Antv G6 downloadFullImage 导出图片清晰度不够

downloadFullImage 导出图片清晰度不够

     /**
     * 图片下载
     * @param text 图片名称
     */
    download(text) {
      window.oldRatio = window.devicePixelRatio
      window.devicePixelRatio = 2
      this.graph.downloadFullImage(text, 'image/png', {
        backgroundColor: '#fff',
        padding: [30, 15, 15, 15]
      })
      setTimeout(() => {
        window.devicePixelRatio = window.oldRatio
      }, 100)
    }