请教一个问题，如何在图片上写数字，使用arkts？

async function drawTextToImage(img: image.PixelMap, text: string): Promise<PixelMap> {
  const imageInfo = await  img.getImageInfo()
  const width = imageInfo.size.width
  const height = imageInfo.size.height
  const offC2d = new OffscreenCanvasRenderingContext2D(width, height, {
    antialias: true
  })
  // 配置 OffscreenCanvasRenderingContext2D
  offC2d.font = 'normal bolder 60px sans-serif'
  offC2d.fillStyle = 'rgb(255,0,0)'
  offC2d.textAlign = 'center'
  offC2d.textBaseline = 'middle'
  // 绘制图像
  offC2d.drawImage(img, 0, 0, width, height, 0, 0, width, height)
  // 绘制文字
  offC2d.fillText(text, width / 2, height / 2)
  return offC2d.getPixelMap(0, 0, width, height)
}