Vine was written by Dan Heller in Dec 1985 while at SRI International.
The Port to X windows done on Friday March 9, 1990 by Dan Heller.
This readme has been modified to provide for the latest additions.
This program draws vines all over your computer. If you're running X,
it writes to the root window. If you're running on a sun workstation,
and *not* using X (e.g. compiled with -lpixrect) it writes directly to
the frame buffer.
"vines" are long stems with leaves on them.
If you don't get the imakefile to work, try these.
For any computer running X11:
% cc -DX11 vine.c -lX -lm -o vine
For Sun's using pixrects:
% cc vine.c -lsunwindow -lpixrect -lm -o vine
Here are the different command line options you can use:
By default (e.g. no arguments), -e is used.
-e vines grow along the edges of the screen (default; no arguments)
-c vines grow from the center of the screen and spread *quickly*
-C draws leaves in shades of green (default is to use monochrome)
-v N grow N vines from the top of the screen (max: MAXFORKS, see below)
-h program waits for <CR> in which all vines halt (see below)
-r reverse video; black/white is inverted (no color -may be confusing)
-f fall mode. Used with -C -- shades of brown instead of green.
-D degradee -- leaf colors fade from light to dark shades (use w/ -C)
-i [N] interleaf black/white leaves 1 for each N (-N white/black)
-s N max size of leaves (default: 2)
-d device alternate display (X) or frame buffer (sun: default is /dev/fb)
-b N probability of branching (max 40)
-l N as N increases more leaves grow from each stem (max 35)
-R N 360/N different leaf rotations (default 45 degrees)
For X only
-F allow forking; off by default because X server gets confused
For Sun's only:
-w vines grow around each window on the screen (not icons; no color)
For best effects try the following:
Color displays:
% vine -C -c -s3
suns:
% vine -w -i
Experimentation with outrageous values gives other interesting effects, like:
% vine -s10 -c
Notes:
The X version uses only the following Xlib calls:
XOpenDisplay()
XSetForeground()/XSetBackground()
XDrawLine()
XFillPolygon()
XCreateGC()
XAllocColor()
XSetErrorHandler() /* see below */
XFlush() /* not really necessary */
Color vines are drawn in shades of green or brown depending on the -f switch.
Shades of these colors are gotten from trying to allocate colors in the
colormap of the root window. If there are few colors available, then
you'll get fewer shades. On my sun running MWM, I got 140 colors. I can't
seem to figure out how to get the root window to *keep* the drawing on
the window! If you move windows around, the background gets repainted to
whatever was there before the vines got written.
Multiple vines grow simultaneously by using fork() and each vine is grown
from its own process. However, X gets really confused about this and
eventually a protocol error occurs, thus the use of XSetErrorHandler().
I dump core at the location of the protocol error for debugging purposes,
but the only thing I can think of is that the separate processes are sending
requests to the server at the same time causing different GC/Window
attribute values getting set while another process expects the values
to be whatever it set them to first.
As a result, I don't allow fork()'s in the "default" case. That is,
"edge" vines (-e) doesn't fork() unless you give the -F flag to allow
forking. You will probably see the problem here. The other options
(-v -c, etc) will fork anyway, and again, you'll see the problem.
Don't try running in "sync" mode or you'll be watching forever... it's
awfully slow. I didn't provide a -sync flag, but you can uncomment
the XSynchronize() line if you like.
forks are cuaght using a SIGCHLD event handler. If you're using
VMS, then remove the #include for signal.h and the signal isn't
used.
MAX_FORKS is defined to limit the ability for the vines to runaway
with the CPU and draw vines everywhere preventing you from getting
control of your computer back. If you're not careful, vines start
growing on the desk top, the floor, furniture, everything. Altho
it's not common, "I heard some guy out in Jersey got it twice."
Name the movie that the above quote was taken from and win a Pizza!
The -h option is provided so that all forked processes can be
terminated instantly by hitting "return".
