Automatic change of background image

FrenchFellow · 2016-07-23 14:29:10

Hi guys,

I wanted to add a little bling to my BL by adding an "automatic wallpaper change" feature.
So I wrote this bash script that work quite nicely :

#! /bin/bash
# wallpaper-changer.sh
# v.1
#________________________________________________________________________________________________________
# This script is based on rotate-wallpaper from Philip Newborough <corenominal@corenominal.org>. 
# It provides a wallpaper change among the files contained in the directory specified as arg1 ($1),
# every periode of time set as arg2 ($2).

# Two modes can be set as arg3 ($3) : linear (default: change as sorted in the directory) or random.
# Specifie r or R to get the random mode. 

# Use : ./ wallpaper-changer.sh /path/of/your/directory time_in_seconds mode
# example : ./ wallpaper-changer.sh ~/home/user/wallpapers 3600 r   or  ./ wallpaper-changer.sh ~/home/user/wallpapers 60

# You can launch it at startup by entering the following command in your autostart :
#    ## Launch wallpaper-changer
#    (sleep 10s && /home/user/bin/wallpaper-changer.sh ~/home/user/wallpapers 3600 r) &

# Note1 : It does not do any control of the file's type, so make sure the specified directory
# only contains image files.

# Note2 : Can't work if file's names contain any spaces.
#_______________________________________________________________________________________________________

path="$1"
# If argument 1 is empty, exit the script with error message (if launched in a terminal).
if [ -z "$1" ]; then
    echo "arg1 is empty, specify image files path"
    exit 1
fi

delay="$2"
# If argument 2 is empty, use 600 seconds as default.
if [ -z "$2" ]; then
    delay=600
fi

mode="$3"
# If argument 3 is empty, set it as l (for linear) 
if [ -z "$3" ]; then
    mode=l
fi

NUM=0

while true
do 	sleep $delay
	# list the files in the directory :
	ALIST=( `ls -w1 "$path"` )

	# Count the files :
	RANGE=${#ALIST[@]}

	if [ $mode = "r" ] || [ $mode = "R" ]; then
		# Random mode :
		NEWNUM=$NUM
			while 	[[ $NEWNUM = $NUM ]]
			do 		let NEWNUM="$RANDOM % $RANGE"
			done
		NUM=$NEWNUM
	else 
		# Linear mode :
		let NUM="$(($NUM+1)) % $RANGE"
	fi
	
	# Change the wallpaper using nitrogen :
	nitrogen --set-auto $path/${ALIST[$NUM]}

done

exit 0

I'm realy happy with these few lines.
But, to share with you guys, I tried to make a little bit more "bulletproof" version:

#! /bin/bash
# wallpaper-changer.sh
# v.2

# This script is based on rotate-wallpaper from Philip Newborough <corenominal@corenominal.org>. 
# It provides a background image change, among the files contained in the folder specified as arg1 ($1),
# every timelap set as arg2 ($2).

# Two modes can be set as arg3 ($3) : linear (default: change as sorted in the directory) or random.
# Specify r or R to get the random mode. 

# Use : ./ wallpaper-changer.sh /path/of/your/directory time_in_seconds mode
# Example : ./ wallpaper-changer.sh ~/home/user/wallpapers 3600 r   or  ./ wallpaper-changer.sh ~/home/user/wallpapers 60

# You can launch it at startup by entering the following command in your autostart file :
#    ## Launch wallpaper-changer
#    (sleep 10s && /home/"user"/bin/wallpaper-changer.sh ~/home/user/wallpapers 3600 r) &
#_______________________________________________________________________________________________________

# Change the Internal Field Separator to tab and newline only (no space) :
IFS=$'\t\n'

path="$1"
# If argument 1 is empty, exit the script with error message (if launched in a terminal).
if [ -z "$1" ]; then
    echo "arg1 is empty, specify image files path"
    exit 1
fi

delay="$2"
# If argument 2 is empty, use 600 seconds as default.
if [ -z "$2" ]; then
    delay=600
fi

mode="$3"
# If argument 3 is empty, set it as l (for linear) 
if [ -z "$3" ]; then
    mode=l
fi

NUM=0

Getnewfilenumber()
{
	if [ $mode = "r" ] || [ $mode = "R" ]; then
# Random mode :
		NEWNUM=$NUM
			while 	[[ $NEWNUM = $NUM ]]
			do 		let NEWNUM="$RANDOM % $RANGE"
			done
		NUM=$NEWNUM
	else 
# Linear mode :
		let NUM="$(($NUM+1)) % $RANGE"
	fi
}

while true
do 	sleep $delay
# List the files in the directory :
	ALIST=( `ls -w1 $path` )
# If ls retrieve an error, exit with an error message (if launched in a terminal):
	if [ -z "$ALIST" ]; then
		echo "Specified folder doesn't exist or is empty."
		exit 2
	fi
	
# Count the files :
	RANGE=${#ALIST[@]}
	
# Get a new file number :
	Getnewfilenumber
	
# Get the file extension (mime type)
	FILE_TYPE=$(file --mime-type "$path/${ALIST[$NUM]}")
	count=0
# Check if the file is an image file (.png or .jpeg). If not, get another file number :
	until 	[ "$FILE_TYPE" = "$path/${ALIST[$NUM]}: image/png" ] || \
			[ "$FILE_TYPE" = "$path/${ALIST[$NUM]}: image/jpeg" ]; do
			
			Getnewfilenumber
			FILE_TYPE=$(file --mime-type "$path/${ALIST[$NUM]}")
			count=$((count+1))

# If it can't find any image file 20 times in a row, exit
# with an error message (if launched in a terminal) :
			if [ "$count" = 20 ]; then
				echo "Can't find any image files in the directory"
				exit 3
			fi
	done

# Change the wallpaper using nitrogen (for other nitrogen commands, see nitrogen --help) :
	nitrogen --set-auto $path/${ALIST[$NUM]}
done

exit 0

Feel free to use, share and comment

porkpiehat · 2016-07-23 16:48:54

Another method, using cron: http://crunchbang.org/forums/viewtopic. … 27#p212827

And if you use feh instead of nitrogen, you can use the --randomize switch for feh to save a little work selecting a random background.

Head_on_a_Stick · 2016-07-23 16:51:50

I use https://forums.bunsenlabs.org/viewtopic … 046#p25046

porkpiehat · 2016-07-23 17:22:23

^ even simpler, and avoids parsing ls. You could also use cron to call feh and avoid having that extra sleep process (but this assumes you have cron running.)

FrenchFellow · 2016-07-23 20:08:40

Thanks for the comments.
So it can be done in one line with feh... I feel a little bit loosy

I'm not realy comfortable with cron, doesn't seem very user friendly : asuming I just want to modify the delay between two changes of wallpapers, I have to open a terminal, type the "crontab -e" command, edit the file with nano...
Thanks anyway

Last edited by FrenchFellow (2016-07-23 20:10:15)

#1 2016-07-23 14:29:10

Automatic change of background image

#2 2016-07-23 16:48:54

Re: Automatic change of background image

#3 2016-07-23 16:51:50

Re: Automatic change of background image

#4 2016-07-23 17:22:23

Re: Automatic change of background image

#5 2016-07-23 20:08:40

Re: Automatic change of background image

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