first shot at a floating layer

This is a first attempting at a floating layer:

mod-button1: move window
mod-button2: swapMaster
mod-button3: resize window

mod-t: make floating window tiled again

Moving or resizing a window automatically makes it floating.

Known issues:

Hard to manage stacking order. You can promote a window to move it to the top,
(which you can do with mod-button2) but it should be easier than that.

Moving a window by dragging it to a different Xinerama screen does not move it
to that workspace.

Code is ugly.

Config.hs

@@ -115,6 +115,8 @@ keys = M.fromList $
     , ((modMask,               xK_h     ), sendMessage Shrink) -- @@ Shrink the master area
     , ((modMask,               xK_l     ), sendMessage Expand) -- @@ Expand the master area
 
+    , ((modMask,               xK_t     ), withFocused clearFloating) -- @@ Make floating window tiled
+
     -- increase or decrease number of windows in the master area
     , ((modMask              , xK_comma ), sendMessage (IncMasterN 1)) -- @@ Increment the number of windows in the master area
     , ((modMask              , xK_period), sendMessage (IncMasterN (-1))) -- @@ Deincrement the number of windows in the master area

Config.hs-boot

@@ -1,3 +1,5 @@
 module Config where
 import Graphics.X11.Xlib.Types (Dimension)
+import Graphics.X11.Xlib (KeyMask)
 borderWidth :: Dimension
+modMask     :: KeyMask

Main.hs

@@ -26,7 +26,7 @@ import Graphics.X11.Xinerama    (getScreenInfo)
 import XMonad
 import Config
 import StackSet (new)
-import Operations   (manage, unmanage, focus, setFocusX, full, isClient, rescreen)
+import Operations   (manage, unmanage, focus, setFocusX, full, isClient, rescreen, makeFloating, swapMaster)
 
 --
 -- The main entry point
@@ -111,6 +111,41 @@ grabKeys dpy rootw = do
 
   where grab kc m = grabKey dpy kc m rootw True grabModeAsync grabModeAsync
 
+cleanMask :: KeyMask -> KeyMask
+cleanMask = (complement (numlockMask .|. lockMask) .&.)
+
+mouseDrag :: (XMotionEvent -> IO ()) -> X ()
+mouseDrag f = do
+    XConf { theRoot = root, display = d } <- ask
+    io $ grabPointer d root False (buttonReleaseMask .|. pointerMotionMask) grabModeAsync grabModeAsync none none currentTime
+
+    io $ allocaXEvent $ \p -> fix $ \again -> do
+        maskEvent d (buttonReleaseMask .|. pointerMotionMask) p
+        et <- get_EventType p
+        when (et == motionNotify) $ get_MotionEvent p >>= f >> again
+
+    io $ ungrabPointer d currentTime
+
+mouseMoveWindow :: Window -> X ()
+mouseMoveWindow w = withDisplay $ \d -> do
+    io $ raiseWindow d w
+    wa <- io $ getWindowAttributes d w
+    (_, _, _, ox, oy, _, _, _) <- io $ queryPointer d w
+    mouseDrag $ \(_, _, _, ex, ey, _, _, _, _, _) ->
+        moveWindow d w (fromIntegral (fromIntegral (wa_x wa) + (ex - ox))) (fromIntegral (fromIntegral (wa_y wa) + (ey - oy)))
+
+    makeFloating w
+
+mouseResizeWindow :: Window -> X ()
+mouseResizeWindow w = withDisplay $ \d -> do
+    io $ raiseWindow d w
+    wa <- io $ getWindowAttributes d w
+    io $ warpPointer d none w 0 0 0 0 (fromIntegral (wa_width wa)) (fromIntegral (wa_height wa))
+    mouseDrag $ \(_, _, _, ex, ey, _, _, _, _, _) ->
+        resizeWindow d w (fromIntegral (max 1 (ex - fromIntegral (wa_x wa)))) (fromIntegral (max 1 (ey - fromIntegral (wa_y wa))))
+
+    makeFloating w
+
 -- ---------------------------------------------------------------------
 -- | Event handler. Map X events onto calls into Operations.hs, which
 -- modify our internal model of the window manager state.
@@ -128,7 +163,7 @@ handle :: Event -> X ()
 handle (KeyEvent {ev_event_type = t, ev_state = m, ev_keycode = code})
     | t == keyPress = withDisplay $ \dpy -> do
         s  <- io $ keycodeToKeysym dpy code 0
-        whenJust (M.lookup (complement (numlockMask .|. lockMask) .&. m,s) keys) id
+        whenJust (M.lookup (cleanMask m,s) keys) id
 
