html2canvas截取页面

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 常用的插件就是html2canvas。插件的使用本身很简单，这里说的是如何将其生成的canvas保存为图片。

1、引入  

import html2canvas from 'html2canvas'

 <div >
    <el-button type="info" size="mini" @click="tohomedetail" class="back">返回</el-button>
    <el-button type="info" size="mini" @click="savecanvas" class="back">保存地图</el-button>
    <div id="allmap" style="height:800px" class="canvas" ref="canvas"></div>	
</div>
<div id="canvasContainer" style="display:none"></div>

let oCard = document.querySelector("#bsCard");//要转换成canvas的元素
let oContainer = document.querySelector("#canvasContainer");//装canvas的容器

html2canvas(oCard).then(function(canvas) {
	oContainer.appendChild(canvas);
	//延迟执行确保万无一失，玄学
	setTimeout(() => {
		var type = 'png';
		var oCanvas = oContainer.getElementsByTagName("canvas")[0];
		var imgData = oCanvas.toDataURL(type);//canvas转换为图片
		// 加工image data，替换mime type，方便以后唤起浏览器下载
		imgData = imgData.replace(_fixType(type), 'image/octet-stream');	
		fileDownload(imgData);
	}, 0)
});

function _fixType(type) {
	type = type.toLowerCase().replace(/jpg/i, 'jpeg');
	let r = type.match(/png|jpeg|bmp|gif/)[0];
	return 'image/' + r;
};

//唤起浏览器下载
function fileDownload(downloadUrl){
	let aLink = document.createElement('a');
	aLink.style.display = 'none';
	aLink.href = downloadUrl;
	aLink.download = "下载文件名xxx.png";
	// 触发点击-然后移除
	document.body.appendChild(aLink);
	aLink.click();
	document.body.removeChild(aLink);
}

外部图片或链接会无法截取