Awesome WM: LCD Brightness lib

brightness.lua

-- Handle brightness (with xbacklight)

local awful        = require("awful")
local naughty      = require("naughty")
local tonumber     = tonumber
local string       = string
local os           = os

-- A bit odd, but...
require("lib/icons")
local icons        = package.loaded["vbe/icons"]

module("snai/brightness")

local icon = icons.lookup({name = "computer-laptop",
                       type = "devices",
                       sizes = {'22x22', '16x16'}})   

local nid = nil
local function change(what)
   os.execute("xbacklight -time 50 -" .. what)
   local out = awful.util.pread("xbacklight -get")
   if not out then return end

   out = tonumber(out)

   nid = naughty.notify({ text = "Helligkeit " .. string.format("%3d %%", out),
                          font = "Free Sans Bold 12",
                          icon = icon,
                          replaces_id = nid }).id
end

function increase()
   change("inc 5")
end

function decrease()
   change("dec 5")
end