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From: muswick@vs2.uh.cwru.edu
Newsgroups: comp.sys.dec
Subject: Re: GIGI????
Message-ID: <1991Mar26.160557.1@vs2.uh.cwru.edu>
Date: 26 Mar 91 21:05:57 GMT
References: <5876@tahoe.unr.edu>
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Organization: Image Analysis Center, Univ. Hospitals of Cleveland"
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In article <5876@tahoe.unr.edu>, lsmith@unssun.nevada.edu (The Master) writes:
> 
>  I recently purchased a DEC GIGI and Barco monitor, from what I can
> find out, it has an 8k memory, and will emulate a VT52. Does anybody
> out there in DEC land know anything about GIGIs? What are they, what
> were they used for? 
> 

I used to work with GIGI's alot - in fact I have the programmers ref man set.
I also may have the GIGI libraries on tape somewhere.

Simply a GIGI is very similar to a VT125/VT240 - but the ansi keyboard
sequences are not the full vt100 setup.  Since it has been 6 years since I
worked with one, I don't remember what is missing from the ansi/vt100 which
prevents full vt100 emulation.  I do remember using the ansi mode and vt100 on
the SET TERM in dcl - but having to repaint the screen with EDT alot to see
anything.

I'll check my docs which are home and post the specs, but I recall the GIGI
had 720 (800?) x 480 resolution x 3 (4?) bits of color/grey scale in groups of
8 pixels.  The colors I think were either on or off so there was a total of 8
colors (black, white, red, green, blue, magenta, yellow, and cyan). And I seem
to recall an intensity bit. Which allowed for a total 15 colors (since low
intensity black is still black). Also there was a peculilar memory structure in
that the horizontal pixels were bit mapped per each byte and each byte could
have its own foreground and background color.  I know this sounds confusing, so
I will diagram below:

                              720 pixels --->
aaaaaaaabbbbbbbbccccccccdddddddd ...               480 pixels
eeeeeeeeffffffffgggggggghhhhhhhh ...                   |
iiiiiiiijjjjjjjjkkkkkkkkllllllll ...                   |
.                                                      V
.
.

Now each letter is a pixel, that can be turn off or on.  Each group of 8 pixels
(a's , b's , c's)  and so on have a foreground and background value associated
with them, foreground color displayed when the pixel is on, and background when
off.  In hardware what DEC had was 16 bits for every 8 pixels.

Bit number as follows:
 0  1  2  3  4  5  6  7    8      9   10     11    12    13    14     15
p1 p2 p3 p4 p5 p6 p7 p8 fred fgreen fblue fintens bred bgreen bblue bintens 

I used to display images using a dithering and a combiantation 4 bits at a
time.

Speed was slow, esp. limited by a rs232 line.

All programs written for the GIGI would work on a VT125 or VT240.  Infact
usually with better quality since the vt240 did not have the 8 bit grouping.

The barco's on the other hand were usefull as 2nd monitors for our rgb image
processing systems.

Good luck
Gary Muswick
Supv, Image Analysis Center
University Hospitals of Cleveland
muswick@vs2.uh.cwru.edu