grav - draws a simple orbital simulation

       Greg Bowering <gb@pobox.com>, 1993.

       Ability to run standalone or with xscreensaver added by Jamie Zawinski <jwz@jwz.org>, 10-May-97.

X Version 11                                   6.08 (10-Oct-2023)                                       grav(6x)

       Copyright © 1993 by Greg Bowering.

       Permission  to  use, copy, modify, and distribute this software and its documentation for any purpose and
       without fee is hereby granted, provided that the above copyright notice appear in  all  copies  and  that
       both that copyright notice and this permission notice appear in supporting documentation.

       The grav program draws a simple orbital simulation

DISPLAY to get the default host and display number.

       XENVIRONMENT
               to get the  name  of  a  resource  file  that  overrides  the  global  resources  stored  in  the
               RESOURCE_MANAGER property.

       XSCREENSAVER_WINDOW
               The window ID to use with --root.

       grav - draws a simple orbital simulation

grav accepts the following options:

       --window
               Draw on a newly-created window.  This is the default.

       --root  Draw on the root window.

       --window-idnumber
               Draw on the specified window.

       --mono  If on a color display, pretend we're on a monochrome display.

       --install
               Install a private colormap for the window.

       --visualvisual
               Specify  which  visual  to  use.   Legal  values are the name of a visual class, or the id number
               (decimal or hex) of a specific visual.

       --ncolorsinteger
               How many colors should be used (if possible).  Default 64.  The colors are chosen randomly.

       --countinteger
               Default 12.

       --decay--no-decay
               Whether orbits should decay.

       --trail--no-trail
               Whether the objects should leave trails behind them (makes it look vaguely like a cloud-chamber.

       --fps   Display the current frame rate and CPU load.

X(1), xscreensaver(1), xlock(1)

grav  [--display  host:display.screen]  [--foreground  color]  [--background  color]  [--window] [--root]
       [--window-id number][--mono] [--install] [--visual visual]  [--ncolors  integer]  [--delay  microseconds]
       [--count integer] [--decay] [--no-decay] [--trail] [--no-trail]

       [--fps]