根据URL下载图片，无需浏览器打开

/**
 * @description 下载图片
 * @author cq
 * @Date 2020-04-15 17:29:22
 * @LastEditTime 2020-04-20 14:01:39
 * @LastEditors cq
 */
const downloadIamge = (imgsrc, name) => {//下载图片地址和图片名
  const image = new Image();
  // 解决跨域 Canvas 污染问题
  image.setAttribute("crossOrigin", "anonymous");
  image.onload = function () {
    const canvas = document.createElement("canvas");
    canvas.width = image.width;
    canvas.height = image.height;
    const context = canvas.getContext("2d");
    context.drawImage(image, 0, 0, image.width, image.height);
    const url = canvas.toDataURL("image/png"); //得到图片的base64编码数据
    const a = document.createElement("a"); // 生成一个a元素
    const event = new MouseEvent("click"); // 创建一个单击事件
    a.download = name || "photo"; // 设置图片名称
    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 + "?" + new Date().getTime();
}

export default downloadIamge