Add new config value, defaultMenuGap, for specifying a gap for a status bar

By default, it is 0 (set in Config.hs), but set this to a pixel count to
get a permanent gap at the top of the screen. You can then at startup
launch dzen, and it will run in this gap, and not be obscured by other
windows.

Perfect for a persistant status bar.

Config.hs

@@ -49,6 +49,10 @@ defaultDelta = 3%100
 defaultWindowsInMaster :: Int
 defaultWindowsInMaster = 1
 
+-- Default width of gap at top of screen for a menu bar (e.g. 16)
+defaultMenuGap :: Int
+defaultMenuGap = 0
+
 -- numlock handling:
 --
 -- The mask for the numlock key. You may need to change this on some systems.

Config.hs-boot

@@ -1,3 +1,4 @@
 module Config where
 import Graphics.X11.Xlib.Types (Dimension)
 borderWidth :: Dimension
+defaultMenuGap :: Int

Operations.hs

@@ -15,7 +15,7 @@ module Operations where
 
 import XMonad
 import qualified StackSet as W
-import {-# SOURCE #-} Config (borderWidth)
+import {-# SOURCE #-} Config (borderWidth,defaultMenuGap)
 
 import Data.Maybe
 import Data.List            (genericIndex, intersectBy)
@@ -131,8 +131,10 @@ refresh = do
         let n      = W.tag (W.workspace w)
             this   = W.view n ws
             Just l = fmap fst $ M.lookup n fls
+            Rectangle sx sy sw sh = genericIndex xinesc (W.screen w)
         -- now tile the windows on this workspace
-        rs <- doLayout l (genericIndex xinesc (W.screen w)) (W.index this)
+        rs <- doLayout l (Rectangle sx (sy + fromIntegral defaultMenuGap)
+                                    sw (sh - fromIntegral defaultMenuGap)) (W.index this)
         mapM_ (\(win,rect) -> io (tileWindow d win rect)) rs
 
         -- and raise the focused window if there is one.