vanadium/xmonad: use event handling to set master pane count

nix/configurations/vanadium/home/xmonad/leanamonad.cabal

@@ -25,6 +25,7 @@ library
   hs-source-dirs: lib
   exposed-modules:
     XMonad.Layout.Reflect.Message
+    XMonad.Layout.SetMasterNTall
     Data.Char.Greek
 
 executable leanamonad

nix/configurations/vanadium/home/xmonad/lib/XMonad/Layout/SetMasterNTall.hs

@@ -0,0 +1,30 @@
+{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}
+
+-- Wraps ResizableTall, allows setting master count to a number directly
+module XMonad.Layout.SetMasterNTall
+  ( SetMasterNTall(..)
+  , SetMasterN(..)
+  ) where
+
+import XMonad
+import qualified XMonad.StackSet as W
+import XMonad.Layout.ResizableTile
+
+-- Message
+data SetMasterN = SetMasterN Int
+instance Message SetMasterN
+
+-- Layout
+newtype SetMasterNTall a = SetMasterNTall { unSetMasterNTall :: ResizableTall a }
+    deriving (Read, Show)
+
+instance LayoutClass SetMasterNTall a where
+  runLayout (W.Workspace t l s) =
+    let ws' = W.Workspace t (unSetMasterNTall l) s
+    in  (fmap . fmap . fmap) SetMasterNTall . runLayout ws'
+
+  handleMessage (SetMasterNTall l@(ResizableTall _n0 d f s)) mess
+      | Just (SetMasterN n) <- fromMessage mess = pure $ Just $ SetMasterNTall $ ResizableTall n d f s
+      | otherwise = (fmap . fmap) SetMasterNTall . handleMessage l $ mess
+
+  description (SetMasterNTall l) = description l

nix/configurations/vanadium/home/xmonad/xmonad.hs

@@ -16,7 +16,6 @@ import XMonad.Hooks.OnPropertyChange
 import XMonad.Hooks.RefocusLast
 import XMonad.Hooks.StatusBar
 import XMonad.Layout.FocusTracking
-import XMonad.Layout.IfMax
 import XMonad.Layout.Magnifier hiding (Toggle)
 import qualified XMonad.Layout.Magnifier as Mag
 import XMonad.Layout.NoBorders
@@ -24,6 +23,7 @@ import XMonad.Layout.Reflect
 import XMonad.Layout.Reflect.Message
 import XMonad.Layout.Renamed
 import XMonad.Layout.ResizableTile
+import XMonad.Layout.SetMasterNTall
 import XMonad.Layout.Spacing
 import XMonad.Layout.ToggleLayouts
 import qualified XMonad.StackSet as W
@@ -71,23 +71,16 @@ main =
 myLayout =
     avoidStruts
   $ smartBorders
-  $ toggleLayouts (mag tallr) full
+  $ toggleLayouts (magnifierOff tallr) full
   where
-    mag = magnifierOff
-
     full = focusTracking Full
 
-    mkTallrN n =
-      smartSpacingWithEdge 5
-      $ reflectMsg . reflectHoriz
-      $ ResizableTall n (1/10) (3/7) []
-
     tallr =
       renamed [ Replace "Tall" ]
-      $ ifMax 3 (mkTallrN 1)
-      $ ifMax 5 (mkTallrN 2)
-      $ ifMax 7 (mkTallrN 3)
-      $ mkTallrN 4
+      $ smartSpacingWithEdge 5
+      $ reflectMsg . reflectHoriz
+      $ SetMasterNTall
+      $ ResizableTall 1 (1/10) (3/7) []
 
 isSioyek :: Query Bool
 isSioyek = className =? "sioyek"
@@ -202,14 +195,33 @@ myEventHandleHook =
   -- Imagine Spotify playing in the background, a track change would focus that workspace.
   -- We prevent this by checking if the window is in the current workspace
   onTitleChange
-    $ (windowIsInCurrentWorkspace -->)
-    $ composeAll
+    ( windowIsInCurrentWorkspace --> composeAll
         [ isSpotify  --> doShiftAndGreedyView multimediaWS
         , isYouTube  --> doShiftAndGreedyView multimediaWS
         , isDiscord  --> doShiftAndGreedyView chatWS
         , isWhatsApp --> doShiftAndGreedyView chatWS
         , isElement  --> doShiftAndGreedyView chatWS
         ]
+    )
+  <> setMasterNEventHandleHook
+
+setMasterNEventHandleHook :: Event -> X All
+setMasterNEventHandleHook ev =
+  let adjustMasterCount :: X ()
+      adjustMasterCount = do
+          count <- gets $ length . W.integrate' . W.stack . W.workspace . W.current . windowset
+          if count <= 3 then sendMessage (SetMasterN 1)
+          else if count <= 5 then sendMessage (SetMasterN 2)
+          else if count <= 7 then sendMessage (SetMasterN 3)
+          else pure ()
+  in  do
+    case ev of
+      MapRequestEvent{} -> adjustMasterCount
+      ConfigureEvent{} -> adjustMasterCount
+      DestroyWindowEvent {} -> adjustMasterCount
+      _ -> pure ()
+
+    pure (All True)
 
 doShiftAndGreedyView :: WorkspaceId -> Query (Endo WindowSet)
 doShiftAndGreedyView n = doF . go =<< ask