.\" Copyright (c) 1986, University of Utah
.TH RLEBG 1 "November 12, 1986" 1
.UC 4 
.SH NAME
rlebg \- generate simple backgrounds
.SH SYNOPSIS
.B rlebg
[
.B \-l
] [
.B \-v
[
.I top
[
.I bottom
] ] ] [
.B \-s
.I "xsize ysize"
] [ 
.B \-o
.I outfile
]
.I "red green blue"
[
.I alpha
]
.SH DESCRIPTION
.IR rlebg
generates a simple background.  These are typically used for compositing
below other images.  The values
.I "red green blue"
specify the pixel values (between 0 and 255) the background will have.
If 
.I alpha
is not specified, it defaults to 255 (full coverage).
.IR rlebg
generates both constant backgrounds and backgrounds with continuous 
ramps. 
.SH OPTIONS
.TP
.BI \-s " xsize ysize"
This is the size of the background image.  The default is 512\(mu480.
.TP
.B \-l
Generate a linear ramp of pixel values.  If no ramp flag is given, 
.IR rlebg 
generates a constant background. 
.TP
.BI \-v " top bottom"
Generate a variable ramp, using a quadratic function (this looks best
with gamma corrected images).
.I top
and
.I bottom
are the fractions of the full color values at the top and bottom of the image.
The defaults are 1.0 0.1, respectively.  If both 
.B \-v
and
.B \-l
are given, then a linear ramp function is used instead of a quadratic ramp.
.TP
.BI \-o " outfile"
If specified, the output will be written to this file.  If 
.I outfile
is "\-", or if it is not specified, the output will be written to the
standard output stream.
.LP
.SH SEE ALSO
.IR rlesetbg (1),
.IR urt (1),
.IR RLE (5).
.SH AUTHOR
Rod Bogart