HarmonyOS 鸿蒙Next 通过Canvas画布toDataURL()生成的图片 如何保存到本地？

export async function save(canvasContext: CanvasRenderingContext2D) {  
  // Get PixelMap  
  const pixelMap = canvasContext.getPixelMap(0, 0, canvasContext.width, canvasContext.height)  
  // Packing image.  
  const imagePackerApi = image.createImagePacker();  
  const packOptions: image.PackingOption = {    
    format: 'image/jpeg',    
    quality: 100  
  }  
  const imageData = await imagePackerApi.packing(pixelMap, packOptions);  
  console.info(`imageData's length is ${imageData.byteLength}`)  
  // Get album's path.  
  const context = getContext(this);  
  const media = mediaLibrary.getMediaLibrary(context);  
  const publicPath = await media.getPublicDirectory(mediaLibrary.DirectoryType.DIR_IMAGE);  
  const currentTime = new Date().getTime();  
  // Create image asset.  
  const imageAssetInfo = await media.createAsset(    
    mediaLibrary.MediaType.IMAGE,    
    `image_${currentTime}.jpg`,    
    publicPath  
  );  
  const imageFd = await imageAssetInfo.open('rw');  
  await fs.write(imageFd, imageData);  
  // Image resource release.  
  await imageAssetInfo.close(imageFd);  
  imagePackerApi.release();  
  await media.release();
}