Dear Jeremy Here is a bit more wordy explanation about what I am interested in: First of all I am completely oblivious to internal X server code structure so please bare with me. What I am looking at is at xorg- server-1.4.2-apple42/hw/xquartz/xpr/xprFrame.c file where there is a pointer callback structure: static RootlessFrameProcsRec xprRootlessProcs, where there is a xp_copy_bytes function supplied as an accelerated version for blitting stuff. All in all the code in xorg-server-1.4.2-apple42/hw/xquartz is heavily filled with xp_ funcs. So I guess the first question is - what code I should be looking at? Next one is as follows: if not xp* funcs what technology do you use to blit fast to screen? I don't think you're allocating and dropping CImage's or something in that way - it's too slow, thus you're probably using something to do quick drawings and you can somehow get to the 'raw' pixel data for window backing store somehow. Am I right? If yes, how do you do this? The last question was about not XCopyArea for X11 which is O.K. but about an analogue of XCopyArea written for OS X without any X11 support. Suppose I am porting X11 application to pure OS X what can you advise me to use to emulate XCopyArea with source being the window. Here I desperately need your expertise because there does not seem to be a convinient way to do so on OS X (or may be I am mistaken). Last question how do I get very quickly the bitmap bits for the particular window on screen? Getting it using Cocoa is very slow. Using QuickDraw is not an option.. So what to do? Best regards, Platon