将HTML5 Canvas的内容保存为图片借助toDataURL实现_HTML5教程-查字典教程网
将HTML5 Canvas的内容保存为图片借助toDataURL实现
将HTML5 Canvas的内容保存为图片借助toDataURL实现
发布时间:2017-01-07 来源:查字典编辑
摘要: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。window.on...

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">

<div>

<canvas width=200 height=200 id="thecanvas"></canvas>

<button id="saveImageBtn">Save Image</button>

<button id="downloadImageBtn">Download Image</button>

</div>

</body>

</html>

运行效果如下:

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