关于javascript:html2canvas截图另存图片模糊问题解决办法

在应用html2canvas.js发现一个问题，当你截图区域有背景图片的状况下：

html2canvas对如下写法清晰

<img src="" alt="" width="100%" height="100%">

html2canvas对如下写法含糊

<div class="bgImg">...</div> bgImg{   width          : 200px;   height         : 200px;   background     : url('../img/bgImg.jpg');   background-size: 100% 100%;}

至于为什么会这样，我也不晓得。版本为html2canvas 1.0.0-rc.5

附上另存为事件代码。

html2canvas(document.querySelector("#yourId"), { dpi: 96 }).then(canvas => {    var imgDataUrl = canvas.toDataURL("image/jpeg");    downLoadFile("某某文件", imgDataUrl);})function downLoadFile(fileName, canvasImg) {   var a = document.createElement('a')   a.href = canvasImg;   a.download = fileName   let event = document.createEvent("MouseEvents")   event.initMouseEvent("click", true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null)    a.dispatchEvent(event)}