A program that evaluates the memory footprint of the assets in a Watch Face Format (WFF) package.

Watch faces running on Wear OS should be memory efficient so as to ensure the best experience for the user. To this end, the Memory Footprint Evaluator checks how much memory a given watch face package might use. These checks are also conducted by Google Play in reviewing submissions to the Play store.

The memory footprint of a drawable asset is defined as 4 times the number of pixels in the image times the number of frames in the asset (for GIF, WEBP). We typically need 4 bytes to represent a single pixel in memory (one for each of the RGBA channels).

The memory footprint of a watch face is the sum of the memory footprints of all images that are active at any point on a watch face. Some images are mutually exclusive, for example some are rendered only when a specific UserStyleSetting is set or the watch face is in Active or Ambient mode. This is just an estimate, or an upper limit for the memory footprint because some images are conditionally rendered based on expressions. For now, we only take into account user settings and variants.

./gradlew :memory-footprint:jar
java -jar ./memory-footprint/build/libs/memory-footprint.jar --help

No guarantee is made that the following exactly corresponds to the settings used in Google Play reviews, but these represent reasonable settings for evaluation:

java -jar ./memory-footprint.jar --watch-face MyWatchFace.apk \
  --schema-version 2 \
  --ambient-limit-mb 10 \
  --active-limit-mb 100 \
  --apply-v1-offload-limitations \
  --estimate-optimization