Allow a user to configure limit maximum volume output.

To do this, you need to set the `SWOB_MAX_VOLUME` variable as a
percentage, for example, `SWOB_MAX_VOLUME=120`.

2 files changed, 26 insertions, 3 deletions

diff --git a/swob-swayconfig b/swob-swayconfig
index b74c114..fd0d7a8 100644
--- a/swob-swayconfig
+++ b/swob-swayconfig
@@ -4,3 +4,9 @@ bindsym --locked XF86MonBrightnessUp	exec exec swob.sh brightness 5%+
 bindsym --locked XF86AudioLowerVolume	exec exec swob.sh volume 5%-
 bindsym --locked XF86AudioRaiseVolume	exec exec swob.sh volume 5%+
 bindsym --locked XF86AudioMute		exec exec swob.sh volume toggle
+
+# or with SWOB_MAX_VOLUME
+set $SWOB_MAX_VOLUME 120
+
+bindsym --locked XF86AudioLowerVolume	exec exec env SWOB_MAX_VOLUME=$SWOB_MAX_VOLUME swob.sh volume 5%-
+bindsym --locked XF86AudioRaiseVolume	exec exec env SWOB_MAX_VOLUME=$SWOB_MAX_VOLUME swob.sh volume 5%+
diff --git a/swob.sh b/swob.sh
index f8f5d92..d47e980 100755
--- a/swob.sh
+++ b/swob.sh
@@ -12,7 +12,7 @@ set ${BASH_VERSION:+-o pipefail} -efu
 # this is less likely.
 wobdir=$XDG_RUNTIME_DIR/swob.$WAYLAND_DISPLAY
 
-wobfifo=$wobdir/pipe wobini= SWOB_AUDIO=
+wobfifo=$wobdir/pipe wobini= SWOB_AUDIO= SWOB_MAX_VOLUME=${SWOB_MAX_VOLUME:-100}
 
 scan_confdirs() {
 	for dir in ${XDG_CONFIG_HOME:+"$XDG_CONFIG_HOME"} ~/.config /etc "${0%/*}"/../etc; do
@@ -95,6 +95,14 @@ get_audio_type() {
 	SWOB_AUDIO=alsa # default to ALSA
 }
 
+pactl_vol() {
+	pactl set-sink-"$1" @DEFAULT_SINK@ "$(echo "$2" | sed -E 's/(.*)([+-])$/\2\1/')"
+}
+
+percent_to_float() {
+	awk -v percent="$1" 'BEGIN{printf "%.1f", percent/100}'
+}
+
 set_vol() {
 	set +fu
 	get_audio_type
@@ -104,7 +112,7 @@ set_vol() {
 	pipewire)
 		case $1 in
 		toggle)	to_set=mute ;;
-		*)	to_set='volume -l 1.0' ;;
+		*)	to_set="volume -l $(percent_to_float "$SWOB_MAX_VOLUME")" ;;
 		esac
 		wpctl set-$to_set @DEFAULT_AUDIO_SINK@ "$1"
 		wpctl get-volume @DEFAULT_AUDIO_SINK@ | sed -E \
@@ -117,8 +125,17 @@ set_vol() {
 		toggle)	to_set=mute ;;
 		*)	to_set=volume ;;
 		esac
-		pactl set-sink-$to_set @DEFAULT_SINK@ "$(echo "$1" | sed -E 's/(.*)([+-])$/\2\1/')"
+		sign="${1:(-1)}"
 		percent=`pactl get-sink-volume @DEFAULT_SINK@ | sed -En 's/.* ([0-9]+)%.*/\1/p'`
+
+		if test "$to_set" = "mute" \
+			-o \( "$percent" -lt "$SWOB_MAX_VOLUME" \) \
+			-o \( "$percent" -eq "$SWOB_MAX_VOLUME" -a "$sign" = "-" \); then
+			pactl_vol "$to_set" "$1"
+		else
+			pactl set-sink-$to_set @DEFAULT_SINK@ "${SWOB_MAX_VOLUME}%"
+		fi
+
 		mute_cmd='pactl get-sink-mute @DEFAULT_SINK@'
 		mute_out=`$mute_cmd`
 		case $mute_out in