Performance is an important consideration when creating for the watch. Use the following tips to optimize your watch face.
Display and color tips
- Create a watch face as dark as possible. This can vary depending on the design of your watch face, but the darker the watch face, the less power it consumes. This applies to both always-on (ambient) and normal mode. For more information, see Color and brightness of a watch face.
- Minimize the frequency of screen updates. Components that require frequent screen updates require more rendering, which takes more power.
- Keep in mind that objects that are not displayed by style selection or conditionals do not affect performance because they are not rendered. Objects that are not displayed because of tag expressions are partially rendered.
- Do not use extensive masking as this requires a large amount of computation.
- Optimize the number of components displayed. If multiple components form a single object, merge it beforehand and import it. For more information, see Combine bitmap assets.
- Do not include unnecessary components, especially if they are not shown on the watch face.
- Group components with the same purpose. For example, if you want to attach a shadow image to an hour hand, you can group the hour hand image and the shadow image and rotate the group together.
- Use as few complications as possible. When complications receive data, the system is kept busy updating what is displayed on the watch face.
- Do not use unnecessarily high-resolution images.
- Use as small a bitmap as possible.
If only a part of a large bitmap is displayed on the screen, crop it as much as possible. For more information, see Reduce the size of your bitmap assets.
Animations also tax performance. Use the WebP format rather than GIF format. This maintains the same quality but reduces the APK file size. Encode your animation file to the size of the screen, with as low a frame rate as possible. Any frame rate higher than 15 frames per second drains battery life. For more information, see Best practices for animations.