XMonad.Actions.GridSelect: added gs_cancelOnEmptyClick field

In the original code, when a GridSelect is shown, user has to use keyboard to
cancel it (ESC key by default). With this field added, when it is set to True,
mouse click on empty space can cancel the GridSelect.

CHANGES.md

@@ -20,6 +20,14 @@
       myFunc` should be changed to `historyCompletionP myConf myFunc`.
       If not `myConf` is lying around, `def` can be used instead.
 
+  * `XMonad.Actions.GridSelect`
+
+    - Added `gs_cancelOnEmptyClick` field in `GSConfig`. Previously when a
+      GridSelect is shown, user has to use keyboard to cancel it (ESC key by
+      default). With this field added, when it is set to True, mouse click on
+      empty space can cancel the GridSelect. when set to False (the default),
+      the old behavior is preserved.
+
 ### New Modules
 
   * `XMonad.Actions.Profiles`

XMonad/Actions/GridSelect.hs

@@ -179,6 +179,7 @@ import qualified Data.List.NonEmpty as NE
 -- >    { gs_cellheight = 30
 -- >    , gs_cellwidth = 100
 -- >    , gs_navigate = myNavigation
+-- >    , gs_cancelOnEmptyClick = True  -- cancel grid when click on empty space
 -- >    }
 
 -- $screenshots
@@ -203,10 +204,14 @@ data GSConfig a = GSConfig {
       gs_colorizer :: a -> Bool -> X (String, String),
       gs_font :: String,
       gs_navigate :: TwoD a (Maybe a),
+                                -- ^ Customize key bindings for a GridSelect
       gs_rearranger :: Rearranger a,
       gs_originFractX :: Double,
       gs_originFractY :: Double,
-      gs_bordercolor :: String
+      gs_bordercolor :: String,
+      gs_cancelOnEmptyClick :: Bool
+                                -- ^ When True, click on empty space will
+                                -- cancel GridSelect
 }
 
 -- | That is 'fromClassName' if you are selecting a 'Window', or
@@ -386,13 +391,18 @@ updateElementsWithColorizer colorizer elementmap = do
 stdHandle :: Event -> TwoD a (Maybe a) -> TwoD a (Maybe a)
 stdHandle ButtonEvent{ ev_event_type = t, ev_x = x, ev_y = y } contEventloop
     | t == buttonRelease = do
-        s@TwoDState { td_paneX = px, td_paneY = py,
-                         td_gsconfig = (GSConfig ch cw _ _ _ _ _ _ _ _) } <- get
-        let gridX = (fi x - (px - cw) `div` 2) `div` cw
+        s@TwoDState { td_paneX = px, td_paneY = py, td_gsconfig = gsconfig } <- get
+        let ch = gs_cellheight gsconfig
+            cw = gs_cellwidth gsconfig
+            gridX = (fi x - (px - cw) `div` 2) `div` cw
             gridY = (fi y - (py - ch) `div` 2) `div` ch
         case lookup (gridX,gridY) (td_elementmap s) of
              Just (_,el) -> return (Just el)
-             Nothing -> contEventloop
+             Nothing -> if gs_cancelOnEmptyClick gsconfig
+               then
+                 return Nothing
+               else
+                 contEventloop
     | otherwise = contEventloop
 
 stdHandle ExposeEvent{} contEventloop = updateAllElements >> contEventloop
@@ -648,7 +658,7 @@ gridselect gsconfig elements =
     liftIO $ mapWindow dpy win
     liftIO $ selectInput dpy win (exposureMask .|. keyPressMask .|. buttonReleaseMask)
     status <- io $ grabKeyboard dpy win True grabModeAsync grabModeAsync currentTime
-    io $ grabPointer dpy win True buttonReleaseMask grabModeAsync grabModeAsync none none currentTime
+    _ <- io $ grabPointer dpy win True buttonReleaseMask grabModeAsync grabModeAsync none none currentTime
     font <- initXMF (gs_font gsconfig)
     let screenWidth = toInteger $ rect_width scr
         screenHeight = toInteger $ rect_height scr
@@ -706,7 +716,7 @@ decorateName' w = do
 
 -- | Builds a default gs config from a colorizer function.
 buildDefaultGSConfig :: (a -> Bool -> X (String,String)) -> GSConfig a
-buildDefaultGSConfig col = GSConfig 50 130 10 col "xft:Sans-8" defaultNavigation noRearranger (1/2) (1/2) "white"
+buildDefaultGSConfig col = GSConfig 50 130 10 col "xft:Sans-8" defaultNavigation noRearranger (1/2) (1/2) "white" False
 
 -- | Brings selected window to the current workspace.
 bringSelected :: GSConfig Window -> X ()