ZGIFDatatype 39.7 - minor update to release 39.5
	September '93

	Another FAST Utility Written by Michael Zucchi

This is a replacement for any of the other gif datatypes available.  What
makes it considerably better than any of the others?  Speed.  On an
A1200 it will load GIF's using multiview approximately the same speed as
loading IFF ILBM pictures.  And a lot faster if loading from floppy disks.

In addition, asynchronous file reading routines have been incorporated
into the code which allow it to load pictures virtually independent
of I/O speed.  For example a 680x480x256 gif picture will load off of
floppy disk within a few seconds of one loading off of a hard drive.
(this is in an Amiga 1200, with no fastmem)

It requires a 68020 or greater CPU, and of course Release 3.0 or greater
of the system software.

Main features:

    o	SPEED.  Try it, after using this you wont want to be without it!
    o	Supports most gifs (only some esoteric, and mostly unused features
    	of the GIF8?a standard have been ignored)
    o	Uses async file reading for greater performance - on an A1200 will
	load a picture the same speed off of floppy as off of hard drive!
    o	100% Assembly language, very optimised.
    o	Custom chunky to planar conversion, that is reasonably fast (a version
    	using WritePixelLine8() runs about 50% the speed of this version)
    o	Its FREE! (this is of course the best bit)


Main limitations: (hey, its not _perfect_ after all)

    o	OM_WRITE BOOPSI method not yet implemented.  Expect this in a future
    	release.
    o	Only decodes pictures with a global colour table.  Most gif loaders
    	do the same, and most writers write them.
    o	Ignores any local colour tables (but still decodes picture).  Could
    	lead to a bad palette.

Distribution:

This program is FreeWare, _please_ give it to your friends, your enemies
ANYONE who could possibly use it or otherwise spread it around.  Datatypes
are a really excellent addition to the OS but there aren't yet enough
quality datatypes out there.
The original achive in which this text file is placed may be included in
any other release of non-commercial software, so long it remains
intact.  If anyone wants to put it on a commercial release, just contact me.

Installation:

    Copy the gif.datatype file into your sys:classes/datatypes/ drawer
    Copy the Datatypes/GIF file (and its icon) into DEVS:Datatypes/

Reboot your machine or use AddDataTypes to enable it.

Nice isn't it? :)



The Author:

I'm a poor :( student currently doing 3rd year Computer Systems Engineering
at The University of South Australia, at the Levels campus
(read: swamp/shithole/isolated dump :).

I can be reached via email at:

  9107047w@lux.levels.unisa.edu.au

or Aussie Post via:  ('home' address)

  Michael Zucchi
  PO box 824
  Waikerie SA 5330	<- SA = South Australia

or if ya live in Adelaide, ring Freds BBS and give us a bell.

I'd like to hear about any major/minor bugs.  I'd like to see lots of $$
too :)


Thanks and the rest:

Thanks to the guys who supplied me with those odd (and i mean _odd_ :)
gif's to test some of the weirder stuff.  And the other guys who suggested
i do it.  And to all those guys who mailed me with bugs.  Hopefully the
screenmode selection is a bit better now fellas?

Thanks also to the C= software eng's for making such a _cool_ OS.


Sick and tired of all those crappy, huge and slow compilers out there?
 --> AmigaE2.5 will be here soon! <--

Look out for ZGif 1.0 - also comming soon to an Amiga near you!
(quickfeaturelistincludes:ofastestgifloaderavailableforamigaoveryfastiffilbm
loaderofastiffilbmsaveroretinagraphicsboardsupportoaslfilerequesteroaslscree
nmoderequesteroworkbenchstartupokeyboardcontrolowb2.0or3.0oandmuchmuchmore!)

       ///
      ///   Michael Zucchi
  \\\///    9107047w@lux.levels.unisa.edu.au
   \\\/     Computer Systems Engineer (in the making)


Note:
     "The Graphics Interchange Format(c) is the Copyright property of
      CompuServe Incorporated. GIF(sm) is a Service Mark property of
      CompuServe Incorporated."

 History

 39.0	Initial version
 39.1	Now does any depth gif, not only 4 or 8, used to ignore.
 39.2	Now supprts interlaced gifs, used to ignore.
 39.3	Added better viewmode selection via BestModeIDA(), uses
 	the 'workbench' monitor (if possible).
 39.4	Fixed a tiny bug in extension block skipping code.
 39.5	Monitor selection was up shit creek.  Now it should work a lot
 	better, and select a decent monitor (i only had Euro72 active,
 	so it seemed to be ok before).  No longer tries to clone the
 	workbench monitor.
 39.6	Was passing incorrect dimensions to the datatype object via the
 	DTA_NominalHoriz/Vert tags.  Caused multiview to open a strange
 	sized window if run on workbench.
 39.7	Changed GetBestMode() code - again.  Now it asks for a mode with
 	roughly square pixels (actually 130:100 seems to be best aspect???).
 	Appears to work better anyway.