Xrandr multi screen auto setup

xrandr-multi-layout.sh

#!/bin/bash
#
# Layout and Resolution
# NOTE: Equivalent settings set in xorg.conf
# NOTE: Never mind, xorg.conf is way too convoluted

SCREEN_NO="$(xrandr --query | grep '\bconnected\b' | wc -l)"


echo "Setting up $SCREEN_NO screen(s) with xrandr"

prev_width=0
prev_height=0
width_off=0
height_off=0

while read screen width height rate primary
do
    echo "Screen ${primary:-secondary}: $screen ${width}x${height}"

    [[ "$prev_width" == 0 ]] || width_off=$((width_off - width))
    [[ "$prev_height" == 0 ]] || height_off=$(((height - prev_height) / 2))

    xrandr --output "$screen" \
           --mode "${width}x${height}" \
           --pos "${width_off}x${height_off}" \
           --rate "$rate" \
           $([ "$primary" = "primary" ] && echo "--primary")

    prev_width=$width
    prev_height=$height

done <<< \
    "$(xrandr --query | perl -0ne 'while (/^(\w+-\d+) connected (primary )?.*\n\s+(\d+)x(\d+)\s+([\d\.]+)(?:\s\+\s([\d\.]+))?.*$/gm) { if ($6 eq "") { $r=$5; } else { $r=$6; } print "$1 $3 $4 $r $2\n"; }')"

# Update background
feh --no-fehbg --bg-scale $HOME/img/background