MosaicAlt take 2

MosaicAlt.hs

@@ -21,6 +21,8 @@ module XMonadContrib.MosaicAlt (
         MosaicAlt(..)
         , shrinkWindowAlt
         , expandWindowAlt
+        , tallWindowAlt
+        , wideWindowAlt
         , resetAlt
     ) where
 
@@ -45,6 +47,8 @@ import Graphics.X11.Types ( Window )
 -- > keys = ...
 -- >     , ((modMask .|. shiftMask, xK_a), withFocused (sendMessage . expandWindowAlt))
 -- >     , ((modMask .|. shiftMask, xK_z), withFocused (sendMessage . shrinkWindowAlt))
+-- >     , ((modMask .|. shiftMask, xK_s), withFocused (sendMessage . tallWindowAlt))
+-- >     , ((modMask .|. shiftMask, xK_d), withFocused (sendMessage . wideWindowAlt))
 -- >     , ((modMask .|. controlMask, xK_space), sendMessage resetAlt)
 -- >     ...
 
@@ -54,83 +58,104 @@ import Graphics.X11.Types ( Window )
 data HandleWindowAlt =
     ShrinkWindowAlt Window
     | ExpandWindowAlt Window
+    | TallWindowAlt Window
+    | WideWindowAlt Window
     | ResetAlt
     deriving ( Typeable, Eq )
 instance Message HandleWindowAlt
 shrinkWindowAlt, expandWindowAlt :: Window -> HandleWindowAlt
+tallWindowAlt, wideWindowAlt :: Window -> HandleWindowAlt
 shrinkWindowAlt = ShrinkWindowAlt
 expandWindowAlt = ExpandWindowAlt
+tallWindowAlt = TallWindowAlt
+wideWindowAlt = WideWindowAlt
 resetAlt :: HandleWindowAlt
 resetAlt = ResetAlt
 
-type Areas = M.Map Window Rational
+data Param = Param { area, aspect :: Rational } deriving ( Show, Read )
-data MosaicAlt a = MosaicAlt Areas deriving ( Show, Read )
+type Params = M.Map Window Param
+data MosaicAlt a = MosaicAlt Params deriving ( Show, Read )
 
 instance LayoutClass MosaicAlt Window where
     description _ = "MosaicAlt"
-    doLayout (MosaicAlt areas) rect stack =
+    doLayout (MosaicAlt params) rect stack =
-            return (arrange rect stack areas', Just $ MosaicAlt areas')
+            return (arrange rect stack params', Just $ MosaicAlt params')
         where
-            areas' = ins (W.up stack) $ ins (W.down stack) $ ins [W.focus stack] areas
+            params' = ins (W.up stack) $ ins (W.down stack) $ ins [W.focus stack] params
-            ins wins as = foldl M.union as $ map (`M.singleton` 1) wins
+            ins wins as = foldl M.union as $ map (`M.singleton` (Param 1 1.5)) wins
 
-    handleMessage (MosaicAlt areas) msg = return $ case fromMessage msg of
+    handleMessage (MosaicAlt params) msg = return $ case fromMessage msg of
-        Just (ShrinkWindowAlt w) -> Just $ MosaicAlt $ alter areas w (4 % 5)
+        Just (ShrinkWindowAlt w) -> Just $ MosaicAlt $ alter params w (4 % 5) 1
-        Just (ExpandWindowAlt w) -> Just $ MosaicAlt $ alter areas w (6 % 5)
+        Just (ExpandWindowAlt w) -> Just $ MosaicAlt $ alter params w (6 % 5) 1
+        Just (TallWindowAlt w) -> Just $ MosaicAlt $ alter params w 1 (3 % 4)
+        Just (WideWindowAlt w) -> Just $ MosaicAlt $ alter params w 1 (5 % 4)
         Just ResetAlt -> Just $ MosaicAlt M.empty
         _ -> Nothing
 
