scripts/dpi: add DPI live change script

scripts/dpi

@@ -0,0 +1,30 @@
+#!/bin/sh
+set -e
+
+# Based on https://github.com/vincentbernat/awesome-configuration/blob/master/bin/xsettingsd-setup
+
+dpi=$1
+
+if [ -z "$1" ]; then
+    >&2 printf "Usage\n\t%s: <dpi>" "$(basename "$0")"
+    exit 1
+fi
+
+CONF_DIR="${XDG_CONFIG_HOME:-$HOME/.config}/xsettingsd"
+
+# Build xsettingsd.local
+{
+    cat $CONF_DIR/xsettingsd.conf 2>/dev/null || true
+    echo Xft/DPI $(( $dpi*1024 ))
+    echo Gdk/WindowScalingFactor $(( $dpi/96 ))
+    echo Gdk/UnscaledDPI $(( $dpi*1024/($dpi/96) ))
+} > $CONF_DIR/xsettingsd.local
+
+pid=$(xprop -name xsettingsd _NET_WM_PID 2> /dev/null | awk '{print $NF}')
+if [ -z "$pid" ]; then
+    xsettingsd -c $CONF_DIR/xsettingsd.local &
+else
+    kill -HUP $pid
+fi
+
+echo Xft.dpi: $dpi | xrdb -merge