html2canvas 保存网页截图图片不显示

问题描述

两张图片，一张是用户上传的图片，另一张是模板图，中间是透明的，可以制作相框，并保存。使用html2canvas对两个img标签进行截图。在写demo的时候html2canvas没有报错但是所截的是空白，若换成文字就可以。

原因分析

找了半天才知道，如果截图部分包含图片的话，程序必须放在服务器下面进行，不然的话就是空图片。

It will not work if you run this html file without any web server . If you are playing around on your PC then install XAMPP or any other web server (Easiest option http://www.apachefriends.org/en/xampp.html) and put the image ,JavaScript and HTML code in C:\xampp\htdocs (if C dirive is your installation drive) and run using the server. I have tested it in Chrome and its working.
参考链接：http://stackoverflow.com/questions/14004607/html2canvas-not-working-on-google-chrome

##代码实例

<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<script src="js/jquery.js"></script>
	<script src="js/html2canvas.js"></script>
	<script src="js/canvas2image.js"></script>
</head>
<style type="text/css">
	img{
		width: 500px;
		height: 300px;
		position: fixed;
	}
	#div1{
		height: 500px;
		width: 100%;
	}
	#div2{
		position: fixed;
		bottom: 0;
		background: red;
	}
</style>
<body>
	<div id="div1">
		<img id="img1" src="img/01.jpg">
		<img id="img2" src="img/02.jpg" style="width:300px">
	</div>
	<div id="div2"></div>
</body>
<script type="text/javascript">
	html2canvas($('#div1'), {
	   onrendered: function(canvas) {
	     var oImgPNG = Canvas2Image.saveAsPNG(canvas, true); 
	     $('#div1').hide();
	     $('#div2').html(oImgPNG);
	  },
	  width: 500,
	  height: 500
	});
</script>
</html>