canvas 2d 接口支持同层渲染且性能更佳,建议切换使用。详见文档:https://developers.weixin.qq.com/miniprogram/dev/component/canvas.html#Canvas-2D-%E7%A4%BA%E4%BE%8B%E4%BB%A3%E7%A0%81也可以参考社区用户的文章https://developers.weixin.qq.com/community/develop/article/doc/000242073903a04e082ab595b52013
https://developers.weixin.qq.com/community/develop/doc/000a2ee7eec880fc693b5741f51800?highLine=fail%2520canvas%2520is%2520empty