还是前端图片的老话题，花了半天时间，东拼西凑，凑出个demo，优点在于代码少，核心代码就6行，目前刚做了旋转，缩放，裁剪，滤镜要js做，网络上也有现成的代码，
但是想做到自定义的滤镜咋办呢？这还要从底层了解滤镜的实现才行~实际上，我们无论用C++，还是java实现了滤镜，都能移植到js端，原理是相通的。
总之，再次强调，原理很重要，掌握了原理，你就可以任性了。
可以放到http://runjs.cn/里做验证，好棒的在线工具~
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>js+css3</title>
</head>
<style type="text/css">
.clipzone
{
position:relative;
400px;
height:400px;
overflow:hidden;
}
.clipped
{
position:absolute;
}
</style>
<body>
<input type="button" value="rotate" onclick="rotate(20);"/>
<input type="button" value="scale" onclick="scale(1.5);"/>
<input type="button" value="clip" onclick="clip();"/>
<input type="button" value="support_canvas_test" onclick="support_canvas_test();"/>
<div class="clipzone" id="testdiv">
<img class="clipped" id="image1" src="http://www.artup.com/img/icon35.png" width="282" height="220" >
</div>
<script type="text/javascript">
var totalrotate = 0;
var totalscale = 0;
function rotate(sum){
totalrotate = totalrotate + sum;
var obj=document.getElementById("image1");
obj.style.webkitTransform="rotate("+totalrotate+"deg)";
}
function scale(sum){
totalscale = totalscale + sum;
var obj=document.getElementById("image1");
obj.style.webkitTransform="scale("+totalscale+")";
}
function clip(){
var obj=document.getElementById("image1");
obj.style.clip = "rect(20px, auto, auto, 10px)";
}
function support_canvas_test(){
var elem = document.createElement('canvas');
var context = elem.getContext('2d');
alert(typeof context.fillText === 'function'?"support":"not support");
}
var support_css3 = (function() {
var div = document.createElement('div'),
vendors = 'ms o moz webkit'.split(' '),
len = vendors.length;
return function(prop) {
if ( prop in div.style ) return true;
len = vendors.length;
while(len--) {
if ( vendors[len] + prop in div.style ) {
return true;
}
}
return false;
};
})();
</script>
</body>
</html>
