@Override
  public Path getPath() {
    if (isPathValid) {
      return path;
    }

    path.reset();

    if (hidden) {
      isPathValid = true;
      return path;
    }

    PointF size = sizeAnimation.getValue();
    float halfWidth = size.x / 2f;
    float halfHeight = size.y / 2f;
    float radius = cornerRadiusAnimation == null ?
        0f : ((FloatKeyframeAnimation) cornerRadiusAnimation).getFloatValue();
    if (radius == 0f && this.roundedCornersAnimation != null) {
      radius = Math.min(roundedCornersAnimation.getValue(), Math.min(halfWidth, halfHeight));
    }
    float maxRadius = Math.min(halfWidth, halfHeight);
    if (radius > maxRadius) {
      radius = maxRadius;
    }

    // Draw the rectangle top right to bottom left.
    PointF position = positionAnimation.getValue();

    path.moveTo(position.x + halfWidth, position.y - halfHeight + radius);

    path.lineTo(position.x + halfWidth, position.y + halfHeight - radius);

    if (radius > 0) {
      rect.set(position.x + halfWidth - 2 * radius,
          position.y + halfHeight - 2 * radius,
          position.x + halfWidth,
          position.y + halfHeight);
      path.arcTo(rect, 0, 90, false);
    }

    path.lineTo(position.x - halfWidth + radius, position.y + halfHeight);

    if (radius > 0) {
      rect.set(position.x - halfWidth,
          position.y + halfHeight - 2 * radius,
          position.x - halfWidth + 2 * radius,
          position.y + halfHeight);
      path.arcTo(rect, 90, 90, false);
    }

    path.lineTo(position.x - halfWidth, position.y - halfHeight + radius);

    if (radius > 0) {
      rect.set(position.x - halfWidth,
          position.y - halfHeight,
          position.x - halfWidth + 2 * radius,
          position.y - halfHeight + 2 * radius);
      path.arcTo(rect, 180, 90, false);
    }

    path.lineTo(position.x + halfWidth - radius, position.y - halfHeight);

    if (radius > 0) {
      rect.set(position.x + halfWidth - 2 * radius,
          position.y - halfHeight,
          position.x + halfWidth,
          position.y - halfHeight + 2 * radius);
      path.arcTo(rect, 270, 90, false);
    }
    path.close();

    trimPaths.apply(path);

    isPathValid = true;
    return path;
  }
This corner radius is from a layer item. The first one is from the roundedness on this specific rect.
lottie/src/main/java/com/airbnb/lottie/animation/content/RectangleContent.java