Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!usc!apple!dlyons From: dlyons@Apple.COM (David A. Lyons) Newsgroups: comp.sys.apple2 Subject: Re: windows, modems and /bin/share... Message-ID: <53107@apple.Apple.COM> Date: 20 May 91 07:48:46 GMT References: <9105151708.AA15055@apple.com> <3588@kluge.fiu.edu> Organization: Apple Computer Inc., Cupertino, CA Lines: 27 In article <3588@kluge.fiu.edu> acmfiu@serss0.fiu.edu (ACMFIU) writes: >[...] >quickdraw does draw faster to off-screen grafports because it doesn't have >to do the 2/4-bit conversion when drawing stuff on-screen (did i get this >right dave?). As Jim Murphy pointed out, pixel maps are still 2 or 4 bits deep whether they're on the screen or not. As Jawaid pointed out, storing to screen memory happens at 1 MHz, whereas offscreen memory is usually full processor speed. And finally, as I'm pointing out right now, QuickDraw *does* special-case the *screen* for some operations (a few more on ROM 3 than on ROM 1). Offscreen grafports are very useful when your images take much longer to generate than to copy onto the screen. You don't want to regenerate a fractal, for example, every time somebody moves a window so that more of it is visible. If your drawing is straightforward, there's no advantage to using an offscreen grafport. -- David A. Lyons, Apple Computer, Inc. | DAL Systems Apple II System Software Engineer | P.O. Box 875 America Online: Dave Lyons | Cupertino, CA 95015-0875 GEnie:DAVE.LYONS CompuServe:72177,3233 Internet:dlyons@apple.com My opinions are my own, not Apple's.