.TH bggen "" "" "X Application"
.PC "Generate colored backgrounds on X11 displays"
.fi
\fBbggen
[\-w \fIwidth\^\fB]
[\-s \fIsize\^\fB]
[\-b \fIbits\^\fB
\fIr1 g1 b1\fR \fB[\fIr2 g2 b2 \fB... \fIrn gn bn\^\fB]\fR
.PP
The program
.B bggen
generates a small PPM file that displays a vertical, colored stripe on
your display's root window.
The output of
.B bggen
can be passed to a program like
.B xv
to generate a background for your screen.
.PP
The top of the stripe that
.B bggen
creates is in the color set by arguments
\fIr1\fR,\fIg1\fR,\fIb1\fR, where
.I r1
sets the red gun,
.I g1
the green gun,
and
.I b1
the blue gun.
Values must range between zero and 255, inclusive, where zero
indicates ``off'' and 255 means ``fully on''.
The bottom of the stripe is in color \fIrn\fR,\fIgn\fR,\fIbn\fR.
Intermediate colors are
interpolated between these colors.
If you specify more than two colors, the
stripe passes through all the specified colors, in the order specified.
.PP
The command-line option
.B \-b
specifies the number of significant bits in the output
color specifications.
It must range between one and eight, inclusive; the default is eight.
By lowering the number of significant bits, you limit the number of colors
used, and so increase the granularity of the colors.
.PP
Command-line options
.B \-w
and
.B \-s
give, respectively, the width and height of the stripe, in pixels.
The default height is 1,024 pixels, which should be as tall as your display.  
If your display is higher or shorter than that, you must specify its
actual height; otherwise you will get a bizarre repeating effect.
Note that if you specify small values of
.BR \-s ,
you can get some interesting effects.
Option
.B \-w
argument has been added to improve the performance of various
stippling algorithms (as in
.BR xv ).
Try using the option
.B "\-w 16"
to see what is meant.
.SH Examples
The following gives examples of backgrounds generated with
.BR bggen .
.PP
Light Blue to Dark Blue:
.DM
	bggen 100 100 255  50 50 150  | xv -ro -q -s
.DE
.PP
RGB Rainbow:
.DM
	bggen 0 0 255  0 255 0  255 0 0 | xv -ro -q -s
.DE
.PP
Green Cylinders:
.DM
	bggen 0 0 0  0 255 0  0 0 0 -s 128 | xv -ro -q -s
.DE
.PP
Blue to Magenta:
.DM
	bggen 0 0 255  200 0 100 | xv -ro -q -s
.DE
.PP
Full Rainbow:
.DM
	bggen 0 0 255  0 255 255  0 255 0  255 255 0  255 0 0 | xv -ro -q -s
.DE
.PP
Repeating Rainbow:
.DM
	bggen 0 0 255  0 255 255  0 255 0  255 255 0  255 0 0 
	      255 0 255  0 0 255 -s 256 | xv -ro -q -s
.DE
.SH "See Also"
.B
X applications,
xv
.R
.SH Notes
.II "Bradley, John"
.B bggen
was written by John Bradley (bradley@cis.upenn.edu).

