Bearing: Difference between revisions

From JSXGraph Wiki
Line 49: Line 49:
<html>
<html>
<form>
<form>
<input type="text" id="degrees">
<input type="text" id="degrees2">
<input type="button" value="set direction" onclick="setDirection()">
<input type="button" value="set direction" onclick="setDirection()">
</form>
</form>
Line 60: Line 60:
var a = brd2.create('arc',[p1,p2,p3]);
var a = brd2.create('arc',[p1,p2,p3]);


var q = brd2.create('glider',[-1,0.5,a],{name:'drag me'}); // global variable
var q = brd2.create('glider',[0.5,0.5,a],{name:'drag me'}); // global variable
brd2.addHook(function(){
brd2.addHook(function(){
                   document.getElementById('degrees2').value = (Math.atan2(q.Y(),q.X())*180/Math.PI).toFixed(0);
                   document.getElementById('degrees2').value = (Math.atan2(q.Y(),q.X())*180/Math.PI).toFixed(0);

Revision as of 16:30, 16 June 2010

The underlying JavaScript code

<form>
<input type="text" id="degrees">
<input type="button" value="set direction" onclick="setDirection()">
</form>
var brd = JXG.JSXGraph.initBoard('jxgbox',{axis:true,boundingbox:[-2,1.5,2,-1.5],keepaspectratio:true});
var c = brd.create('circle',[[0,0],1]);
var p = brd.create('glider',[-1,0.5,c],{name:'drag me'}); // global variable
brd.addHook(function(){
                  document.getElementById('degrees').value = (Math.atan2(p.Y(),p.X())*180/Math.PI).toFixed(0);
            });

var setDirection = function() {
   var phi = 1*document.getElementById('degrees').value*Math.PI/180.0;
   var r = c.Radius();
   p.moveTo([r*Math.cos(phi),r*Math.sin(phi)]);

}

Version 2