void setDepth(float depth);
This function is EXPERIMENTAL. The behaviour of this function, the name of this function, and anything else documented about this function may change without notice in a future release of PHP. Use this function at your own risk.
swfdisplayitem->setdepth() sets the object's z-order to depth. Depth defaults to the order in which instances are created (by adding a shape/text to a movie)- newer ones are on top of older ones. If two objects are given the same depth, only the later-defined one can be moved.