This is the README file for a modified version
of Brian Glaeske's Aquarium BackSpace module.  The file GrayAquarium.tar.Z
contains both source and a m68k/i386 binary for the module.

As the name indicates, GrayAquarium is primarily designed for grayscale next
machines. The fish in this distribution are in grayscale, and the drawing 
methods use a buffered background.  For a 24 bit color system, buffering eats 
up 3 meg of memory, while for my 2 bit nextstation it is only 250K.  (The 
original Aquarium BackSpace module does not use a buffered background.) 

BackSpace.app is a screensaver/background program written by Samuel G. 
Streeper of NeXT Computer Inc., and provided (for free!) as an example
on the developer versions of nextstep 3.0, 3.1, and 3.2.

Improvements:  

1.  Arbitrary background water color.  Since a non-black background color
is not a particularly good screen saver, I suggest that you use this feature
in conjunction with the BackSpaceDuo hack of BackSpace that was posted on
the cs.orst.edu and ftp.informatik.uni-muenchen.de next archives a little
while back.  With BackSpaceDuo, you can use GrayAquarium as a background
and some other more appropriate BackSpace module as the true screen saver.  

2.  A simplified fish drawing routine eliminates strange looking fish when
the fish overlap.  This is where a buffered background is used. 

3.  Flipped Images are stored after the first flip.  Your computer will not jerk to a stop every time a fish gets to a border and has to flip.

4.  Lots of control over number, type, and speed of fish.  El-cheapo 
postscript special effects too!

Major Known Bugs:
 
1.  On my grayscale nextstation, I can see the boxes that the fish are drawn
in if I don't choose a `primary' (white, lightgray, darkgray, black)
background color.  I imagine that color machines will have a similar
problem.

2.  If you change the background color while the background is running, 
the background and the background in the boxes drawn around the fish 
don't initially match.  You have to kill the background and start it up again.

3.  Because I am using a buffered background, this module is a 
memory hog on color machines, as discussed above.

4.  This code will only compile on 3.x machines.  Please excuse me.

Installation:

Using Terminal.app (or even better, Stuart.app), uncompress (or gunzip)
and then tar -xvf the file Aquaruim.tar.Z(gz). Change directory (cd) into
the GrayAquaruim directory.  Type `make install'.  AquaruimView.BackModule will
be created in your Library/BackSpaceViews directory.    

As a courtesy to those of you who have jumped on to the next bandwagon 
recently and have opted not to pay for the NeXT application kit, a copy of 
AquaruimView.BackModule is included with this distribution.  I compiled it with 
the -arch m68k -arch i386 flags, so it should (crossing my fingers here) work 
for both above named architectures. 


Wishing the NeXT community a happy and fulfilling new year,

Paul Griffin   (pgriffin@phys.ufl.edu)
Physics Department
University of Florida
Gainesville, FL 32611

1/5/94

Fixed a couple of initialization bugs that showed up when I tried to use color
fish.

1/9/94