 -- manage a new window
 handle (MapRequestEvent    {ev_window = w}) = withDisplay $ \dpy -> do
@@ -146,7 +181,11 @@ handle e@(MappingNotifyEvent {ev_window = w}) = do
     when (ev_request e == mappingKeyboard) $ withDisplay $ io . flip grabKeys w
 
 -- click on an unfocused window, makes it focused on this workspace
-handle (ButtonEvent {ev_window = w, ev_event_type = t}) | t == buttonPress = focus w
+handle (ButtonEvent {ev_window = w, ev_event_type = t, ev_state = m, ev_button = b })
+    | t == buttonPress && cleanMask m == modMask && b == button1 = mouseMoveWindow w
+    | t == buttonPress && cleanMask m == modMask && b == button2 = focus w >> swapMaster
+    | t == buttonPress && cleanMask m == modMask && b == button3 = mouseResizeWindow w
+    | t == buttonPress = focus w
 
 -- entered a normal window, makes this focused.
 handle e@(CrossingEvent {ev_window = w, ev_event_type = t})

Operations.hs

@@ -15,11 +15,12 @@ module Operations where
 
 import XMonad
 import qualified StackSet as W
-import {-# SOURCE #-} Config (borderWidth)
+import {-# SOURCE #-} Config (borderWidth, modMask)
 
 import Data.Maybe
-import Data.List            (genericIndex, intersectBy)
+import Data.List            (genericIndex, intersectBy, partition, delete)
 import Data.Bits            ((.|.))
+import Data.Ratio
 import qualified Data.Map as M
 
 -- import System.Mem (performGC)
@@ -38,17 +39,29 @@ import Graphics.X11.Xlib.Extras
 -- Bring it into focus. If the window is already managed, nothing happens.
 --
 manage :: Window -> X ()
-manage w = do
-    withDisplay $ \d -> io $ do
-        selectInput d w $ structureNotifyMask .|. enterWindowMask .|. propertyChangeMask
-        mapWindow d w
-        setWindowBorderWidth d w borderWidth
-    windows $ W.insertUp w
+manage w = withDisplay $ \d -> do
+    io $ selectInput d w $ structureNotifyMask .|. enterWindowMask .|. propertyChangeMask
+    io $ mapWindow d w
+    io $ setWindowBorderWidth d w borderWidth
+
+    -- FIXME: This is pretty awkward. We can't can't let "refresh" happen
+    -- before the call to makeFloating, because that will resize the window and
+    -- lose the default sizing.
+    isTransient <- isJust `liftM` (io $ getTransientForHint d w)
+    if isTransient
+        then do
+            modify $ \s -> s { windowset = W.insertUp w (windowset s) }
+            makeFloating w
+        else windows $ W.insertUp w
 
 -- | unmanage. A window no longer exists, remove it from the window
 -- list, on whatever workspace it is.
+--
+-- FIXME: clearFloating should be taken care of in W.delete, but if we do it
+-- there, floating status is lost when moving windows between workspaces,
+-- because W.shift calls W.delete.
 unmanage :: Window -> X ()
-unmanage = windows . W.delete
+unmanage w = windows $ W.clearFloating w . W.delete w
 
 -- | focus. focus window up or down. or swap various windows.
 focusUp, focusDown, swapUp, swapDown, swapMaster :: X ()
@@ -141,6 +154,7 @@ refresh = do
         let n      = W.tag (W.workspace w)
             this   = W.view n ws
             Just l = fmap fst $ M.lookup n fls
+            (float, tiled) = partition (flip M.member (W.floating ws)) (W.index this)
             (Rectangle sx sy sw sh) = genericIndex xinesc (W.screen w)
             (gt,gb,gl,gr)           = genericIndex gaps   (W.screen w)
 
@@ -148,11 +162,19 @@ refresh = do
         rs <- doLayout l (Rectangle (sx + fromIntegral gl)
                                     (sy + fromIntegral gt)
                                     (sw - fromIntegral (gl + gr))
-                                    (sh - fromIntegral (gt + gb))) (W.index this)
+                                    (sh - fromIntegral (gt + gb))) tiled
         mapM_ (\(win,rect) -> io (tileWindow d win rect)) rs
 
