Howto show volume in Linux with On-Screen Display

libaosd Method is much prettier than the XOSD Method

libaosd Method

Requirements

• libaosd

Usage

all the following displays volume

• Increase volume
  • aosd_volume volup
• Decrease volume
  • aosd_volume voldown
• Mute volume
  • aosd_volume mute

Script

name the script, aosd_volume

#!/bin/bash

# Detect mute status and set OSD color
MUTESTATUS=$(amixer get $MIXERNAME | grep "Left:" | awk '{print $4}' | tr -d '[]')

if [ $MUTESTATUS == "off" ]; then
   OSDCOLOR=red; else
   OSDCOLOR=green
fi


# Create the "I" bar based on mixer setting and granularity
volset=$(amixer get $MIXERNAME | grep "Left:" | awk '{print $4}')

let volcounter=volset/$VOLINC
if [ $volcounter -gt $GRANULARITY ]; then
   volcounter=$GRANULARITY
fi

OSDI=""

while [ $volcounter -gt 0 ]
do
   OSDI=`echo $OSDI"I"`
   let volcounter=volcounter-1
done    

# Clean up any running aosd_cat processes
killall aosd_cat &> /dev/null

# Display the "I" bar
echo "$OSDI" | aosd_cat   -n "Arial Black $FONTSIZE" -u 1000 -o 200 -R $OSDCOLOR -S none -f 0 -y -10



# END

XOSD Method

Requirements

• XOSD
• Large Bitmap font
  • Example: 10x20 (download)

Usage

all the following displays volume

• Display volume
  • xosd_volume show
• Increase volume
  • xosd_volume incr
• Decrease volume
  • xosd_volume decr
• Mute volume
  • xosd_volume mute on/off

Script

Name the script xosd_volume

#!/bin/bash

#####################
# Config
CHANNEL='PCM'
FONT='10x20'


####################
# Code
action=$1; shift

# Unmute the volume and increase/decrease it
# Arg 1: volume change to set (1+ or 1-)
set_volume() {
    amixer sset $CHANNEL unmute &> /dev/null &
    volume=$(amixer sset $CHANNEL $1 unmute | \
             grep "Left: Playback" | \
             grep -o "\[[0-9]*%\]" | \
             tr '[%]' ' ')
}

# Get the current volume %
# No args
get_volume() {
    volume=$(amixer sget $CHANNEL | \
             grep "Left: Playback" | \
             grep -o "\[[0-9]*%\]" | \
             tr '[%]' ' ')
}

# Toggle Master volume mute on/off
# No args
mute_volume() {
    status=$(amixer sset $CHANNEL toggle | \
             grep "Left: Playback" | \
             grep -o "\[on\]\|\[off\]" | \
             tr '[]' ' ')
}

# Use xosd to show a volume guage on the screen
# Arg 1: Current volume as percent of full volume
# Arg 2: (optional) Text to show above bar
show_volume() {
    killall -9 -q osd_cat &>/dev/null

	osd_cat     --font="$FONT"     --shadow=1     --color=green     --pos=middle     --align=center     --delay=2 --text "$( [ "z$2" = "z" ] && echo Volume: $1% || echo $2 )"    --barmode=percentage --percentage=$1 
}

case "$action" in
    show)
        get_volume
		show_volume $volume 
        ;;

    incr)
        delta=1+
        set_volume $delta
        show_volume $volume 
        ;;

    decr)
        delta=1-
        set_volume $delta
        show_volume $volume 
        ;;

    mute)
        mute_volume
        case "$status" in
            off)
                show_volume 0 "Muted"
                ;;
            on)
                get_volume
                show_volume $volume
                ;;
        esac
        ;;
    *)
        echo "Usage: $0 {incr|decr|mute|show}"
        ;;
esac

External Links

• https://bbs.archlinux.org/viewtopic.php?id=41204 - original forum discussion where XOSD script is based on
• http://ubuntuforums.org/showthread.php?t=1174798 - another xosd bash script
• http://crunchbanglinux.org/forums/topic/4994/osd-for-openbox-using-aosdcat/ - a method using libaosd, for a better display, and more configurable fonts, code from this forum was used in the libaosd Method