HTML 5：绘制旋转的太极图

时间：2023-03-09 13:32:34
HTML 5：绘制旋转的太极图

HTML 5：绘制旋转的太极图

HTML：

<!DOCTYPE>

<html>

<head>

    <meta charset="utf-8" />

    <title>Canvas绘制旋转太极</title>

</head>

<body>

    <canvas id="face" width="200" height="200"></canvas>

</body>

</html>

JavaScript:

var canvas = document.getElementById("face");

var cxt = canvas.getContext('2d');

var r = 100;   //半径

var pointX = 0;  //圆心x坐标

var pointY = 0; //圆心y坐标

 // 绘制扇形填充

 function pie (g,radius,startAngle,endAngle,color,x,y)

 {

     g.fillStyle = color;

     g.beginPath();

     g.arc(x,y,radius,startAngle,endAngle,true);

     g.closePath();

     g.fill();

 }

 var q = 0;

 function redrawTaiji()

 {

     // 保存状态

     cxt.save();

     // 清理图像

     cxt.clearRect(0,0,canvas.width,canvas.height);

     cxt.translate(100,100);

     q += Math.PI / 6;

     cxt.rotate(q);

     cxt.beginPath();

     // 绘制两个最大圆

     pie(cxt,r,3/4*Math.PI*2,5/4*Math.PI*2,"#FF072A",pointX,pointY);

     pie(cxt,r,1/4*Math.PI*2,3/4*Math.PI*2,"#195089",pointX,pointY);

     // 绘制两个中圆

     pie(cxt,r/2,0,Math.PI*2,"#FF072A",pointX,pointY+r/2);

     pie(cxt,r/2,0,Math.PI*2,"#195089",pointX,pointY-r/2);

     // 绘制两个最小圆

     pie(cxt,r/4,0,Math.PI*2,"#FF072A",pointX,pointY-r/2);

     pie(cxt,r/4,0,Math.PI*2,"#195089",pointX,pointY+r/2);

     cxt.closePath();

     // 恢复状态

     cxt.restore();

 }

 function initTaiji()

 {

     redrawTaiji();

     setInterval(redrawTaiji,500);

 }

 initTaiji();

效果:http://jsfiddle.net/Web_Code/88c9d2g2/embedded/result/

原文首发：http://www.ido321.com/1308.html

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