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1989-08-28
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ShamView Version 2.0!
Revised August 20, 1989
Introducing Sliced Ham, a new Amiga video mode that brings all 4096
colors to your standard Amiga (without the nasty fringing you see in
normal HAM mode).
Sliced Ham works by changing the palette on each video line. A special
algorithm optimizes the palette.
This version will support non-320x200x256 GIF pictures. It's been
successfully tested with MAC II, EGA, and SuperVGA pictures.
Rhett has added a smoothing algorithm that makes even pics reduced from
640x480x256 look good. As an added bonus, reducing them to 320x200 fixes
the aspect ration problem (Mac II pics look slightly stretched and lose the
bottom 80 pixels when viewed with HAMGIF).
If you already have SHAMview 1.11, just download SUPERCON2.0 and you'll be
updated.
_______________________
Sliced Ham Version 1.1
Copyright 1989 Rhett Anderson
All Rights Reserved
Revised July 23, 1989
Hello Fellow Amiga Enthusiasts.
You have stumbled upon what I believe are the highest-quality images
that you can achieve with a standard Amiga. Trust me--you will be
stunned.
Bug fixes in version 1.1:
* Supercon now saves in IFF format.
* ShamView now loads IFF format.
* Supercon is more forgiving if you tell it something that it doesn't
want to hear. Notably, you can now just type its name for info
(instead of a guru), and it's no longer likely to make bogus files
when you type in the wrong filename. It's still somewhat flakey if
you don't have as much RAM as it wants.
* Supercon can accept up to four filenames. If you supply more than
one, the program will put each picture into a corner of the screen.
* ShamView is also more forgiving about filenames.
Introduction
Welcome to Sliced Ham. Over the last year I've been thinking about
writing a 24-bit paint program for the Amiga. Sliced Ham is a
byproduct of that product.
In effect, Sliced Ham gives you HAM images that lack the fringes so
commonly found in that mode. It works by changing the palette on each
and every scan line. 15 colors are changed each line during the
horizontal retrace period. It just so happens that there is precisely
enough time for these changes. Just as well, because you wouldn't want
the background color to change on each line (although I suppose you
could cover up the mess with sprites--I'll have to think about it).
This package provides you with a way of looking at those great
256-color 320 by 200 VGA GIF files. Soon I'll have conversion units to
let you view 24 bit Digi-View, Framegrabber, and other files in
(virtually) all their glory. I'd appreciate any information about file
formats, including Mac II pictures.
The programs are slow (at least until you've made it to the final
converted Sliced Ham pictures). They are currently written in M2Sprint
(not slouch speed-wise), but since they're so computation intensive,
I'm converting them to ML. So far the best I've been able to do is 14
seconds for an optimized 24-bit to Sliced Ham conversion. Many kinks
remain, however.
To use the program, type shamview filename, where filename is the
already-converted image.
To convert a GIF image, type giftotmp giffile, then supercon tmpfile.
Example:
giftotmp fish.gif fish.gif.tmp
supercon fish.gif.tmp
shamview fish.gif.tmp.sham
You'll probably want to rename the final file to fish.sham, to indicate that it is a Sliced Ham picture.
Advantages of Sliced Ham
Sliced Ham is easy to display. Game programmers can easily throw up a
Sliced HAM screen with only a couple dozen extra lines of source code.
Sliced Ham eats up virtually no extra processor time.
Sliced Ham looks good because it removes the 15 most offensive HAM
smears on each scanline.
A Commercial
If you like my program, please drop me a line at COMPUTE!'s Amiga
Resource. If you feel really generous, subscribe to my magazine. We
have 7 serious Amiga programmers at COMPUTE!. I don't believe you'll
find that any of our competitors can say the same thing.
Pay special attention to the December issue of the magazine for
several Sliced Ham programs, including a new converter, displayer,
overlay program, image processor, and more.
These programs are not in the public domain. Please distribute them
freely on bulletin boards an electronic services, but do not place
them on public domain or shareware disk collections. (Go ahead and
spread the programs to your friends, just make sure no money changes
hands.) I must make this rule because my job depends on sales of our
disk products. It doesn't make sense for me to undercut myself.
The version of Sliced Ham I am distributing uses a raw format for
storage of the files. I will soon be registering a format (SHAM) with
CATS. I'll post more information about it soon. I hold no claim to the
technique or file format.
If you're impressed by these pictures, just think--these are 256 color
images. You will be startled by the 4096-color ones captured by
digitizers and scanners.
Technical Note: An IFF Sliced Ham picture file looks just like any
other ILBM file. However, Sliced Ham pictures have an extra chunk
(called SHAM) consisting of a version word (currently 0), then 200
different palettes of 16 colors. Each color takes up a word and is in
the form 0rgb.
Rhett Anderson
Associate Editor
COMPUTE!'s Amiga Resource
324 W. Wendover Ave.
Greensboro, NC 27408
I ask for no money, but please send some to the author of giftotmp.
P.S. Thanks to PLinkers Harv Laser and Kermit // Capt*Video for their
suggestions and bug reports, and to fellow Amiga programmers at C!AR
(Denny Atkin, Troy Tucker, Tim Midkiff, Randy Thompson, Dale McBane,
Jim Fuchs) for their encouragement, and to my fellow ASDF members,
including John Toebes, Wes Howe, and Doug Walker, for listening to my
Sliced Ham discussion at the 1th Annual Guru Meditation. And finally,
thanks to John, Paul, George, and Ringo, who sang to me while I
worked.
P.S.S. Sorry for any bugs, but I program pretty fast and carelessly
(this project had taken just a few days) since I have so many things
going on; COMPUTE!'s Amiga Resource, the Mapping The Amiga book Randy
and I are writing, developing for the Amiga, developing for the Atari
Hand-Held game machine, being married, having a nearly-normal social
life, etc. Enough already! Have fun with SHAM. And thanks to Denny for
being my interface with the world of online computing.