This article is from the newsnet system. It details techniques used in GIF and APAC viewers. Tidied by Dean Garraghty.¢-----------------------------------¢¢Goody! I get to answer another question! Well.... GIF stands for (correct me if I'm not exactly quoting it, guys!) Graphics Interchange Format. I'm not sure how it's formatted, but it IS compressed. There are at least 2 GIF viewers for the 8-bits. I don't think either care if you have 256k or 16k..(well..256 or 32...).¢¢The programs are AT8GIF.COM, which stands for Atari8-bit GIF viewer and APACVIEW.COM (I have APACVW12.COM as well.. my ARC of the original APACVIEW release is really thrashed for some reason...) I'm pretty sure both require a file with RGB data. AT8GIF.COM is good as far as resolution, but that's it. It can go up to hi-res (320x192x2 - 320 pixels/line, 192 lines/screen, 2 colors) if needed (I have a Mac picture somewhere). It's other mode is 160x192x4. The only problem is how it shows the colors. It shows them as red, green, and blue (and black). When mixed, these colors can look good, but most pictures I have SUCK with this viewer. It sets up 2x2 pixels to show the colors. Purple would be red,blue/blue,red .. actually, more like red,blue/black,red or something. I don't really recommend this program, but it's good to have just in case.¢¢The other program, APACView was made after the programmer (forgot his name) read about APAC screens in Antic or Analog magazine. APAC stands for Any Point, Any Color. Since you have the 800xl (well..more like NOT a 400/old 800), you have the GTIA chip (George's Television Interface Adapter?). It's capable of taking 8k of memory and displaying it as 80x192x16. Now, this looks REALLY good. If, say, you have a digitized ComputerEyes picture in 16color mode, you can switch APACview into b/w mode and view it fine. (it has 2 loads.. GIF (*.GIF) and APAC (*.PI9) ). The 3 GTIA modes are: 16 shades of a background color (I made TRUE 256 colors by changing the backgd down the screen 16 times! using a DLI)...9 colors that can be changed... and 16 colors of a certain brightness (except black, black stays darkest.) (Note that ONLY mode 9 - 16shades - can view 16 shades, using POKE or SETCOLOR will only give you 8 shades!)¢¢What APACView does is alternate the modes on the screen (using a DLI, I'll suppose...what else!?). This gives you 256 simulated colors anywhere on the screen by coloring on the color line, and brightening it on the shade line, so if you step back it will look ok. The only problem is because the mode lines are alternated for this program, it gives the GIF file 1/2 as many lines down the screen to use (not too much of a problem because AT8GIF did pretty much the same thing). It ALSO is only in 80 columns, giving you a HORRIBLE resolution of 80x96 vs.160x192, but who cares, because as I said, AT8GIF works about the same as far as ridding you of resolution!¢¢What >I<'d like to see is a really fast page flipper to double the vertical resolution. There would be a full screen of color, and a full screen of shades, then flip between them and simultaneously change between the two modes (color & bw). I've tried.. 'course that was with BASIC, (turboBASIC, mind you, but still)... Maybe when I get Action!??? ¢¢Also, a neat thing to do is double the horizontal res. by, again, having 2 screens (doing both uses 4 screens..32k, it would JUST fit on a 48k machine with a reasonably small dos, say MyDOS or AtariDOS must continue later!!!¢¢Bill Kendrick.¢¢
