.TH xphoon "" "" "X Application"
.PC "View the phases of the moon"
xphoon  [ \-b ]  [ \-t \fIinterval ]  [ \-display \fIhose\^\fB:\fIdisplay\fB ]
.PP
.B xphoon
displays on the root window a picture of the moon in its current phase,
including the partial lighting of the dark side by reflected earthlight.
.PP
.B xphoon
does not use the Xt toolkit, so it does not recognize the standard Xt
options.
However, it does recognize the following command-line options:
.IP \fB\-b\fR
Black:
turn off the earthlight feature, and display the dark side as black.
.IP "\fB\-t \fIinterval\fR"
Normally,
.B xphoon
draws its picture on the root window, and exits.
The option
.B \-t
tells
.B xphoon
to keep running and update the picture every
.I interval
minutes.
.SH "See Also"
.B
X applications
.R
.SH Notes
The original motivation for this program was that
.B xsetroot
was too slow.
Loading a full-screen bitmap took about 15 seconds.
We made a trivial program that had
.B fullmoon.bitmap
compiled in, and it ran in less than a second.
(Incidentally, the executable was smaller than
.BR fullmoon.bitmap .)
Later we came up with the cheapmoons, the phase hacking, and
finally the earthlight.
.PP
.II "Poskanzer, Jef"
.II "Leres, Craig"
.B xphoon
was written by Jef Poskanzer (jef@rtsg.ee.lbl.gov)
and Craig Leres (leres@helios.ee.lbl.gov).
.II "Walker, John"
The moon-phase computation is from
.B moontool.c
by John Walker.
.PP
Copyright \(co 1988 by Jef Poskanzer and Craig Leres.
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.
This software is provided ``as is'' without express or implied warranty.
