([dojox.gfx.matrix.scale(e.shape.rx, e.shape.ry), dojox.gfx.matrix.rotateg(startAngle + arcAngle / 2)]);
52 p1 = dojox.gfx.matrix.multiplyPoint(s, p1);
53 p2 = dojox.gfx.matrix.multiplyPoint(s, p2);
54 p3 = dojox.gfx.matrix.multiplyPoint(s, p3);
55 p4 = dojox.gfx.matrix.multiplyPoint(s, p4);
56 // draw control trapezoid
57 var t = g.createPath().setStroke({color: "blue"});
63 t.moveTo((p1.x + p4.x) / 2, (p1.y + p4.y) / 2);
64 t.lineTo((p2.x + p3.x) / 2, (p2.y + p3.y) / 2);
65 t.moveTo((p1.x + p2.x) / 2, (p1.y + p2.y) / 2);
66 t.lineTo((p3.x + p4.x) / 2, (p3.y + p4.y) / 2);
68 var b = g.createPath().setStroke({color: "red"});
70 b.curveTo(p2.x, p2.y, p3.x, p3.y, p4.x, p4.y);
71 // move everything in a middle
72 g.setTransform([dojox.gfx.matrix.translate(250, 150), dojox.gfx.matrix.rotateg(axisAngle)]);
75 dojo.addOnLoad(makeShapes);
80 <h1>Approximation of an arc with bezier</h1>
81 <!--<p><button onclick="makeShapes();">Make</button></p>-->
82 <div id="test" style="width: 500px; height: 300px;"></div>
83 <p>That's all Folks!</p>