XMonad: Hide monitor on mouse-over (config.hs)

Question

in my config.hs I use a Monitor to show wmclockmon on top of all windows like this:

myClckMonitor = monitor
    { prop = ClassName "DockApp" `And` Title "wmclockmon"
    , rect = Rectangle (1680 - 64) 0 64 64
    , persistent = False
    , name = "clock"
    }
myNewLayout = ModifiedLayout myClckMonitor $ smartBorders $ avoidStruts $ myLayout ||| noBorders Full

And additionally added it to the ignores of the manageHook.

What I want to do now is to hide the monitor when I hover (mouse over) it (and of course show it again when I leave that area). Do you have any hints how to achieve that?

Answer 1

I finally got it!

Corresponding part of my xmonad.hs:

import Data.IORef
import XMonad.Layout.Monitor

myClckMonitor = monitor
    { prop = ClassName "DockApp" `And` Title "wmclockmon"
    , rect = Rectangle (1680 - 64) 0 64 64
    , persistent = False
    , name = "clock"
    }

screenRectEventHook :: Event -> X All
screenRectEventHook CrossingEvent { ev_window = win } = do
    dpy <- asks display
    root <- asks theRoot
    (posX, posY, acc) <- io $ do
        -- queryPointer :: Display -> Window -> IO (Bool, Window, Window, Int, Int, Int, Int, Modifier)
        --    interface to the X11 library function XQueryPointer().
        (_, _, _, ix, iy, _, _, _) <- queryPointer dpy root
        r <- newIORef Nothing
        return (fromIntegral ix, fromIntegral iy, r)

    if (posY < 64 && posX > (1680 - 64))
        then do
            broadcastMessage HideMonitor >> refresh
            return (All True)
        else do
            broadcastMessage ShowMonitor >> refresh
            return (All True)
screenRectEventHook _ = return (All True)

and then register the event hook:

myEventHook e = do
    screenRectEventHook e
    return (All True)

As you can see the coordinates of my monitor are hardcoded! The question on how to re-display the clock is still open. However if you switch the Workspace or to another window it'll get visible again. That's good enough for me.