html5 图片旋转
找了很久，终于找到图片旋转的方法了，现在向大家分享一下！
<!DOCTYPE HTML>
<html>
<head>
<title>test rotate</title>
<script type="text/javascript">
function startup() {
var canvas = document.getElementById('canvas');
var ctx = canvas.getContext('2d');
var img = new Image();
img.src = 'Penguins.jpg';
img.onload = function() {
ctx.translate(img.width / 2, img.height / 2);
ctx.rotate(30 * Math.PI / 180);
ctx.drawImage(img, 0, 0, 164, 164);
}
}
</script>
</head>
<body onload='startup();'>
<div id="pw_body" style="100%;height:100%">
<canvas id="canvas" style="position: absolute; left: 300px; top: 300px;" width="800" height="600"></canvas>
</div>
</body>
</html>
效果图：
