public static int pixelValue(int frameNumber, int x, int y) {
    return ((frameNumber & 0xff) << 16) | ((x & 0xff) << 8) | ((y & 0xff));
  }
Implementation of {@link AnimatedDrawableBackend} for unit tests.
animated-base/src/test/java/com/facebook/imagepipeline/animated/testing/TestAnimatedDrawableBackend.java