Bezier curves: Difference between revisions
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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. | ||
<html> | <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 | </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 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], | ||
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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 06:48, 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});
