Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!mailrus!husc6!m2c!wpi!dseah From: dseah@wpi.wpi.edu (David I Seah) Newsgroups: comp.sys.apple Subject: Re: What to do with the GS Message-ID: <8405@wpi.wpi.edu> Date: 16 Feb 90 17:30:53 GMT References: <900214.16355107.044715@UWEC.CP6> <1990Feb15.152154.22827@ncsuvx.ncsu.edu> <12154@smoke.BRL.MIL> Reply-To: dseah@wpi.wpi.edu (David I Seah) Organization: Worcester Polytechnic Institute, Worcester ,MA Lines: 99 In article <12154@smoke.BRL.MIL> gwyn@brl.arpa (Doug Gwyn) writes: >In article <1990Feb15.152154.22827@ncsuvx.ncsu.edu> rnf@shumv1.ncsu.edu (Rick Fincher) writes: >>Adding greater vertical resolution would require a more expensive monitor >>unless you do it in interlace mode with all of the problems that involves. > >There are no real problems with interlacing! Your home TV set proves it. >The regular Apple Color monitor sold for use with the IIGS has sufficient >phosphor density and beam focus already to support interlacing (I can >clearly see the dark gaps between the scan lines on mine, and they're >almost as wide as the scan line). I don't know if the Apple Color monitor >happens to be able to handle the particular sync that interlacing requires. You can sometimes see the effects that interlacing has on computer graphics by tuning into your local cable company channel guide. If the screen layouts are poorly designed, you can see the interlace flicker on horizontal lines. The standard way to get around this is to make sure your horizontal lines are at least two or three scanlines high, but then you've just killed your gain in vertical resolution. If the field rate was bumped up to 50Hz or more, the interlace jitter effects would go away, but with that much bandwidth you might as well go with a noninterlaced display scheme. Another way you can reduce the effects of interlaced video is by designing your graphics with low contrast in mind. Sticking a bright red pixel on top of a bright blue pixel would jitter like crazy. A dark pixel over a light pixel would have the same effect. If you drew something with a spread or "wash" of soft blues, your jitter would be less apparent. That's why broadcast TV looks OK...the millions of colors blend together. I wonder if the 12 bit color resolution of the GS could prevent really effective use of this technique. One could find out, I imagine, by stomping over to the nearest Amigoid and demanding to see their absolutely greatest 4096 color HAM mode picture and see how much it jitters. As for sync, I'm guessing that the current monitor could handle it. If you've ever dropped the monitor into 50Hz vertical sync and watched the scanlines go looney-tunes, perhaps you'd guess the same thing. Interlaced video requires only a small change in the video timing. >>Adding more colors would be compatible with existing equipment and improve >>things a lot. Some of the 320 by 200 pictures on the gs are pretty impressive >>in 16 colors. 640 by 200 in 256 colors would be very impressive, work on >>existing low cost monitors, etc. > >I agree that more colors is important; however, apparent visual resolution >is not much improved by increasing the color resolution; better spatial >resolution is also required. 640x400 is roughly what a good NTSC TV set >provides, and while not terrific at least it is about what the public is >accustomed to seeing on CRT devices. If an interlaced video mode is allowed, I'd like to see it with 256 color capability for the reasons discussed above. While Apple's working on that, I'd like to see them expand the color resolution to 8 bits per R,G,B component. We don't have to have 24 bit color DISPLAY capability, but the color registers should be 24 bit RGB internally for future expandability. Currently, we have 4 bits for each Red, Green and Blue stored in two bytes. These could be treated as the most significant nibbles, while taking another byte and the extra 4 bits could provide the least significant nibbles. I can just see programmers complaining 10 years from now, "Why didn't those jackasses in engineering put ALL THE #*@&#^$ BLUE COMPONENT BITS IN ONE BYTE???", to which we'd lamely reply, "well, it maintained compatibility with the old modes" :-) [cost of monitor debate deleted] >>More pixels is better for detailed work like CAD large text displays etc. > >Even modest text displays need better vertical resolution! 10-point >Shaston on the IIGS is much harder to read than people should reasonably >be expected to deal with, even on a fairly low-end machine. Yeah! The vertical resolution on our text display is really crummy compared to that of even the cheapest IBM clone. I wonder if the current monitor can be pushed to 350 lines of vertical resolution with a corresponding redefinition of the character set...that would be nice. >>One thing I've seen on the Mac is that lots of pixels make the text smaller >>on a given size monitor. Either that or more detailed fonts of the same >>screen size can be used. I've seen Mac users with their noses pressed up >>against 19 inch monitors because the characters were so small they were hard >>to read. The characters were well formed because of the resolution but they >>were real small, hence dificult to work with. > >I think Mac displays tend to have "squarer" pixels, at least the B&W models. >That gives a crisper impression even though the resolution may really be >the same. Interlacing on a monitor like the Apple Color monitor would help >approach the same effect. The pixels are gloriously square for both color and black and white Macs. They also had 512x342 or some bizarre number like that on the old 9 inch black and white tube...much crisper-looking because of the pixel density on such a small screen. I believe that reading text on a 640x400 interlaced screen would give a person tremendous eyestrain. Try using the Amiga's "Intuition" desktop-like environment set to 640x400 interlaced res... the fonts are crisp and well defined - and jump up and down like a cat on a barbecue. -- Dave Seah | O M N I D Y N E S Y S T E M S - M | Internet: dseah@wpi.wpi.edu | User Friendly Killing Machines | America Online: AFC DaveS