双恒 借助toDataURL实现将HTML5 Canvas的内容保存为图片
将HTML5 Canvas的内容保存为图片主要思想是借助Canvas自己的API - toDataURL()来实现，具体实现如下，感兴趣的朋友可以参考下哈，希望对你有所帮助
主要思想是借助Canvas自己的API - toDataURL()来实现，整个实现
HTML + JavaScript的代码很简单。
<html>
<meta http-equiv=X-UA-Compatible content=chrome=1>
<head>
<script>
window.onload = function() {
draw();
var saveButton = document.getElementById(saveImageBtn);
bindButtonEvent(saveButton, click, saveImageInfo);
var dlButton = document.getElementById(downloadImageBtn);
bindButtonEvent(dlButton, click, saveAsLocalImage);
};
function draw(){
var canvas = document.getElementById(thecanvas);
var ctx = canvas.getContext(2d);
ctx.fillStyle = rgba(125, 46, 138, 0.5);
ctx.fillRect(25,25,100,100);
ctx.fillStyle = rgba( 0, 146, 38, 0.5);
ctx.fillRect(58, 74, 125, 100);
ctx.fillStyle = rgba( 0, 0, 0, 1); // black color
ctx.fillText(Gloomyfish - Demo, 50, 50);
}
function bindButtonEvent(element, type, handler)
{
if(element.addEventListener) {
element.addEventListener(type, handler, false);
} else {
element.attachEvent('on'+type, handler);
}
}
function saveImageInfo ()
{
var mycanvas = document.getElementById(thecanvas);
var image = mycanvas.toDataURL(image/png);
var w=window.open('about:blank','image from canvas');
w.document.write(<img src='+image+' alt='from canvas'/>);
}
function saveAsLocalImage () {
var myCanvas = document.getElementById(thecanvas);
// here is the most important part because if you dont replace you will get a DOM 18 exception.
// var image = myCanvas.toDataURL(image/png).replace(image/png, image/octet-stream;Content-Disposition: attachment;filename=foobar.png);
var image = myCanvas.toDataURL(image/png).replace(image/png, image/octet-stream);
window.location.href=image; // it will save locally
}
</script>
</head>
<body bgcolor=#E6E6FA>
<p>
<canvas width=200 height=200 id=thecanvas></canvas>
<button id=saveImageBtn>Save Image</button>
<button id=downloadImageBtn>Download Image</button>
</p>
</body>
</html>运行效果如下：
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