@Override
  public AnimatedDrawableBackend forNewBounds(@Nullable Rect bounds) {
    Rect boundsToUse = getBoundsToUse(mAnimatedImage, bounds);
    if (boundsToUse.equals(mRenderedBounds)) {
      // Actual bounds aren't changed.
      return this;
    }
    return new AnimatedDrawableBackendImpl(
        mAnimatedDrawableUtil, mAnimatedImageResult, bounds, mDownscaleFrameToDrawableDimensions);
  }
An {@link AnimatedDrawableBackend} that renders {@link AnimatedImage}.
animated-base/src/main/java/com/facebook/imagepipeline/animated/impl/AnimatedDrawableBackendImpl.java