@Override
  public String toString() {
    return "SwirlFilterTransformation(radius=" + radius + ",angle=" + angle + ",center="
      + center.toString() + ")";
  }
@param radius from 0.0 to 1.0, default 0.5
@param angle  minimum 0.0, default 1.0
@param center default (0.5, 0.5)
transformations/src/main/java/jp/wasabeef/glide/transformations/gpu/SwirlFilterTransformation.java