Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!samsung!munnari.oz.au!metro!ipso!fawlty!johnmac
From: johnmac@fawlty.towers.oz (John MacLean)
Newsgroups: comp.sys.apple2
Subject: Re: 3200 graphics
Message-ID: <440@fawlty.towers.oz>
Date: 15 Aug 90 06:08:16 GMT
References: <438@fawlty.towers.oz> <1990Aug13.085955.11424@utstat.uucp>
Reply-To: johnmac@fawlty.ips.oz (John MacLean)
Organization: Tower Technology, Lane Cove, NSW, Australia
Lines: 58

>John, you have been talking about these graphics' translators for some time
>now for the GS. Do they exist? That is, where can they be obtained?>

I have finally seen the printed manual for TGE 4.2 from RWP - about time too
- so I assume you can buy it - contact RWP again.
My GIF and 3200 toolsets are now in beta (with most of the rest of the
library disk).
In other words, although TGE 4.2 is here you may be waiting till late in the
year to get the first library disk.
I assure you the library disk will not cost much if I have any say in it.

>>Some scanlines in GIFs will have > 16 colors in them - so you still have
>>to do some palette optimizations to get good results.
>>The quality of this optimization is what makes a good picture.
>>This can take a LONG time [stuff deleted]
>
>How long can it take? Are we talking minutes or hours(days!)?

At present I do things with brute force - I find THE best colors for each
scanline.
This has taken 1.5 hours! (no Transwarp) for a single 200 palette image such
as the one I mentioned.
Optimization to 16 palettes can take up to 5 minutes.
Obviously, the fewer the palettes, and the fewer colors used in each palette,
the easier the optimization becomes.
I have a new (faster) algorithm designed but I have to get my library
disk installer script fixed up first and then my IFF toolset which is
under way, and then my planned PCX (PC Paintbrush toolset), and then ....
The thing is, you get excellent results - and once its done you can
save it off in any format you like.
I know this sort of time is REALLY SILLY, so do not bother telling me.
And yes I write it all in assembler - how do you think I can save a GIF
file in 20 seconds flat.

>While I'm at it how it is possible to have a freehand drawing program
>which will know when you've reached the 16 color limit in a particular
>line?

Keep frequency tables for each scanline and each color.
This does take a LOT of memory.
$2000 bytes per scanline => a lot.

My opinion has always been that you should allow the user to choose any
of the 4096 colors, use a scheme as above, and have huge lookup tables
to translate colors dynamically as their frequency causes them to appear/
disappear from each palette.
I played around with the code a while back and it did not look too bad,
but It could be slow in real use.

>Philip McDunnough

John MacLean.

-- 
This net: johnmac@fawlty.towers.oz.au                   Phone: +61 2 427 2999
That net: uunet!fawlty.towers.oz.au!johnmac             Fax:   +61 2 427 7072
Snail:    Tower Technology, Unit D 31-33 Sirius Rd,     Home:  +61 2 960 1453
          Lane Cove, NSW 2066, Australia.