(PECL gmagick >= Unknown)
Gmagick::haspreviousimage — Checks if the object has a previous image
Returns true if the object has more images when traversing the list in the reverse direction.
此函數沒(méi)有參數。
Returns true if the object has more images when traversing the list in the reverse direction, returns false if there are none.
錯誤時(shí)拋出 GmagickException。