lib: add notifications for brightness change

lib/brightness.lua

@@ -0,0 +1,32 @@
+-- Handle brightness (with xbacklight)
+
+local awful        = require("awful")
+local naughty      = require("naughty")
+local tonumber     = tonumber
+local string       = string
+local os           = os
+
+module("vbe/brightness")
+
+local nid = nil
+local function change(what)
+   -- We don't really change the brightness, just report the change...
+   local out = awful.util.pread("xbacklight -get")
+   if not out then return end
+
+   out = tonumber(out)
+   local icon = "/usr/share/icons/HighContrast/32x32/status/display-brightness.png"
+
+   nid = naughty.notify({ text = string.format("%3d %%", out),
+			  icon = icon,
+			  font = "Free Sans Bold 24",
+			  replaces_id = nid }).id
+end
+
+function increase()
+   change("+ 5")
+end
+
+function decrease()
+   change("- 5")
+end