Google and Samsung co-developed the new Watch Face Format (WFF) for Wear OS 4. This new format is easier to maintain and is more power-efficient, leading to longer battery life. Google is urging (via 9o5Google) third-party Wear OS watch face developers to use the new format instead of relying on the older method of creating watch faces.
As more third-party watch faces switch to the new format, they will become more efficient.
Wear OS watch faces made using Watch Face Format are more power-efficient
The Watch Face Format introduced with Wear OS 4 is declarative XML, meaning it doesn't have logic and executable code. Wear OS takes care of all the processing, and developers can focus on creating beautiful-looking and interesting watch faces rather than spending their time on code optimizations and power consumption improvements. Google says the new Watch Face Format requires less maintenance and fewer updates. The company is pushing for simpler watch faces that consume less space and less power.
Moreover, Google has informed developers that compatibility with upcoming watch face complications (with future Wear OS versions) will require them to use the new format. So, newer versions of Wear OS won't display complications in watch faces created using older methods like Jetpack Watch Face Library or Wearable Support Library.
Watch faces created using WFF can also be rendered using the co-processor rather than the main processor on a smartwatch. It means less power is used to display those watch faces than those created using Jetpack Watch Face libraries. Developers say that the WFF doesn't support more advanced features, but it is only a year old at this point, and it is possible that Google will add more capabilities to it in the future.
