Path2D 构造函数

实现

factory Path2D([path_OR_text]) {
  if (path_OR_text == null) {
    return Path2D._create_1();
  }
  if ((path_OR_text is Path2D)) {
    return Path2D._create_2(path_OR_text);
  }
  if ((path_OR_text is String)) {
    return Path2D._create_3(path_OR_text);
  }
  throw new ArgumentError("Incorrect number or type of arguments");
}