@Nullable
  @RestrictTo(RestrictTo.Scope.LIBRARY)
  public Typeface getTypeface(Font font) {
    Map<String, Typeface> fontMap = this.fontMap;
    if (fontMap != null) {
      String key = font.getFamily();
      if (fontMap.containsKey(key)) {
        return fontMap.get(key);
      }
      key = font.getName();
      if (fontMap.containsKey(key)) {
        return fontMap.get(key);
      }
      key = font.getFamily() + "-" + font.getStyle();
      if (fontMap.containsKey(key)) {
        return fontMap.get(key);
      }
    }

    FontAssetManager assetManager = getFontAssetManager();
    if (assetManager != null) {
      return assetManager.getTypeface(font);
    }
    return null;
  }
Returns the {@link LottieImageAsset} that will be rendered for the given id in the Lottie animation file.
The id is the asset reference id stored in the "id" property of each object in the "assets" array.
<p>
The returned bitmap could be from:
* Embedded in the animation file as a base64 string.
* In the same directory as the animation file.
* In the same zip file as the animation file.
* Returned from an {@link ImageAssetDelegate}.
or null if the image doesn't exist from any of those places.
lottie/src/main/java/com/airbnb/lottie/LottieDrawable.java