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 will consume. This applies to both 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.
- Don't 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 this keeps the system 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 a GIF. This maintains the same quality but reduces the APK size. Encode your animation file to the size of the screen. Encode your animation with as low a frame rate as possible. Any frame rate higher than 15 frames per second drains your battery life. For more information, see Best practices for animations.