Difference between revisions of "Bezier curves"

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Line 1: Line 1:
 
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.
<html><!--<form>
+
<html><form>
 
<input type="button" value="Add segment" onClick="addSegment();">
 
<input type="button" value="Add segment" onClick="addSegment();">
 
<input type="button" value="Remove last segment" onClick="removeSegment();">
 
<input type="button" value="Remove last segment" onClick="removeSegment();">
</form>--></html>
+
</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});
Line 27: Line 27:
  
 
var addSegment = function() {
 
var addSegment = function() {
 +
  brd.suspendUpdate();
 
   col = 'blue';  
 
   col = 'blue';  
 
   p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
 
   p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
Line 35: Line 36:
 
   p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
 
   p.push(brd.createElement('point',[Math.random()*8-4,Math.random()*8-4],
 
           {strokeColor:col,fillColor:col}));    // data point
 
           {strokeColor:col,fillColor:col}));    // data point
 +
  brd.unsuspendUpdate();
 
};
 
};
  

Revision as of 08:48, 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});