Spirograph: Difference between revisions

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<jsxgraph width="600" height="600">
<jsxgraph width="600" height="600">
var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-5,5,5,-5], kkeepaspectratio:true});
var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-5,5,5,-5], keepaspectratio:true});
var R = 2.0;
var R = 2.0;
var r = brd.create('slider',[[-3,4],[3,4],[-5,1,5]],{name:'r'});
var r = brd.create('slider',[[-3,4],[3,4],[-5,1,5]],{name:'r'});
Line 7: Line 7:
var c = brd.create('curve',[
var c = brd.create('curve',[
     function(t){  
     function(t){  
         var r1 = r.Value();  
         var r1 = Math.round(100.0*r.Value())/100.0;
         return (R-r1)*Math.cos(r1/R*t)+a.Value()*Math.cos((1-r1/R)*t);  
        var a1 = Math.round(100.0*a.Value())/100.0;  
         return (R-r1)*Math.cos(r1/R*t)+a1*Math.cos((1-r1/R)*t);  
     },
     },
     function(t){  
     function(t){  
         var r1 = r.Value();  
         var r1 = Math.round(100.0*r.Value())/100.0;
         return (R-r1)*Math.sin(r1/R*t)+a.Value()*Math.sin((1-r1/R)*t);  
        var a1 = Math.round(100.0*a.Value())/100.0;  
         return (R-r1)*Math.sin(r1/R*t)+a1*Math.sin((1-r1/R)*t);  
     },  
     },  
     -40*Math.PI,40*Math.PI
     -40*Math.PI,40*Math.PI
     ], {strokeWidth:3, strokeColor:'#3355ff', strokeOpacity:0.7});
     ], {strokeWidth:3, strokeColor:'#3355ff', strokeOpacity:0.7});
</jsxgraph>
</jsxgraph>
===The underlying JavaScript code===
<source lang="javascript">
var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-5,5,5,-5], keepaspectratio:true});
var R = 2.0;
var r = brd.create('slider',[[-3,4],[3,4],[-5,1,5]],{name:'r'});
var a = brd.create('slider',[[-3,3],[3,3],[-5,1,5]],{name:'a'});
var c = brd.create('curve',[
    function(t){
        var r1 = Math.round(100.0*r.Value())/100.0;
        var a1 = Math.round(100.0*a.Value())/100.0;
        return (R-r1)*Math.cos(r1/R*t)+a1*Math.cos((1-r1/R)*t);
    },
    function(t){
        var r1 = Math.round(100.0*r.Value())/100.0;
        var a1 = Math.round(100.0*a.Value())/100.0;
        return (R-r1)*Math.sin(r1/R*t)+a1*Math.sin((1-r1/R)*t);
    },
    -40*Math.PI,40*Math.PI
    ], {strokeWidth:3, strokeColor:'#3355ff', strokeOpacity:0.7});
</source>
[[Category:Examples]]
[[Category:Curves]]

Latest revision as of 19:39, 19 July 2010

The underlying JavaScript code

var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-5,5,5,-5], keepaspectratio:true});
var R = 2.0;
var r = brd.create('slider',[[-3,4],[3,4],[-5,1,5]],{name:'r'});
var a = brd.create('slider',[[-3,3],[3,3],[-5,1,5]],{name:'a'});

var c = brd.create('curve',[
     function(t){ 
        var r1 = Math.round(100.0*r.Value())/100.0; 
        var a1 = Math.round(100.0*a.Value())/100.0; 
        return (R-r1)*Math.cos(r1/R*t)+a1*Math.cos((1-r1/R)*t); 
     },
     function(t){ 
        var r1 = Math.round(100.0*r.Value())/100.0; 
        var a1 = Math.round(100.0*a.Value())/100.0; 
        return (R-r1)*Math.sin(r1/R*t)+a1*Math.sin((1-r1/R)*t); 
     }, 
     -40*Math.PI,40*Math.PI
     ], {strokeWidth:3, strokeColor:'#3355ff', strokeOpacity:0.7});