KGeomLoop2d.isValid() method

检查该二维环是否有效：是否自相交， 是否封闭，轮廓线是否一个一个首尾向量。 Whether the loop is valid: - no self-intersection, - closed, - connected one by one and tail to head.

Signature:

isValid(): boolean;

Returns:

boolean

返回二维环是否有效。

Return true if the loop2d is valid.