X.H.ManageDocks: ignore struts that cover an entire screen on that screen

Ignore-this: ad7bbf10c49c9f3e938cdc3d8588e202

Imagine a screen layout like this:

  11111111
  11111111
  11111111
   222222    <--- xmobar here
   222222
   222222

When placing xmobar as indicated, the partial strut property indicates that an
entire height of screen 1 is covered by the strut, as well as a few lines at
the top of screen 2. The original code would create a screen rectangle of
negative height and wreak havoc. This patch causes such strut to be ignored on
the screen it covers entirely, resulting in the desired behaviour of a small
strut at the top of screen 2.

Please note that this semantics of _NET_WM_STRUT and _NET_WM_STRUT_PARTIAL is
different to what is in wm-spec. The "correct" thing to do would be to discard
the covered portion of screen 1 leaving two narrow areas at the sides, but
this new behaviour is probably more desirable in many cases, at least for
xmonad/xmobar users.

The correct solution of having separate _NET_WM_STRUT_PARTIAL for each
Xinerama screen was mentioned in wm-spec maillist in 2007, but has never
really been proposed, discussed and included in wm-spec. Hence this "hack".

darcs-hash:20091119145043-c9ff5-b4494537b40d2d44abec5fbcec8ea7c3c3ef1a6b.gz

1 files changed, 8 insertions, 5 deletions

diff --git a/XMonad/Hooks/ManageDocks.hs b/XMonad/Hooks/ManageDocks.hs
index 314b634..fff4a5c 100644
--- a/XMonad/Hooks/ManageDocks.hs
+++ b/XMonad/Hooks/ManageDocks.hs
@@ -236,15 +236,18 @@ c2r (x1, y1, x2, y2) = Rectangle (fi x1) (fi y1) (fi $ x2 - x1 + 1) (fi $ y2 - y
 
 reduce :: RectC -> Strut -> RectC -> RectC
 reduce (sx0, sy0, sx1, sy1) (s, n, l, h) (x0, y0, x1, y1) = case s of
-    L | p (y0, y1) -> (mx x0 sx0    , y0       , x1       , y1       )
-    R | p (y0, y1) -> (x0           , y0       , mn x1 sx1, y1       )
-    U | p (x0, x1) -> (x0           , mx y0 sy0, x1       , y1       )
-    D | p (x0, x1) -> (x0           , y0       , x1       , mn y1 sy1)
-    _              -> (x0           , y0       , x1       , y1       )
+    L | p (y0, y1) && qh x1     -> (mx x0 sx0, y0       , x1       , y1       )
+    R | p (y0, y1) && qv sx1 x0 -> (x0       , y0       , mn x1 sx1, y1       )
+    U | p (x0, x1) && qh y1     -> (x0       , mx y0 sy0, x1       , y1       )
+    D | p (x0, x1) && qv sy1 y0 -> (x0       , y0       , x1       , mn y1 sy1)
+    _                           -> (x0       , y0       , x1       , y1       )
  where
     mx a b = max a (b + n)
     mn a b = min a (b - n)
     p r = r `overlaps` (l, h)
+    -- Filter out struts that cover the entire rectangle:
+    qh d1 = n <= d1
+    qv sd1 d0 = sd1 - n >= d0
 
 -- | Do the two ranges overlap?
 --