canvas篇--初学canvas案例---canvas签名
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效果如下
代码如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style>
*
margin: 0;
padding: 0;
body,
html
width: 100%;
overflow: hidden;
body
background-color: green;
#test
background-color: #fff;
position: absolute;
top: 0px;
left: 0px;
bottom: 0px;
right: 0px;
margin: auto;
</style>
</head>
<body>
<canvas id="test" width="500" height="500">
</canvas>
</body>
<script type="text/javascript">
window.onload = function ()
var canvas = document.getElementById("test");
if (canvas.getContext)
var ctx = test.getContext('2d')
canvas.onmousedown = function (ev)
ev = ev || event;
if (canvas.setCapture)
canvas.setCapture()
ctx.beginPath()
ctx.moveTo(ev.clientX - canvas.offsetLeft, ev.clientY - canvas.offsetTop)
document.onmousemove = function (ev)
ev = ev || event;
ctx.save()
ctx.strokeStyle = "pink"
ctx.lineTo(ev.clientX - canvas.offsetLeft, ev.clientY - canvas.offsetTop);
ctx.stroke();
ctx.restore()
document.onmouseup = function ()
document.onmousemove = document.onmouseup = null;
if (document.releaseCapture)
document.releaseCapture();
return false;
</script>
</html>
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