小提琴1（使用html2canvas）：http://liveweave.com/HM9hSY
小提琴2（使用html2canvas而不是Codemirror）：http://liveweave.com/rS8yxI
小提琴3（html2canvas与Codemirror一起使用）：http://liveweave.com/TF3Ono
小提琴4（html2canvas使用Codemirror）：http://liveweave.com/hqPoQg
今天我想尝试将iframe导出为图片。我对此做了一些研究，并遇到了一个名为html2canvas的插件，它可以将html保存为图像。 （可以查看文档here）。
Capture HTML Canvas as gif/jpg/png/pdf?
Using HTML5/Canvas/JavaScript to take in-browser screenshots
first fiddle只是一个实验，所以将html保存为图像。 （这个小提琴不使用Codemirror）
second fiddle保存图片但不抓取从源提供的iframe预览。 （这个小提琴不使用Codemirror）
third fiddle无法保存图片。 （这个小提琴不使用Codemirror）
我的问题在于2nd和3rd小提琴，其中[html2canvas] [17]无法保存iframe的预览。
昨天和今天，我一直在玩这个，但我还没有成功。
今天我决定尝试使用Codemirror的代码编辑器来渲染我想要的东西。
基本上我会拍摄身体的截图并将图像嵌入其中。
（这是Fiddle 4我指的是。）
然后我使用window.open在新窗口中打开图像，之后我将代码编辑器重置回原来的位置。
是否可以将iframe的预览/来源保存为图片？我做错了什么来达到这个效果？
$(document).ready(function() {
$("#saveimg").click(function() {
html2canvas($("#preview"), {
onrendered: function(canvas) {
var myImage = canvas.toDataURL("image/png");
$("#imgprev").html("<img src='"+ myImage +"' />");
}
});
});
});<script src="https://raw.github.com/niklasvh/html2canvas/gh-pages/build/html2canvas.js"></script>
<script type="text/javascript" src="http://code.jquery.com/jquery-latest.min.js"></script>
<link type='text/css' rel='stylesheet' href='http://necolas.github.io/normalize.css/3.0.1/normalize.css' />
<div align="center">
<p>
<button id="saveimg">
Save as Image
</button>
</p>
</div>
<iframe id="preview" src="http://duckduckgo.com/"></iframe>
<div id="imgprev"></div>
<canvas id="mycanvas"></canvas>
答案 0 :(得分：1)
我怀疑你遇到了跨域限制。如果您能够在iframe中打开http://mybank.com并获取结果页面的屏幕截图，则可能泄露仅供用户使用的私人信息（将使用其会话）。因此，浏览器不允许你这样做。
答案 1 :(得分：0)
小提琴：http://liveweave.com/LHfsld
小提琴：http://jsbin.com/xutivucanaye/1/edit
这不是最好的解决方案，而且有点奇怪，但我得到了它的工作。好吧。
它不适用于嵌入式图片，iFrame，并且从不拥有完整的CSS支持（您可以从html2canvas's FAQ了解原因）
这是我的整个代码段：
<!DOCTYPE html>
<html>
<head>
<title>Snap a Picture of Preview</title>
<meta charset='utf-8'>
<meta name='viewport' content='initial-scale=1.0'>
<meta http-equiv='X-UA-Compatible' content='IE=9' />
<link type='text/css' rel='stylesheet' href='http://necolas.github.io/normalize.css/3.0.1/normalize.css'/>
<script type='text/javascript' src='http://code.jquery.com/jquery-latest.min.js'></script>
<script src='https://raw.github.com/niklasvh/html2canvas/gh-pages/build/html2canvas.js'></script>
<script src='http://codemirror.net/lib/codemirror.js'></script>
<script src='http://codemirror.net/mode/xml/xml.js'></script>
<script src='http://codemirror.net/mode/javascript/javascript.js'></script>
<script src='http://codemirror.net/mode/css/css.js'></script>
<script src='http://codemirror.net/mode/htmlmixed/htmlmixed.js'></script>
<link rel='stylesheet' href='http://codemirror.net/lib/codemirror.css'>
<link rel='stylesheet' href='http://codemirror.net/doc/docs.css'>
<script src='http://codemirror.net/mode/htmlmixed/htmlmixed.js'></script>
<script src='http://codemirror.net/addon/edit/closetag.js'></script>
<script src='http://codemirror.net/addon/edit/matchbrackets.js'></script>
<script src='http://codemirror.net/addon/selection/active-line.js'></script>
<style type='text/css'>
.CodeMirror {
float: left;
width: 50%;
border: 1px solid black;
}
iframe {
width: 49%;
float: left;
height: 300px;
border: 1px solid black;
border-left: 0;
}
#beforeiframesnap {
position: absolute;
top: -500000px;
left: -500000px;
width: 0;
height: 0;
opacity: 0;
overflow: hidden;
}
</style>
</head>
<body>
