HarmonyOS 如何根据base64获取图片的尺寸

参考：

let base64Helper = new util.Base64Helper();
let buffer: ArrayBuffer = base64Helper .decodeSync(this.imageBase64, util.Type.MIME).buffer as ArrayBuffer;
let imageSource = image.createImageSource(buffer);
let opts: image.DecodingOptions = { editable: true };
this.pixelMap = await imageSource.createPixelMap(opts);
this.pixelMap.getImageInfo().then((imageInfo : image.ImageInfo) => {
  if (imageInfo == undefined) {
    console.error(`Failed to obtain the image pixel map information.`);
  }
  let wit = imageInfo.size.width;
  let hig = imageInfo.size.height;
  console.log(`Succeeded in obtaining the image pixel map information., ${JSON.stringify(wit)}, ${JSON.stringify(hig)}`);
})