wallpaper2

This script is a follow-on to one I described in an article on the Linux Journal web site, Slide Show, "Some background information for Linux desktops." The article shows how to create a slide show in the root window of your desktop.

The first version, shown in the articles, lets the user specify a regex for the size. This version allows the user to specify a minimum height and a minimum width, so that any image with height and width greater than the minima is selected. This version does arithmetic greater than or equal comparisons. So you get different shaped pictures more easily, and therefore more pictures are likely to be selected.

In addition, this version lets you count the eligible images in the path with the -c option. If you make a verbose count (-cv), the script will print out a randomized list of eligible images as well as the count.

This version gets into some pretty hairy string manipulations in BASH. Have a BASH manual handy when you read the code that extracts and analyzes the height and width, like Chapter 9 of the Advanced Bash-Scripting Guide. It was fun writing that!

#! /bin/sh
# Time-stamp: <2004-04-25 11:40:59 ccurley Wallpaper2>

# A script to run images in the root window.

# Copyright 2003 through the last date of modification Charles Curley.

# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

# You can also contact the Free Software Foundation at http://www.fsf.org/

# For more information contact the author, Charles Curley, at
# http://www.charlescurley.com/.

function oops {
  echo "$0: a script to run images in the root window."
  echo "options: -v: verbose; -w: min. width; -h: min. height; -c: count only;"
  echo " -d: duration of each image. Multiple paths accepted."
}


# How long we wait between pictures.
duration=600

# The minimum height picture we want. '' indicates all sizes
height=600

# The minimum width
width=800

# Shall we be verbose?
verbosity=0

# Shall we just count target images?
count=0

while getopts "cd:p:h:vw:" Option
do
  case $Option in
    c     ) count=1;;
    d     ) duration=$OPTARG;;
    h     ) height=$OPTARG;;
    v	  ) verbosity=1;;
    w     ) width=$OPTARG;;
    *     ) oops; exit;;   # DEFAULT
  esac
done

shift $(($OPTIND-1))

if [ -z "$*" ]; then
  oops; exit;
fi

imagepath=$*;

# This tests for the desktop we're running. It works on Red Hat or
# other systems where switchdesk and its bretheren are the standard
# way of changing the desktop. If ~/.Xclients-default isn't there, run
# "switchedesk X" where X is your desktop: gnome, KDE, TWM, etc. or
# run the GUI front end for your desktop. Or just hard code it.

# Gnome users may also take Nautilus out of their gnome session:

# gnome-session-remove nautilus

# To get it back, just run:

# nautilus &

# -iq: case insensitive, silently
grep -iq gnome ~/.Xclients-default
desktop=$?


if [ $verbosity -gt 0 ]; then
  echo imagepath = $imagepath. duration = $duration. height = $height. width = $width.
fi

# Build an array called $pictures of random pictures to display.

if [ $width -eq 0 ] || [ $height -eq 0 ] ; then
    echo 'No size limits.'
    pictures=( $(find $imagepath -type f -iname "*.jpg" | randomize) )
else
    rawpictures=( $(find $imagepath -type f -iname "*.jpg" |  xargs identify -format "%d/%f^%w^%h" | randomize ) )
    for i in "${rawpictures[@]}"; do
#      echo $i;
	p=${i%%^*};		# Get the path
	w=${i#*^};		# Get the width+height
	w=${w%%^*};		# Get the width
	h=${i##*^};		# Get the height
#       echo "$p    $h     $w"

        # If either height or width is greater, allow it.

	if [ $h -ge $height ] || [ $w -ge $width ]; then
#         echo $p
	    pictures[$j]=$p;
	    let j=$j+1;
	fi
    done

    # kill of the old array to conserve memory.

    unset rawpictures;
fi

# If there are any pictures to show, we show them.
if [ ${#pictures[@]} -gt 0 ]; then

    if [ $count -gt 0 ]; then
        echo "${#pictures[@]} images found."