<div align='center'>
<button class='snapFrame'>Snap</button>
</div>
<textarea id='code' name='code'><!DOCTYPE html>
<html>
<head>
<meta charset=utf-8>
<title>HTML5 canvas demo</title>
<style>p {font-family: monospace;}</style>
</head>
<body>
<p>Canvas pane goes here:</p>
<canvas id=pane width=300 height=200></canvas>
<script>
var canvas = document.getElementById('pane');
var context = canvas.getContext('2d');
context.fillStyle = 'rgb(250,0,0)';
context.fillRect(10, 10, 55, 50);
context.fillStyle = 'rgba(0, 0, 250, 0.5)';
context.fillRect(30, 30, 55, 50);
</script>
</body>
</html></textarea>
<textarea id='beforeiframesnap'></textarea>
<iframe id='preview'></iframe>
<div id='imgprev'></div>
<script type='text/javascript'>
$('#beforeiframesnap').val("");
// Append JS library to HTML <head>
function appendJSLib(txt) {
var textArea = editor.getValue();
var searchText = textArea.search('<head>');
if(searchText>0) {
txt = '<head>'+'\n'+txt;
var updatedTextArea = textArea.replace('<head>',txt);
editor.setValue(updatedTextArea);
}
else {
reset();
alert('WARNING! The <head> tag seems to be missing in your HTML. Although your code may still work, we highly recommened that you have a valid HTML syntax. Please refer to the new document of correct formatted');
txt = txt+textArea;
htmlEditor.setLine(0, txt);
return false;
}
}
// Append script to HTML <body>
function appendScript(txt) {
var textArea = editor.getValue();
var searchText = textArea.search('<body>');
if(searchText>0) {
txt = '<body>'+'\n'+txt;
var updatedTextArea = textArea.replace('<body>',txt);
editor.setValue(updatedTextArea);
}
else {
reset();
alert('WARNING! The <body> tag seems to be missing in your HTML. Although your code may still work, we highly recommened that you have a valid HTML syntax. Please refer to the new document of correct formatted');
txt = txt+textArea;
htmlEditor.setLine(0, txt);
return false;
}
}
$('.snapFrame').on('click', function() {
$('#beforeiframesnap').val("").val(editor.getValue());
txt = '<'+'script type=\'text/javascript\' src=\'http://code.jquery.com/jquery-latest.min.js\'>'+'</'+'script'+'>';
appendJSLib(txt);
txt = '<'+'script type=\'text/javascript\' src=\'https://raw.github.com/niklasvh/html2canvas/gh-pages/build/html2canvas.js\'>'+'</'+'script'+'>';
appendJSLib(txt);
txt = '<'+'script type=\'text/javascript\'>\n$(document).ready(function() {\n html2canvas($(\'body\'), {\n onrendered: function(canvas) {\n var myImage = canvas.toDataURL(\'image/png\');\n $(\'body\').html(\'<img src=\'+ myImage +\' />\'); window.open(\'javascript:document.write("<img src=\'+ myImage +\' />")\', \'Opened Page\', \'width=660, height=440\');\n }\n });\n});\n</'+'script'+'>';
appendScript(txt);
setTimeout(function() {
editor.setValue($('#beforeiframesnap').val());
}, 1200);
});
var delay;
// Initialize CodeMirror editor
var editor = CodeMirror.fromTextArea(document.getElementById('code'), {
mode: 'text/html',
tabMode: 'indent',
styleActiveLine: true,
lineNumbers: true,
lineWrapping: true,
autoCloseTags: true
});
// Live preview
editor.on('change', function() {
clearTimeout(delay);
delay = setTimeout(updatePreview, 300);
});
function updatePreview() {
var previewFrame = document.getElementById('preview');
var preview = previewFrame.contentDocument || previewFrame.contentWindow.document;
preview.open();
preview.write(editor.getValue());
preview.close();
}
setTimeout(updatePreview, 300);
</script>
</body>
</html>