标签：div function 宽高 cti get context tco border view
canvas：IE9及以上版本，主流浏览器都支持。
注意：当需要设定canvas的高度时不要写在css中，canvas默认是300x150，在css中设置宽高相当于等比放大或者缩小了，canvas中的内容也会等比放大或者缩小。
<!DOCTYPE html>
<html lang="">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<title></title>
<style>
#canvas {
display: block;
margin: 0 auto;
border: 1px solid #000;
}
</style>
</head>
<body>
<canvas id="canvas" width="600" height="600"></canvas>
<script>
var canvas = document.getElementById(‘canvas‘);
var context = canvas.getContext(‘2d‘);
canvas.onmousedown = function(ev) {
var ev = ev || window.event;
context.moveTo(ev.clientX - canvas.offsetLeft, ev.clientY - canvas.offsetTop);
document.onmousemove = function(ev) {
var ev = ev || window.event;
context.strokeStyle = ‘yellow‘
context.lineTo(ev.clientX - canvas.offsetLeft, ev.clientY - canvas.offsetTop);
context.stroke();
}
document.onmouseup = function() {
document.onmousemove = null;
document.onmousedown = null;
}
}
</script>
</body>
</html>
标签：div function 宽高 cti get context tco border view
原文地址：http://www.cnblogs.com/okaychen/p/6833332.html