-        -- and raise the focused window if there is one.
-        whenJust (W.peek this) $ io . raiseWindow d
+        -- move/resize the floating windows
+        (`mapM_` float) $ \fw -> whenJust (M.lookup fw (W.floating ws)) $ \(W.RationalRect rx ry rw rh) -> do
+            let Rectangle px py pw ph = genericIndex xinesc (W.screen w)
+            io $ tileWindow d fw (Rectangle (px + floor (toRational pw*rx)) (py + floor (toRational ph*ry)) (floor (toRational pw*rw)) (floor (toRational ph*rh)))
+
+        -- urgh. This is required because the fullscreen layout assumes that
+        -- the focused window will be raised.
+        let tiled' = maybe tiled (\x -> if x `elem` tiled then x : delete x tiled else tiled) (W.peek this)
+
+        io $ restackWindows d (float ++ tiled')
 
     setTopFocus
     clearEnterEvents
@@ -198,15 +220,13 @@ rescreen = do
 
 -- ---------------------------------------------------------------------
 
-buttonsToGrab :: [Button]
-buttonsToGrab = [button1, button2, button3]
-
 -- | setButtonGrab. Tell whether or not to intercept clicks on a given window
 setButtonGrab :: Bool -> Window -> X ()
-setButtonGrab grab w = withDisplay $ \d -> io $ (`mapM_` buttonsToGrab) $ \b ->
-    if grab then grabButton d b anyModifier w False (buttonPressMask .|. buttonReleaseMask)
-                   grabModeAsync grabModeSync none none
-            else ungrabButton d b anyModifier w
+setButtonGrab grab w = withDisplay $ \d -> io $ do
+    when (not grab) $ ungrabButton d anyButton anyModifier w
+    grabButton d anyButton mask w False (buttonPressMask .|. buttonReleaseMask)
+               grabModeAsync grabModeSync none none
+    where mask = if grab then anyModifier else modMask
 
 -- ---------------------------------------------------------------------
 -- Setting keyboard focus
@@ -239,10 +259,11 @@ setFocusX w = withWorkspace $ \ws -> do
             setButtonGrab True otherw
             io $ setWindowBorder dpy otherw (color_pixel nbc)
 
-    io $ do setInputFocus dpy w revertToPointerRoot 0
-            -- raiseWindow dpy w
-    setButtonGrab False w
-    io $ setWindowBorder dpy w (color_pixel fbc)
+    whenX (not `liftM` isRoot w) $ do
+        io $ do setInputFocus dpy w revertToPointerRoot 0
+                -- raiseWindow dpy w
+        setButtonGrab False w
+        io $ setWindowBorder dpy w (color_pixel fbc)
 
 -- ---------------------------------------------------------------------
 -- Managing layout
@@ -360,3 +381,21 @@ withFocused f = withWorkspace $ \w -> whenJust (W.peek w) f
 -- | True if window is under management by us
 isClient :: Window -> X Bool
 isClient w = withWorkspace $ return . W.member w
+
+-- | Make a floating window tiled
+clearFloating :: Window -> X ()
+clearFloating = windows . W.clearFloating
+
+-- | Make a tiled window floating
+makeFloating :: Window -> X ()
+makeFloating w = withDisplay $ \d -> do
+    xinesc <- gets xineScreens
+    sc     <- (genericIndex xinesc . W.screen . W.current) `liftM` gets windowset
+    wa     <- io $ getWindowAttributes d w
+    let bw = fI . wa_border_width $ wa
+    windows $ W.makeFloating w
+        (W.RationalRect ((fI (wa_x wa) - fI (rect_x sc)) % fI (rect_width sc))
+                        ((fI (wa_y wa) - fI (rect_y sc)) % fI (rect_height sc))
+                        (fI (wa_width  wa + bw*2) % fI (rect_width sc))
+                        (fI (wa_height wa + bw*2) % fI (rect_height sc)))
+  where fI x = fromIntegral x

StackSet.hs

@@ -75,15 +75,15 @@
 -- 'delete'.
 --
 module StackSet (
-        StackSet(..), Workspace(..), Screen(..), Stack(..),
+        StackSet(..), Workspace(..), Screen(..), Stack(..), RationalRect(..),
         new, view, lookupWorkspace, peek, index, focusUp, focusDown,
         focusWindow, member, findIndex, insertUp, delete, shift,
-        swapMaster, swapUp, swapDown, modify -- needed by users
+        swapMaster, swapUp, swapDown, modify, makeFloating, clearFloating -- needed by users
     ) where
 
 import Data.Maybe   (listToMaybe)
 import qualified Data.List as L (delete,find,genericSplitAt)
-
+import qualified Data.Map  as M (Map,insert,delete,empty)
 
