added flash focus

module/flash_focus.lua

@@ -0,0 +1,32 @@
+local gears = require("gears")
+local beautiful = require("beautiful")
+
+local op = beautiful.flash_focus_start_opacity or 0.6
+local stp = beautiful.flash_focus_step or 0.01
+
+local flashfocus = function(c)
+    if c then
+        c.opacity = op
+        local q = op
+        local g = gears.timer {
+            timeout = stp,
+            call_now = false,
+            autostart = true
+        }
+
+        g:connect_signal("timeout", function()
+            if q >= 1 then
+                c.opacity = 1
+                g:stop()
+            else
+                c.opacity = q
+                q = q + stp
+            end
+        end)
+    end
+end
+
+local enable = function() client.connect_signal("focus", flashfocus) end
+local disable = function() client.disconnect_signal("focus", flashfocus) end
+
+return {enable = enable, disable = disable}

module/init.lua

@@ -1,4 +1,5 @@
 return {
     window_swallowing = require("bling.module.window_swallowing"),
-    tiled_wallpaper   = require("bling.module.tiled_wallpaper")
+    tiled_wallpaper = require("bling.module.tiled_wallpaper"),
+    flash_focus = require("bling.module.flash_focus")
 }