Index of /atarilibrary/atari_cd04/VIEWCONV/G_I_F/MONO

      Name                    Last modified       Size  Description


[DIR] Parent Directory        11-May-2007 20:58      -  
[   ] MGIF.MAN                02-Mar-1992 12:05    10k  
[TXT] MGIF.TTP                03-Jun-1991 17:07    48k  
[TXT] TODO                    03-Jun-1991 17:30     1k  
[IMG] VOGEL.GIF               05-May-1992 12:30    29k  


mgif 3.2
--------

This is a new version of a GIF viewer for mono STs. The major change
(version 1.1 or 1.2 was the last I posted) is to add "flicker" mode
display to simulate grayscale and to add lots more image processing
functions. However, a few things were removed and need to be added
(like image rotation). This only works on monochrome and is hardwired
to 640x400 tubes! It is also coded to use about 1.4 MB of memory,
so it will handle up to 640x625 images. It also means that the
binary won't run on a 1 MB system. It also uses line A (at least
I did not use any undocumented stuff :-).

Here are the major changes:

	- mgif is now more or less interactive only. It does not make
	  sense to work batch with flicker mode. Most of the command
	  line switches are gone.

	- There is now no file output (yet). I hope to develop some
	  sort of file format for flicker palettes. Don't hold your
	  breath, though...

	- Image processing functions include histogram equalization,
	  contrast stretching, inversion, blurring, brightening, median
	  filtering, thresholding, log scaling, resizing (only powers
	  of 2: 2x, .5x, ...), convolutions, etc.

	- GIF decoding is now a single entry point so source could be
	  used for other applications. Flicker code is as well. Just
	  pass it a pointer to the grayscale image along with its size.

This is a GIF viewer for mono STs. It uses Floyd-Steinberg dithering to
represent color images on bi-level devices as well as the so-called
"flicker palette". I was graciously presented with a copy of some routines
to do the flicker stuff from Klaus Pedersen (micro@imada.dk) and I adapted
it for use with mgif. He used a combination of F-S and rapid (Vsync) screen
switches, resulting in suprisingly good grayscale image quality on a
monochrome monitor.

There are 2 posts: binary and source.

It handles reasonable image sizes, but clips to max of 640x400. Reasonable
here means PC-ish (VGA, etc) images, not 1280x1024 images which need a
heck of alot of memory and/or different coding methods (i.e. GIF direct to
screen. It should handle up to 8-bit images (which is max GIF format, I
believe). I have limited the size of the internal arrays to hold the raw
GIF image and the decoded image. It could fit on an empty 1 MB system (if
recompiled) and will handle images up to 400,000 pixels, plus or minus.
The included binary will need 1.4 MB of memory. To get it to fit on a
1 MB system, change the CodedGIF[] array dimensions to about 150,000 and
the Raster[] and TransRaster[] array dimensions to 310,000. It should then
be able to handle most images 640x480 or smaller in 1 MB. I have not tried
this (since I have a mega 4) so you may need to play around. Look at the
mgif.h file for the defines.

enjoy...

-bill rosenkranz
rosenkra@convex.com


Binary manifest:

Name          Length    Stowage    SF   Size now  Date       Time    CRC
============  ========  ========  ====  ========  =========  ======  ====
MGIF.1           10991  Crunched   56%      4865   3 Jun 91  11:26p  D0BB
MGIF.TTP         49029  Crunched   43%     28085   3 Jun 91  10:07p  9DFA
README            4382  Crunched   38%      2597   3 Jun 91  11:17p  58FD
TODO               621  Crunched   25%       469   3 Jun 91  10:30p  6A01
        ====  ========            ====  ========
Total      4     65023             45%     36016


Source manifest:

Name          Length    Stowage    SF   Size now  Date       Time    CRC
============  ========  ========  ====  ========  =========  ======  ====
FLICKER.C        16996  Crunched   51%      8343   3 Jun 91   6:39a  5D85
MAKEFILE          2012  Crunched   44%      1127   3 Jun 91   6:44p  02F5
MGIF.C           41687  Crunched   53%     19891   3 Jun 91   9:13p  AD3E
MGIF.H            2541  Crunched   46%      1378   3 Jun 91   6:34a  DC44
MGIF.MAN          8534  Crunched   45%      4739   3 Jun 91  11:03p  0093
PROCESS.C        24882  Crunched   58%     10458   3 Jun 91  10:05p  4F3B
READGIF.C        26038  Crunched   55%     11855   3 Jun 91   6:39a  70F4
README            4382  Crunched   41%      2597   3 Jun 91  11:17p  58FD
TODO               621  Crunched   25%       469   3 Jun 91  10:30p  6A01
        ====  ========            ====  ========
Total      9    127693             53%     60857