保存下载图片图片

downloadIamge: function(imgsrc, name) {
    let image = new Image();
     image.setAttribute("crossOrigin", "anonymous");
     image.onload = function() {
       let canvas = document.createElement("canvas");
       canvas.width = image.width;
       canvas.height = image.height;
       let context = canvas.getContext("2d");
       context.drawImage(image, 0, 0, image.width, image.height);
       let url = canvas.toDataURL("image/png"); //得到图片的base64编码数据
       let a = document.createElement("a"); // 生成一个a元素
       let event = new MouseEvent("click"); // 创建一个单击事件
       a.download = name || "海报"; // 设置图片名称没有设置则为默认
       a.href = url; // 将生成的URL设置为a.href属性
       a.dispatchEvent(event); // 触发a的单击事件
     };
     image.src = imgsrc;
   },
   saveImg: function() {
     let img=this.Img
     this.downloadIamge(img, '二维码');
   },