	if [ $verbosity -gt 0 ]; then
	    for ele in $(seq 0 $((${#pictures[@]} - 1))); do
		echo "$ele: ${pictures[$ele]}"
	    done
	fi

    else

	if [ $verbosity -gt 0 ]; then
	    echo "I will show ${#pictures[@]} images $duration apart (default is seconds unless specified)."
	fi

	if [ $desktop == 0 ]; then
	    if [ $verbosity -gt 0 ]; then
		echo We\'re running Gnome;
	    fi

	    # Set the way we handle the background, one of
	    # [Wallpaper|Centered|Scaled|Stretched|No Picture] except
	    # that the last won't display our pictures. For
	    # information on what these do, see "1.2. Customizing the
	    # Desktop Background" under "Using the Basic Preference
	    # Tools" in the Gnome help.

	    gconftool-2 -t str -s /desktop/gnome/background/picture_options "scaled"

	    # If there are any file names in the array
	    for ele in $(seq 0 $((${#pictures[@]} - 1))); do
		if [ $verbosity -gt 0 ]; then
		    echo "$ele: ${pictures[$ele]}"
		fi
		gconftool-2 -t str -s /desktop/gnome/background/picture_filename "${pictures[$ele]}"
		sleep $duration
	    done

	else
	    if [ $verbosity -gt 0 ]; then
		echo We\'re not running Gnome
	    fi

	    echo ${pictures[@]} | xargs xv  -root -wait $duration -rmode 4

	fi
    fi
fi

randomize

You will need this script, randomize as well.

#! /usr/bin/perl

# Time-stamp: <2003-11-21 15:11:05 root randomize>

# randomize: a perl script to take stdin input, randomize it, and ship
# it out stdout. Suitable for shell scripts. Auto-detect and handle 0
# delimited arguments.

# Copyright 2003 through the last date of modification Charles Curley
# except for the subroutine fisher_yates_shuffle. fisher_yates_shuffle
# Copyright (c) 1998 Tom Christiansen, Nathan Torkington and O'Reilly
# & Associates, Inc.

# This program is free software; you can redistribute it and/or modify it
# under the terms of the GNU General Public License as published by the
# Free Software Foundation; either version 2 of the License, or (at your
# option) any later version.

# This program is distributed in the hope that it will be useful, but
# WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
# General Public License for more details.

# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA

# You can also contact the Free Software Foundation at http://www.fsf.org/

# For more information contact the author, Charles Curley, at
# http://www.charlescurley.com/.

# I wrote this so I could use ImageMagick's display program to set my
# root window every so often with one of several images, chosen at
# random. The key line of the script looks like this:

# find <path> -iname "*.jpg" -print0 | randomize | xargs -0 display -delay 60000 -window root

# (Try _that_ with that cheap operating system! :-)

# fisher_yates_shuffle ( \@array ) : generate a random
# permutation. From Perl Cookbook, Christiansen & Torkington,
# O'Reilly, 1999, page 122.

sub fisher_yates_shuffle {
    my $array = shift;
    my $i;
    for ($i = @$array; --$i; ) {
    my $j = int rand ($i+1);
    next if $i == $j;
    @$array[$i,$j] = @$array[$j,$i];
    }
}

while (<STDIN>) {
    chomp;
    push (@array, $_);
}


# If the size of the array is one, then we have one line, presumably 0
# delimited. ($#array returns the last valid index, not the size. perl
# being 0 based, the size is one larger.) You produce this with find
# by using the -print0 option. It's good for file and directory names
# with (ugh) spaces in them.

if ($#array == 0) {
    $string = @array[0];
    @array = split (/\0/,$string);
    $zeros = 1;
}


fisher_yates_shuffle (\@array);

# If the input was zero-delimited, the output will be also. Use "xargs
# -0" to further process the results.

if ($zeros) {
    $string = join ("\0", @array);
    print "$string\n";
} else {
    foreach $item (@array) {
    print "$item\n";
    }
}