vincentbernat.i3wm-configuration/lib/brightness.lua

-- 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