Watch Face Format (WFF) is an XML-based format for defining the appearance and behavior of watch faces for Wear OS.

This repository contains materials for helping developers work with the Watch Face Format to build both watch faces and watch face design tools.

The XSD specification provides you with the specification needed in order to build validation into your watch face creation tools and processes.

There are different versions of the specification: The latest is version 2 which builds and expands on version 1. Different versions have different Wear OS version support. To understand the differences in capabilities and compatibility please see this guide.

The XSD validator is a tool that allows you to check whether specific watch face XML file represent valid WFF or not, including providing error information to assist in debugging the watch face.

When used on Wear OS devices, watch faces built with WFF must pass a memory-use validation test to ensure that they run efficiently. For more guidance on this subject, see the guidelines on developer.android.com.

The Memory footprint evaluator allows you to check watch faces ahead of submission to Play or to incorporate memory usage checking into your tools and processes.

The Watch Face Format optimizer is a tool which can be incorporated into your work flow to reduce the memory usage of your watch face at runtime, by optimizing aspects of your WFF XML and your resources.

For WFF samples, please see the Wear OS Samples repository on GitHub.

This codebase is automatically formatted using spotless To reformat, from the project root directory, run ./gradlew spotlessApply.

Watch Face Format is distributed under the Apache 2.0 license, see the LICENSE file.