SETBACK(1) X Version 11 SETBACK(1)
27 November 1989
NAME
setback - Set background to image
SYNOPSIS
setback file [ options ]
DESCRIPTION
setback tiles the screen background with an image. If the image
requires more colors than are available for private use by an X11
client, it displays a quantized copy of the image which uses a smaller
number of colors.
When appropriate, setback may convert the image automatically to a
different representation to suit the screen's default visual. This
may involve converting in either direction between RGB and color-
mapped format, and it may involve quantizing the image to force it to
use only the maximum number of colors available. Similarly, it may
convert color to grayscale or monochrome (dithered black and white).
The file argument can be a specific filename or a "base" filename for
an image. If file cannot be opened, setback tries file.Z, file.p, and
file.p.Z.
Any file whose names ends with .Z is presumed to be in compressed
format.
OPTIONS
This program accepts the standard options listed below. They are
listed as command line options, but can also be supplied as X
resources; for example, "-force monochrome" on the command line has
the same effect as "dispimg.force: monochrome".
-colorinstances scope
-colorinstances private selects use of privately allocated
(read/write) colors, -colorinstances shared selects use of shared
(read only) colors. Private colors cannot be shared with other
clients using the same color map, but they allow better image
quality than shared colors.
-colormap scope
-colormap private selects use of a private color map. -colormap
shared selects shared use of a default color map. A private
color map allows the best possible color rendition for the image,
but may cause annoying color changes on the screen as the cursor
moves into or out of the image's window.
-display displayname
Name of X server to use, including screen number.
-force restriction
-force grayscale forces conversion of a color image to grayscale.
- 1 - Formatted: November 4, 2025
SETBACK(1) X Version 11 SETBACK(1)
27 November 1989
-force monochrome forces conversion of a color or grayscale image
to monochrome (dithered black and white). -force nothing retains
as much of the image's original data as possible.
-maxcolors n
This specifies the maximum number of colors (2 - 256) to be
retained in a color-mapped image. The maximum depends on how
many colors the display hardware supports.
AUTHOR
Paul Raveling, USC Information Sciences Institute
- 2 - Formatted: November 4, 2025
