Path: utzoo!attcan!uunet!cs.utexas.edu!sun-barr!ames!pasteur!ucbvax!agate!ronzoni!lippin From: lippin@ronzoni.berkeley.edu (The Apathist) Newsgroups: comp.sys.mac.programmer Subject: Re: Help: Using CopyBits for Update Message-ID: <24376@agate.BERKELEY.EDU> Date: 12 May 89 19:50:34 GMT References: <1617@neoucom.UUCP> <7254@hoptoad.uucp> Sender: usenet@agate.BERKELEY.EDU Reply-To: lippin@math.berkeley.edu Organization: Authorized Service, Incorporated Lines: 23 Recently tim@hoptoad.UUCP (Tim Maroney) wrote: >Maybe I'm being dense, but what is the advantage to keeping an >offscreen bitmap in a terminal emulator and using it for updates? >Individual updates will go faster. However, you will spend more time >overall in QuickDraw, because what would ordinarily be a one-step >process has a new step added. It's a matter of trading time (and memory) now for time later. Since the amount of time spent in CopyBits is generally small, this is often a good trade, particularly if the drawing is complex. But, in a terminal program, the time to draw is also small, so I imagine there would be little advantage. A further advantage of CopyBits is that it avoids the flicker of doing erase and redraw on the screen. But for text, this is more simply avoided by using srcCopy mode. --Tom Lippincott lippin@math.berkeley.edu "Ask a fish head anything you want to -- It won't answer you; they can't talk."