Add an ad-hoc screen switching system

Write a script to switch monitors, and make Polybar play nice with it

i3/config

@@ -96,7 +96,7 @@ bindsym XF86MyComputer exec $filemanager
 
 # change display layout
 bindsym $mod+XF86Display exec arandr
-bindsym XF86Display      exec --no-startup-id $HOME/.config/i3/enable-only-hdmi.sh
+bindsym XF86Display      exec --no-startup-id $HOME/.config/i3/screens.sh
 
 
 #############################

i3/enable-only-hdmi.sh

@@ -1,6 +0,0 @@
-#!/bin/bash
-
-xrandr --output HDMI-1 --auto &&
-	xrandr --output eDP-1 --off &&
-	$(dirname "$0")/../polybar/launch.sh &&
-	i3-msg 'workspace 1'

i3/screen_config

@@ -0,0 +1,5 @@
+#!/bin/false
+
+builtin="eDP-1"
+ext1="HDMI-1"
+ext2="VGA-1"

i3/screens.sh

@@ -0,0 +1,135 @@
+#!/bin/bash
+
+scriptdir="$(dirname "$0")"
+
+source "$scriptdir/screen_config"
+[[ -n $builtin ]] || { echo "builtin empty"; exit 1; }
+[[ -n $ext1 ]]    || { echo "ext1 empty";    exit 1; }
+[[ -n $ext2 ]]    || { echo "ext2 empty";    exit 1; }
+
+xq="$(xrandr --query)"
+xlm="$(xrandr --listmonitors)"
+
+card() { echo "$xq"  | grep -qF "$1";           }
+conn() { echo "$xq"  | grep -qF "$1 connected"; }
+actv() { echo "$xlm" | grep -qF "$1";           }
+
+should_exist() {
+	for i in "$@"; do
+		card "$i" || { echo "$i not on video card, refusing to do anything"; exit 1; }
+	done
+}
+should_exist "$builtin" "$ext1" "$ext2"
+
+trigger_change_and_exit() {
+	"$scriptdir/../polybar/launch.sh" & disown
+	exit
+}
+
+single_screen() {
+	one="$1"
+	off1="$2"
+	off2="$3"
+
+	xrandr \
+		--output "$one" --auto --primary \
+		--output "$off1" --off \
+		--output "$off2" --off
+	notify-send "Only $screen connected" "Disabled all outputs except for $screen."
+	trigger_change_and_exit
+}
+
+toggle_two_screens() {
+	one="$1"
+	two="$2"
+	off="$3"
+
+	if actv "$one" && actv "$two"; then
+		xrandr \
+			--output "$one" --off \
+			--output "$two" --auto --primary \
+			--output "$off" --off
+	elif ! actv "$one" && actv "$two"; then
+		xrandr \
+			--output "$one" --auto --primary \
+			--output "$two" --off \
+			--output "$off" --off
+	else
+		xrandr \
+			--output "$one" --auto --primary \
+			--output "$two" --auto --left-of "$builtin" \
+			--output "$off" --off
+	fi
+	trigger_change_and_exit
+}
+
+toggle_three_screens() {
+	one="$1"
+	two="$2"
+	three="$3"
+
+	if actv "$one" && actv "$two" && actv "$three"; then
+		xrandr \
+			--output "$one" --off \
+			--output "$two" --auto --primary \
+			--output "$three" --auto --left-of "$two"
+	elif ! actv "$one" && actv "$two" && actv "$three"; then
+		xrandr \
+			--output "$one" --auto --primary \
+			--output "$two" --off \
+			--output "$three" --auto --left-of "$one"
+	elif actv "$one" && ! actv "$two" && actv "$three"; then
+		xrandr \
+			--output "$one" --auto --primary \
+			--output "$two" --auto --left-of "$one" \
+			--output "$three" --off
+	elif actv "$one" && actv "$two" && ! actv "$three"; then
+		xrandr \
+			--output "$one" --auto --primary \
+			--output "$two" --off \
+			--output "$three" --off
+	elif actv "$one" && ! actv "$two" && ! actv "$three"; then
+		xrandr \
+			--output "$one" --off \
+			--output "$two" --auto --primary \
+			--output "$three" --off
+	elif ! actv "$one" && actv "$two" && ! actv "$three"; then
+		xrandr \
+			--output "$one" --off \
+			--output "$two" --off \
+			--output "$three" --auto --primary
+	else
+		xrandr \
+			--output "$one" --auto --primary \
+			--output "$two" --auto --left-of "$one" \
+			--output "$three" --auto --left-of "$two"
+	fi
+	trigger_change_and_exit
+}
+
+# Only builtin connected
+if conn "$builtin" && ! conn "$ext1" && ! conn "$ext2"; then
+	single_screen "$builtin" "$ext1" "$ext2"
+fi
+
+# Only builtin and ext1 connected
+if conn "$builtin" && conn "$ext1" && ! conn "$ext2"; then
+	toggle_two_screens "$builtin" "$ext1" "$ext2"
+fi
+
+# Only builtin and ext2 connected
+if conn "$builtin" && ! conn "$ext1" && conn "$ext2"; then
+	toggle_two_screens "$builtin" "$ext2" "$ext1"
+fi
+
+# Builtin, ext1 and ext2 connected
+if conn "$builtin" && conn "$ext1" && conn "$ext2"; then
+	toggle_three_screens "$builtin" "$ext1" "$ext2"
+fi
+
+# Other cases: something's wrong, try enabling all displays
+xrandr \
+	--output "$builtin" --auto --primary \
+	--output "$ext1" --auto \
+	--output "$ext2" --auto
+

polybar/config.ini

@@ -23,7 +23,7 @@ foreground-alert    = #ff4e4e
 ; I don't use this at the moment
 enable-ipc = false
 
-;monitor = ${env:MONITOR:HDMI-1}
+monitor = ${env:MONITOR:eDP-1}
 width = 100%
 height = 27
 fixed-center = true

polybar/launch.sh

@@ -13,6 +13,11 @@ while pgrep -u $UID -x polybar >/dev/null; do sleep 1; done
 	source "$(dirname "$0")"/secrets.sh
 	set +o allexport
 
+	# Get the primary monitor, or else just any active monitor
+	MONITOR="$(xrandr | grep " connected primary" | head -n1 | cut -d ' ' -f1)"
+	[[ -n $MONITOR ]] || MONITOR="$(xrandr | grep " connected" | head -n1 | cut -d ' ' -f1)"
+	[[ -n $MONITOR ]] && export MONITOR
+
 	polybar --config="$HOME/.config/polybar/config.ini" midbard
 )