ZUFALL

Section: User Commands (1)
Updated: Dec 2007

NAME

zufall - a simple program to change the background periodically.

SYNOPSIS

zufall [options] /path/to/imagedir-or-file [/path/to/imagedir-or-file]

DESCRIPTION

zufall takes one or more directories with images as a parameter and sets a randomly chosen image as background. If there is a border remaining, its color is the average color of two corners of the image. This mostly fits the image very well. It is also possible to execute a command when the image changes.

zufall does not work if the root window is hidden by another program that does not pick up changes on the root window.

OPTIONS

-d, --delay=delay

number of seconds an image is shown (default 900)

-s --maxscale=percent

maximum percent the image will be scaled (default 150)

-b --minborder=pixel

ignore --maxscale if the remaining border would be smaller than pixel (default 100)

-m --minsize=kilobyte

only show images bigger than kilobyte. A size of 0 shows all images (default 0)

-l --list=file

load list of images from file

* the format of the file is one directory or file per line

* file can also be a collection from gqview

* if file is -, the list will be read from stdin

-S --sequential

don't randomize the imagelist. This is useful with -l, or if you want to see the images directory-wise.

-c --command=command

execute command on every picture change. Within command

%c: gets replaced with the background-color
%i: gets replaced with the image-filename
%w: gets replaced with the scaled width
%h: gets replaced with the scaled height
%%: gets replaced with %

Mind the quoting, the command is interpreted by the shell!

-n --no-set

don't set the background (but execute command if given)

-p --passes=passes

exit after given number of images

--help

display help and exit

--version

output version information and exit

SIGNALS

HUP: change background
USR1: output some info. Note that the memory shown is only the memory that is used for the paths. There is additional memory used by the X-server to hold the image.
TERM: exit

GNOME

zufall can not be used directly to set the background in gnome. This is because nautilus covers the root window, so the background can not be seen. Additionally nautilus will crash.

To randomize the background in Gnome, the wrapper script zufall-gnome exists, which uses gconftool-2 to set the background. It takes the same parameters as zufall. Note that the parameters affecting the size of the background image will not work when using zufall-gnome.

XFCE

If zufall is started within Xfce, xfdesktop will give up the desktop completely (including desktop menus), but no background image will be shown. However, Xfce is able to change to a random background that it gets from a file by itself. With this mechanism zufall could be used to manage the picture changes, but there seems to be no good solution to set the desktop color and size of the image with zufall.

EXAMPLES

To try out what the -c option does:

zufall /path/to/images -n -c 'echo "picture: %i color: %c scaled res: %wx%h"'

To append the name of the current image to a file:

zufall /path/to/images -c 'echo "%i" >> /tmp/imagehistory'

To view random images in gqview:

zufall /path/to/images -n -c 'gqview -r "%i"'

To get a list of files from another program (GNU-find in this case)

find /path/to/images -type f -size +512k -not -wholename '/path/to/bad/images/*' | zufall -l -

TIP

Bind pkill -1 zufall to a key or put it in a launcher to change the background with a keypress.

BUGS

How portable is it? Please tell me if you can('t) get it to run under anything else than GNU/Linux or FreeBSD!
Please send bug reports and feedback to the author.

AUTHOR

Moritz Orbach <zufall@apfelboymchen.homeunix.net>