/**
 *
 * @param url 图片路径
 * @param ext 图片格式
 * @param callback 结果回调
 * 类型暂定any
 */
export  function getUrlBase64(url: any, ext: any, callback: any) {
    let canvas = document.createElement("canvas") as any;   //创建canvas DOM元素
    const ctx = canvas.getContext("2d") as any;
    const img = new Image;
    img.crossOrigin = 'Anonymous';
    img.src = url;
    img.onload = function () {
        canvas.height = 35; //指定画板的高度,自定义
        canvas.width = 35; //指定画板的宽度，自定义
        ctx.drawImage(img, 0, 0, 35, 35); //参数可自定义
        const dataURL = canvas.toDataURL("image/" + ext);
        callback.call(this, dataURL); //回掉函数获取Base64编码
        canvas = null;
    };
}