private void invalidate() {
    isPathValid = false;
    lottieDrawable.invalidateSelf();
  }
This was empirically derived by creating polystars, converting them to
curves, and calculating a scale factor.
It works best for polygons and stars with 3 points and needs more
work otherwise.
lottie/src/main/java/com/airbnb/lottie/animation/content/PolystarContent.java