 -- API changes from xmonad 0.1:
 --  StackSet constructor arguments changed. StackSet workspace window screen
@@ -112,10 +112,11 @@ import qualified Data.List as L (delete,find,genericSplitAt)
 -- Xinerama screens, and those workspaces not visible anywhere.
 --
 data StackSet i a sid =
-    StackSet { size    :: !i                -- number of workspaces
-             , current :: !(Screen i a sid) -- currently focused workspace
-             , visible :: [Screen i a sid]  -- non-focused workspaces, visible in xinerama
-             , hidden  :: [Workspace i a]   -- workspaces not visible anywhere
+    StackSet { size     :: !i                   -- number of workspaces
+             , current  :: !(Screen i a sid)    -- currently focused workspace
+             , visible  :: [Screen i a sid]     -- non-focused workspaces, visible in xinerama
+             , hidden   :: [Workspace i a]      -- workspaces not visible anywhere
+             , floating :: M.Map a RationalRect -- floating windows
              } deriving (Show, Read, Eq)
 
 -- Visible workspaces, and their Xinerama screens.
@@ -128,6 +129,9 @@ data Screen i a sid = Screen { workspace :: !(Workspace i a), screen :: !sid }
 data Workspace i a = Workspace  { tag :: !i, stack :: Stack a }
     deriving (Show, Read, Eq)
 
+data RationalRect = RationalRect Rational Rational Rational Rational
+    deriving (Show, Read, Eq)
+
 -- 
 -- A stack is a cursor onto a (possibly empty) window list.
 -- The data structure tracks focus by construction, and
@@ -167,7 +171,7 @@ abort x = error $ "xmonad: StackSet: " ++ x
 -- Xinerama: Virtual workspaces are assigned to physical screens, starting at 0.
 --
 new :: (Integral i, Integral s) => i -> s -> StackSet i a s
-new n m | n > 0 && m > 0 = StackSet n cur visi unseen
+new n m | n > 0 && m > 0 = StackSet n cur visi unseen M.empty
         | otherwise      = abort "non-positive arguments to StackSet.new"
 
   where (seen,unseen) = L.genericSplitAt m $ Workspace 0 Empty : [ Workspace i Empty | i <- [1 ..n-1]]
@@ -351,7 +355,7 @@ insertUp a s = if member a s then s else insert
 --   * deleting the master window resets it to the newly focused window
 --   * otherwise, delete doesn't affect the master.
 --
-delete :: (Integral i, Eq a, Eq s) => a -> StackSet i a s -> StackSet i a s
+delete :: (Integral i, Ord a, Eq s) => a -> StackSet i a s -> StackSet i a s
 delete w s | Just w == peek s = remove s -- common case. 
            | otherwise = maybe s (removeWindow.tag.workspace.current $ s) (findIndex w s)
   where
@@ -367,6 +371,12 @@ delete w s | Just w == peek s = remove s -- common case.
         Node _ []     []     -> Empty
       else c { up = w `L.delete` up c, down = w `L.delete` down c }
 
+makeFloating :: Ord a => a -> RationalRect -> StackSet i a s -> StackSet i a s
+makeFloating w r s = s { floating = M.insert w r (floating s) }
+
+clearFloating :: Ord a => a -> StackSet i a s -> StackSet i a s
+clearFloating w s = s { floating = M.delete w (floating s) }
+
 ------------------------------------------------------------------------
 -- Setting the master window
 
@@ -390,7 +400,7 @@ swapMaster = modify Empty $ \c -> case c of
 -- The actual focused workspace doesn't change. If there is -- no
 -- element on the current stack, the original stackSet is returned.
 --
-shift :: (Eq a, Eq s, Integral i) => i -> StackSet i a s -> StackSet i a s
+shift :: (Ord a, Eq s, Integral i) => i -> StackSet i a s -> StackSet i a s
 shift n s = if and [n >= 0,n < size s,n /= tag (workspace (current s))]
             then maybe s go (peek s) else s
     where go w = foldr ($) s [view (tag (workspace (current s))),insertUp w,view n,delete w]