add screen brightness script for Gnome

gnome/brightness.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+
+function usage {
+  echo "usage: $0 up|down"
+}
+
+function main {
+  if [ "$#" -ne 1 ]; then
+    usage
+    exit 1
+  fi
+  
+  local method=""
+  if [ "$1" == "up" ]; then
+    method="org.gnome.SettingsDaemon.Power.Screen.StepUp"
+  elif [ "$1" == "down" ]; then
+    method="org.gnome.SettingsDaemon.Power.Screen.StepDown"
+  else
+    usage
+    exit 1
+  fi
+  dbus_result=$(gdbus call --session --dest org.gnome.SettingsDaemon.Power --object-path /org/gnome/SettingsDaemon/Power --method "$method" | tr -d "(,)")
+  level=$(echo "$dbus_result" | awk '{ printf "%f", $1 / 100 }')
+  connector=$(echo "$dbus_result" | awk '{ print $2 }')
+  gdbus call --session --dest org.gnome.Shell --object-path /org/gnome/Shell --method org.gnome.Shell.ShowOSD "{'icon': <'display-brightness-symbolic'>, 'level': <$level>, 'connector': <$connector>}"
+}
+
+main "$@"