Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!swrinde!elroy.jpl.nasa.gov!jato!hanauma.jpl.nasa.gov!hyc From: hyc@hanauma.jpl.nasa.gov (Howard Chu) Newsgroups: comp.sys.atari.st Subject: Re: Graphics on the STE - v. generally speaking... Message-ID: <1991Apr3.004047.511@jato.jpl.nasa.gov> Date: 3 Apr 91 00:40:47 GMT References: <1245@exua.exeter.ac.uk> Sender: news@jato.jpl.nasa.gov Organization: SAR Systems Development and Processing, JPL Lines: 56 Nntp-Posting-Host: hanauma.jpl.nasa.gov In article <1245@exua.exeter.ac.uk> SAMcinty@exua.exeter.ac.uk (Scott McIntyre) writes: > I've posted a few bits and pieces lately about the graphics capabilities >of the ST series, but I don't seem to have learned much, so, here are >all my questions....if you can help me, I would greatly appreciate it... > > Is the usual method of de-giffing a colour (heck, even mono) picture >onto an ST merely the clumping of black and white dots, at a horrendous >resolution? I know that a lot of effort went into writing these programmes There is no usual method, GIF is not an ST standard picture format. It is a (*gag*) PC oriented format designed by the Software Geniuses at Compu$erve. (double-*gag*...) >2) Does the STE have gray scales, you know, proper shades of gray, not >just the nearness of black and white pixels? How can I use these scales? >When I look in magazines I see some AMAZING pictures on SM124s that are >gray, but look as sharp as a photograph! They ought to! 600 x 400 should >yield fantastic quality...so, where is it? "Gray-scales" on the STe typically refers to using a color monitor on the STe and just filling the palette (16 entries) with gray. On the STe since there are 4 bits per color (R,G,B) and "gray" is just equal values of each color, you can get 16 distinct intensities of gray *on a color monitor* and only in low-rez. In medium rez you can only get 4 levels. There's nothing special going on here, you're just using your color system with a pretty unimaginative selection of colors. >3) Is there any source ftpable that has a collection, or even just >a few, of these images? What might they be called? What kind of suffixes >will they have? GR8? GR9? Try .SPC, .SPU, or .SPS for Spectrum 512 pictures. Spectrum 512 only uses low-rez as well. >4) Is it possible to get Gif images to look remotely nice on a STE? Well, it's fairly simple to display a full 256-color GIF image, if that's what you mean. I have code doing this in my port of Fractint 12. Using frame-swapping to (almost) double the number of bits per pixel just about squares the number of colors to choose from, and also squares the number of colors displayable at once. (Fractint lets you use 16 colors in med-rez and 256 in low-rez.) This is pretty reasonable, given that regular VGA rez only allows 16 colors onscreen in 640x480 mode. I wonder why other folks haven't tried these tricks with their GIF decoders. I am taking the GIF decoding routine from Fractint and using it with my frame-swapping code, and getting pretty tolerable results. For you with your monochrome system, well... Frame-swapping can work there too, but I'm not sure how many colors you can reasonably expect to get. I just received some code from someone else that is supposed to render 256 grayscales on a monochrome monitor, I haven't gotten to try it yet. (Looking thru, it seems to really only give 4 or 16, but that's still better than black&white, eh?) -- -- Howard Chu @ Jet Propulsion Laboratory, Pasadena, CA Disclaimer: How would I know, I just got here!