-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 In article <20040416001641.22218.00000518@mb-m06.aol.com>, Obsbedia2 wrote: >Besides gifs, ][GIF has a converter for RLE files. I tried searching for >.RLE images on Google, as I do for .GIFS, but only gifs and jpgs came up. > >What's an RLE file? I don't think I've ever run across one, but run-length encoding (RLE) is a very simple form of data compression, suitable for images of low complexity. There must've been a standard of some sort at one time that implemented it for swapping images...whether it was cross-platform or specific to the Apple II, I couldn't say. (RLE typically works by writing a code for an input value, followed by a count of consecutive occurrences. Consider this input stream: 00 00 00 00 11 11 22 22 22 33 33 33 33 33 You could encode it this way: 00 04 11 02 22 03 33 05 To decode, you'd read pairs of values and repeat one value the number of times indicated by the other...repeat 00 four times, 11 twice, etc. to recover the original stream: 00 00 00 00 11 11 22 22 22 33 33 33 33 33 For some types of data, you might modify the idea to only do this for certain values (for Hi-Res images, you might only do this for occurrences of 00, 7F, 80, and FF if you have large black areas and white areas in your images).) _/_ / v \ Scott Alfter (remove the obvious to send mail) (IIGS( http://alfter.us/ Top-posting! \_^_/ rm -rf /bin/laden >What's the most annoying thing on Usenet? -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.2.4 (Linux) iD8DBQFAf4FaVgTKos01OwkRAgeiAJ9Ts7PwR1Cpi7CdlUUcARcX7HkMDQCdHOlw P3UPbg9DThpwhb6ujeiKkXw= =qHAS -----END PGP SIGNATURE----- In article <20040416001641.22218.00000518@mb-m06.aol.com>, obsbedia2@aol.com (Obsbedia2) wrote: > Besides gifs, ][GIF has a converter for RLE files. I tried searching for > .RLE > images on Google, as I do for .GIFS, but only gifs and jpgs came up. > > What's an RLE file? > JaY (R)un (L)ength (E)ncoded - A realy crude (but depending on the file, potentially quite effective) compression method that works by taking repeating sequences of bytes, and replacing them with a single instnace of the byte, and a count of how many times it occurred in the input stream, saving Rawlength - 2 (or sometimes 3) bytes per encoded run. Obviously, break-even is at the 2 (or 3) byte mark, with everything after that being true space savings. Line art is a real good candidate for it, since there are typically long runs of the same byte, interspersed with a few bytes of "other stuff", followed by more long runs of identical bytes. I seem to recall that it never really caught on all that well. Whether that was because .gif was already pretty much estalished, or otherwise, I can't remember. I do know I haven't seen one in a LONG time... -- Don Bruder - dakidd@sonic.net - New Email policy in effect as of Feb. 21, 2004. I respond to Email as quick as humanly possible. If you Email me and get no response, see Short form: I'm trashing EVERYTHING that doesn't contain a password in the subject. Jay wrote: >What's an RLE file? It is a Run Length Encoded image file. Usually, RLE is employed on monochrome files, and, instead of encoding the complete bit map for the image, it encodes the lengths of "runs" of 1s and 0s, which is usually saves space for "line art" and text, since the runs tend to be many more bits than the bits required to represent their lengths (the "ceiling" of the log base 2 of the number of bits). -michael Check out amazing quality sound for 8-bit Apples on my Home page: http://members.aol.com/MJMahon/ obsbedia2@aol.com (Obsbedia2) wrote in message news:<20040416001641.22218.00000518@mb-m06.aol.com>... > Besides gifs, ][GIF has a converter for RLE files. I tried searching for .RLE > images on Google, as I do for .GIFS, but only gifs and jpgs came up. > > What's an RLE file? > JaY Others have told you what RLE is. RLE's were popular in the 80's, before GIF came along. They didn't store color information, just picture, so they were used for Monochrome images. I think they got their start on Apple-II's, because I remember seeing source for Apple-II RLE's that got TI users started on writing the decoders. There was even one put inside a terminal program for viewing the graphics on-line. I've got tons of RLE's somewhere, and you could probably find a lot of them on the TI ftp site at ftp.whtech.com, in various disk collections. Ben The technique of rle is used in the PCX bitmapped picture format. PCX was not use on Apple afaik, but popular in the old days on the PC. Easy to generate and still accepted by most graphical packages. I have specs and Turbo Pascal code on my MSX pages. MSX & X10 & 6502 & Philips bouwdozen & te koop: http://www.hansotten.com