WhichLayer

Which Layer is this point in?

Starting at the topmost layer check to see if this point (x,y) occurs in this layer. If it does return the pointer to this layer. Return NULL if there is no layer at this point.

li

pointer to LayerInfo structure

x

see next

y

coordinate in the BitMap

layer

pointer to the topmost layer that this point is in NULL if this point is not in a layer

You should at least lock the Layer_Info of the layer or the result is unpredictable as the layer arrangement may change while this function is running.

<graphics/layers.h>