Track mouse position via events received

XMonad/Core.hs

@@ -70,6 +70,9 @@ data XConf = XConf
     , buttonActions :: !(M.Map (KeyMask, Button) (Window -> X ()))
                                       -- ^ a mapping of button presses to actions
     , mouseFocused :: !Bool           -- ^ was refocus caused by mouse action?
+    , mousePosition :: !(Maybe (Position, Position))
+                                      -- ^ position of the mouse according to
+                                      -- the event currently being processed
     }
 
 -- todo, better name

XMonad/Main.hsc

@@ -99,7 +99,8 @@ xmonad initxmc = do
             , focusedBorder = fbc
             , keyActions    = keys xmc xmc
             , buttonActions = mouseBindings xmc xmc
-            , mouseFocused  = False }
+            , mouseFocused  = False
+            , mousePosition = Nothing }
         st = XState
             { windowset     = initialWinset
             , mapped        = S.empty
@@ -136,10 +137,19 @@ xmonad initxmc = do
             userCode $ startupHook initxmc
 
             -- main loop, for all you HOF/recursion fans out there.
-            forever_ $ handle =<< io (nextEvent dpy e >> getEvent e)
+            forever_ $ prehandle =<< io (nextEvent dpy e >> getEvent e)
 
     return ()
-      where forever_ a = a >> forever_ a
+      where
+        forever_ a = a >> forever_ a
+
+        -- if the event gives us the position of the pointer, set mousePosition
+        prehandle e = let mouse = do guard (ev_event_type e `elem` evs)
+                                     return (fromIntegral (ev_x_root e)
+                                            ,fromIntegral (ev_y_root e))
+                      in local (\c -> c { mousePosition = mouse }) (handle e)
+        evs = [ keyPress, keyRelease, enterNotify, leaveNotify
+              , buttonPress, buttonRelease]
 
 
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