Canvas 绘制旋转太极图
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>01太极</title>
<style type="text/css">
#mal {
display: block;
margin: 80px auto 0;
border: 1px solid gold;
}
</style>
</head>
<body>
<canvas id="mal" width="600" height="600"></canvas>
</body>
<script type="text/javascript">
var canvas = document.getElementById("mal");
var context = canvas.getContext('2d');
var q = 0;
var pointX =0;
var pointY =0;
setInterval(function () {
canvas.width = 600;
canvas.height = 600;
context.translate(300,300);
q += Math.PI/180;
context.rotate(q);
context.beginPath();
context.arc(0, 0, 150, Math.PI * 0.5, Math.PI * 1.5, true);
context.closePath();
context.fillStyle = 'black'
context.fill();
context.beginPath();
context.arc(0, 0, 150, Math.PI * 0.5, Math.PI * 1.5, false);
context.closePath();
context.fillStyle = 'red'
context.fill();
context.beginPath();
context.arc(0, -75, 75, 0, Math.PI * 2, false);
context.closePath();
context.fillStyle = 'black'
context.fill();
context.beginPath();
context.arc(0, 75, 75, 0, Math.PI * 2, true);
context.closePath();
context.fillStyle = 'red'
context.fill();
context.beginPath();
context.arc(0, -75, 35, 0, Math.PI * 2, true);
context.closePath();
context.fillStyle = 'red'
context.fill();
context.beginPath();
context.arc(0, 75, 35, 0, Math.PI * 2, false);
context.closePath();
context.fillStyle = 'black'
context.fill();
}, 1);
</script>
</html>