华宇链接html5之Canvas路径绘图、坐标变换应用实例

本文写一个html5的时钟应用程序试手主要设置了坐标变换的平移（translate）和旋转变换（ratate），以及html5 Canvas的路径绘图，beginPath，closePath，rect，arc等多的也不说了，直接上代码有需要的朋友可以参考下

代码如下:

<html>

<head>

</head>

<body>

<canvas id="myCanvas" width="600" height="300">你的浏览器还不支持哦</canvas>

var 华宇登录 c = document.getElementById("myCanvas");

var cxt = c.getContext("2d");

var slen = 60;

var mlen = 50;

var hlen = 40;

cxt.strokeRect(0, 0, c.width, c.height);

cxt.beginPath();

cxt.strokeStyle = "#00f";

cxt.fillStyle = "#00f";

cxt.arc(200, 150, 5, 0, 2 * Math.PI, true);

cxt.fill();

cxt.closePath();

cxt.beginPath();

cxt.strokeStyle = "#00f";

cxt.arc(200, 150, 100, 0, 2 * Math.PI, true);

cxt.stroke();

cxt.closePath();

cxt.beginPath();

cxt.translate(200, 150); //平移原点；

cxt.rotate(-Math.PI / 2);

cxt.save();

for (var i = 0; i < 60; i++) {

if (i % 5 == 0) {

// cxt.fillStyle = "#ff0000";

cxt.fillRect(80, 0, 20, 5);

cxt.fillText("" + (i / 5 == 华宇登录 0 ? 12 : i / 5), 70, 0);

} else {

// cxt.strokeStyle = "#00f";

cxt.fillRect(90, 0, 10, 2);

}

//document.getElementById("div1").innerText += " " + i;

cxt.rotate(Math.PI / 30);

}

cxt.closePath();

var ls = 0, lm = 0, lh = 0;

function Refresh() {

cxt.restore();

cxt.save();

cxt.rotate(ls * Math.PI / 30);

cxt.clearRect(5, -1, slen+1, 2+2);

cxt.restore(); cxt.save();

cxt.rotate(lm * Math.PI / 30);

cxt.clearRect(5, -1, mlen+1, 3+2);

cxt.restore(); cxt.save();

cxt.rotate(lh * Math.PI / 6);

cxt.clearRect(5, -3, hlen+1, 4+2);

var time = new Date();

var s = ls=time.getSeconds();

var m = lm=time.getMinutes();

var h = lh=time.getHours();

cxt.restore();

cxt.save();

cxt.rotate(s * Math.PI 华宇登录 / 30);

cxt.fillRect(5, 0, slen, 2);

cxt.restore(); cxt.save();

cxt.rotate(m * Math.PI / 30);

cxt.fillRect(5, 0, mlen, 3);

cxt.restore(); cxt.save();

cxt.rotate(h * Math.PI / 6);

cxt.fillRect(5, -2, hlen, 4);

}

var MyInterval = setInterval("Refresh();", 1000);

</script>

</body>

</html>