Difference between revisions of "Bezier curves"

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The red points are connected by a cubic Bezier curve. The blue points are the control points.
 
The red points are connected by a cubic Bezier curve. The blue points are the control points.
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<html><form>
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<input type="button" value="Add segment" onClick="addSegment();">
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<input type="button" value="Remove last segment" onClick="removeSegment();">
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</form></html>
 
<jsxgraph width="600" height="600">
 
<jsxgraph width="600" height="600">
 
var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-4,4,4,-4],keepaspectratio:true,axis:true});
 
var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-4,4,4,-4],keepaspectratio:true,axis:true});
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var c = brd.createElement('curve', JXG.Math.Numerics.bezier(p), {strokecolor:'blue', strokeOpacity:0.6, strokeWidth:5});  
 
var c = brd.createElement('curve', JXG.Math.Numerics.bezier(p), {strokecolor:'blue', strokeOpacity:0.6, strokeWidth:5});  
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 +
var addSegment = function() {
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col = 'blue';
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p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
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          {strokeColor:col,fillColor:col})); // control point
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p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
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          {strokeColor:col,fillColor:col}));  // control point
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col = 'red';
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p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
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          {strokeColor:col,fillColor:col}));    // data point
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};
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</jsxgraph>
 
</jsxgraph>
  

Revision as of 08:08, 29 September 2009

The red points are connected by a cubic Bezier curve. The blue points are the control points.

The underlying JavaScript code

var brd = JXG.JSXGraph.initBoard('jxgbox',{boundingbox:[-4,4,4,-4],keepaspectratio:true,axis:true});

var p = [];

col = 'red'; 
p.push(brd.createElement('point',[2,1],{strokeColor:col,fillColor:col}));        // data point
col = 'blue'; 
p.push(brd.createElement('point',[0.75,2.5],{strokeColor:col,fillColor:col}));   // control point
p.push(brd.createElement('point',[-0.3,0.3],{strokeColor:col,fillColor:col}));   // control point

col = 'red'; 
p.push(brd.createElement('point',[-3,1],{strokeColor:col,fillColor:col}));       // data point
col = 'blue'; 
p.push(brd.createElement('point',[-0.75,-2.5],{strokeColor:col,fillColor:col})); // control point
p.push(brd.createElement('point',[1.5,-2.8],{strokeColor:col,fillColor:col}));   // control point

col = 'red'; 
p.push(brd.createElement('point',[2,-0.5],{strokeColor:col,fillColor:col}));     // data point

var c = brd.createElement('curve', JXG.Math.Numerics.bezier(p), {strokecolor:'blue', strokeOpacity:0.6, strokeWidth:5});