Hi all: I am undertaking an program which processes big xpm file. It have basic function such as zoomin, zoomout and so on. In my program, I want this operations can response user's button events as quickly as posible. I use GIMP to open this big xpm file and try this operations on, It works very well. So I am very eager to know the technic details which GIMP take to realize this functions. Can you give me some advice? thanks! shigang shigang@xxxxxxxxxxxxxx