Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!wuarchive!udel!haven.umd.edu!ni.umd.edu!ni.umd.edu!zben From: zben@ni.umd.edu (Ben Cranston) Newsgroups: comp.sys.mac.programmer Subject: Re: what I want to see in future Apple computers Summary: Gamma table animation Message-ID: <1991Jun20.172609.9795@ni.umd.edu> Date: 20 Jun 91 17:26:09 GMT References: <31504@hydra.gatech.EDU> <1991Jun18.135838.3444@potomac.ads.com> Sender: usenet@ni.umd.edu (USENET News System) Organization: University of Maryland at College Park Lines: 27 Nntp-Posting-Host: ni.umd.edu In article evensen@husc9.harvard.edu (Erik Evensen) writes: > Well, I hate to be a stick in the mud but to set the record straight, > it is my understanding, after reading the Palette Manager section of > Inside Mac VI that direct devices (i.e., those whiz-bang 24 bit > colorcards) do not have CLUT's either. To quote: "Color table > animation doesn't work on a direct device -- it has no color table." > (p. 20-11) Now maybe there's a trick to getting a direct device to > act like one which has a CLUT but I haven't seen anything about it; > correct me if I'm wrong. OK! :-) I understand all mainline Apple video cards have a Gamma correction table, and that it is at least theoretically possible to do color table animation of sorts by modifying this table on the fly. I've never done so and hope to never *have* to do so. BTW "Gamma" refers to the non-linear relationship between electron beam current and perceived light intensity. A "Gamma table" is a lookup table that (somehow) provides a compensation function. Supposedly you want a linear Gamma function if you're taking a picture of the screen, because film's response is linear with number of incident photons, but for viewing you want a different function. Try pushing the "options" button in the Monitors control panel and see what kind of gamma choices your particular monitor supports.