#!/bin/sh

usage () {
	cat <<EOF>&2
Usage: ${0##*/} [OPERATION]

When no OPERATION is specified, reset the screen to the defaults.

Apply OPERATION to the X screen renderer:

  multi VIDEOPORT
  starwars
  zoomin
  zoomout

EOF
}

current=$(xrandr | sed -n "/current/{n;p;q}" | cut -f1 -d" ")
## Other unreliable options:
# xrandr | grep -m1 "\<connected\>" | cut -f1 -d" "
# xrandr | awk 'NR==2 {print $1; exit}'

if [ $# -eq 0 ]; then
	xrandr --output "$current" --auto --transform none --brightness 1 && \
		xrandr -s "$(xrandr | awk '/^ / {print $1;exit}')"
	exit
fi

case "$1" in
multi)
	[ $# -lt 2 ] && usage && exit 1
	xrandr --output "$2" --auto --right-of "$current" ;;
starwars)
	xrandr --output "$current" --transform 1.24,0.16,-124,0,1.24,0,0,0.000316,1 ;;
zoomin)
	xrandr --output "$current" --scale 0.8x0.8 ;;
zoomout)
	xrandr --output "$current" --scale 1.2x1.2 ;;
*)
	usage;;
esac

## Old code.
# xscreen () {
# 	## Does not work?
# 	cvt $1 $2
# 	echo  "$(cvt $1 $2 | tail -1 | cut -d' ' -f2-)"
# 	xrandr --newmode "$(cvt $1 $2 | tail -1 | cut -d' ' -f2-)"
# }