Automatically select screen

scr.sh

#!/bin/bash

# Usage: scr [local|external|clone]
#        (no option) → try external, else local
#        local       → local display
#        external    → external + local if closed, else external only
#        clone       → same content, local display scaled to fit external

export DISPLAY=`ck-list-sessions|grep 'x11-display = '|sed "s/.*\(:[0-9]\)'/\1/"`

LOCAL=LVDS1
WIDTH=
HEIGHT=

screensize () {
    splitsize `xrandr -q --current|grep "^$1" -A1|tail -n1|sed "s/\([0-9]\+\)x\([0-9]\+\).*/\1x\2/"`
}

splitsize () {
    WIDTH=`echo $1|cut -dx -f1`
    HEIGHT=`echo $1|cut -dx -f2`
}

# figure out whether an external monitor is connected
EXTERNAL=`xrandr --current|grep ' connected'|cut -d' ' -f1|grep -v $LOCAL|head -n1`
SCALE='1x1'

if test -n "$EXTERNAL"; then
    MODE=external
    cat /proc/acpi/button/lid/LID/state | grep -q closed && MODE=external-only

    screensize $LOCAL
    w1=$WIDTH
    h1=$HEIGHT

    screensize $EXTERNAL
    w2=$WIDTH
    h2=$HEIGHT

    SCALE=`echo "s1=$w2/$w1;s2=$h2/$h1;if(s1>s2) s1 else s2"|bc -l`
    SCALEX=`echo "$w2/$w1"|bc -l`
    SCALEY=`echo "$h2/$h1"|bc -l`
else
# no external output connected
    MODE=local
fi


case $1 in
    external)
	if test -n "$EXTERNAL";then
	    MODE=external
	else
	    echo "No external screen found."
	    exit 1
	fi
	;;
    clone)
	if test -n "$EXTERNAL";then
	    MODE=clone
	else
	    echo "No external screen found."
	    exit 1
	fi
	;;
    local)
	MODE=local
esac

case $MODE in
    external-only)
	xrandr --output $LOCAL --off --output $EXTERNAL --auto --scale 1x1
	;;
    external)
	xrandr --output $LOCAL --auto --scale 1x1 --output $EXTERNAL --auto --scale 1x1 --left-of $LOCAL
	;;
    clone)
	xrandr --output $LOCAL --auto --scale ${SCALEX}x${SCALEY} --output $EXTERNAL --auto --same-as $LOCAL
	;;
    local)
	xrandr --output $LOCAL --auto --scale 1x1 --output VGA1 --off --output HDMI1 --off --output DP1 --off --output DP2 --off --output DP3 --off
	;;
esac

xrefresh