Path: utzoo!censor!geac!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!apple.com!rmh From: rmh@apple.com (Rick Holzgrafe) Newsgroups: comp.sys.mac.programmer Subject: Re: Advice on icon animation wanted Message-ID: <11592@goofy.Apple.COM> Date: 19 Dec 90 22:05:58 GMT Sender: usenet@Apple.COM Organization: Apple Computer, Inc. Lines: 39 References:<1116@babcock.cerc.wvu.wvnet.edu> <1990Dec18.205338.6800@svc.portal.com> In article <1990Dec18.205338.6800@svc.portal.com> daven@svc.portal.com writes: > Using a VBL task would probably produce the smoothest animation. However, > there is an issue here I've always wondered about. With the non-color > Mac's the VBL task was tied to the vertical blanking of the B&W monitor. > With the color Mac's there is no gaurantee that this is so. I believe the > Apple 13" color monitor refreshes it's screen at a faster rate than the 60Hz > rate of the VBL task queue. So, could animation by means of a VBL task could > cause some flicker on a color monitor? If you use the "standard" VBL queue, yes - on modular Macs, it's no longer tied to any monitor's vertical blanking. (Which means it's misnamed, but that's a quibble. :-) However, there is a way. The Vertical Retrace Manager has been extended to support more than the standard queue; there's now one for every slot in a modular Mac. Two of the new calls are SlotVInstall, which installs a task on the VBL queue for a given slot, and SlotVRemove, which removes the task. These calls are documented in IM V-567. "So how do I find out what slot the monitor is in?" Here I gotta go out on a limb - I haven't tried this stuff, I've just pawed through Inside Mac Vol. V. If I understand what I've read correctly, you use the routines in Chapter 5 "Graphics Devices" to learn about each of the display devices that are available. The GDevice record for each will give you the refnum of the driver for the monitor. Now go to Chapter 23 "The Device Manager" and use the refnum to get the AuxDCE record for the driver; this will give you the slot number. Hope this helps (and I hope it's correct...) ========================================================================== Rick Holzgrafe | {sun,voder,nsc,mtxinu,dual}!apple!rmh Software Engineer | AppleLink HOLZGRAFE1 rmh@apple.com Apple Computer, Inc. | "All opinions expressed are mine, and do 20525 Mariani Ave. MS: 3-PK | not necessarily represent those of my Cupertino, CA 95014 | employer, Apple Computer Inc."