--- Layout algorithm entry point.
+-- Change requested params for a window.
-arrange :: Rectangle -> W.Stack Window -> Areas -> [(Window, Rectangle)]
+alter :: Params -> Window -> Rational -> Rational -> Params
-arrange rect stack areas = tree rect (sortBy areaCompare winList) totalArea areas
+alter params win arDelta asDelta = case M.lookup win params of
-    where
+    Just (Param ar as) -> M.insert win (Param (ar * arDelta) (as * asDelta)) params
-        winList = reverse (W.up stack) ++ W.focus stack : W.down stack
+    Nothing -> M.insert win (Param arDelta (1.5 * asDelta)) params
-        totalArea = areaSum areas winList
-        areaCompare a b = or1 b `compare` or1 a
-        or1 w = maybe 1 id $ M.lookup w areas
 
--- Selects a horizontal or vertical split to get the best aspect ratio.
+-- Layout algorithm entry point.
--- FIXME: Give the user more dynamic control.
+arrange :: Rectangle -> W.Stack Window -> Params -> [(Window, Rectangle)]
-splitBest :: Rational -> Rectangle -> (Rectangle, Rectangle)
+arrange rect stack params = r
-splitBest ratio rect =
-        if (w % h) < cutoff then splitVerticallyBy ratio rect
-            else splitHorizontallyBy ratio rect
     where
-        -- Prefer wide windows to tall ones, mainly because it makes xterms more usable.
+        (_, r) = findSplits 3 rect tree params
-        cutoff = if w > 1000 then 1.25
+        tree = makeTree (sortBy areaCompare wins) params
-            else if w < 500 then 2.25
+        wins = reverse (W.up stack) ++ W.focus stack : W.down stack
-            else 2.25 - (w - 500) % 500
+        areaCompare a b = or1 b `compare` or1 a
-        w = rect_width rect
+        or1 w = maybe 1 area $ M.lookup w params
-        h = rect_height rect
 
 -- Recursively group windows into a binary tree. Aim to balance the tree
 -- according to the total requested area in each branch.
-tree :: Rectangle -> [Window] -> Rational -> Areas -> [(Window, Rectangle)]
+data Tree = Node (Rational, Tree) (Rational, Tree) | Leaf Window | None
-tree rect winList totalArea areas = case winList of
+makeTree :: [Window] -> Params -> Tree
-    [] -> []
+makeTree wins params = case wins of
-    [x] -> [(x, rect)]
+    [] -> None
-    _ -> tree aRect aWins aArea areas ++ tree bRect bWins bArea areas
+    [x] -> Leaf x
-        where
+    _ -> Node (aArea, makeTree aWins params) (bArea, makeTree bWins params)
-            (aRect, bRect) = splitBest (aArea / (aArea + bArea)) rect
+        where ((aWins, aArea), (bWins, bArea)) = areaSplit params wins
-            ((aWins, aArea), (bWins, bArea)) = areaSplit areas winList totalArea
-
--- Sum the requested areas of a bunch of windows.
-areaSum :: Areas -> [Window] -> Rational
-areaSum areas = sum . map (maybe 1 id . flip M.lookup areas)
 
 -- Split a list of windows in half by area.
-areaSplit :: Areas -> [Window] -> Rational -> (([Window], Rational), ([Window], Rational))
+areaSplit :: Params -> [Window] -> (([Window], Rational), ([Window], Rational))
-areaSplit areas wins totalArea = ((reverse aWins, aArea), (bWins, bArea))
+areaSplit params wins = gather [] 0 [] 0 wins
     where
-        ((aWins, aArea), (bWins, bArea)) = gather [] wins 0
+        gather a aa b ba (r : rs) =
-        gather a b t = if t >= (totalArea / 2) then ((a, t), (b, totalArea - t))
+            if aa <= ba
-            else gather (head b : a) (tail b) (t + or1 (head b))
+                then gather (r : a) (aa + or1 r) b ba rs
-        or1 w = maybe 1 id $ M.lookup w areas
+                else gather a aa (r : b) (ba + or1 r) rs
+        gather a aa b ba [] = ((reverse a, aa), (b, ba))
+        or1 w = maybe 1 area $ M.lookup w params
 
--- Change requested area for a window.
+-- Figure out which ways to split the space, by exhaustive search.
-alter :: Areas -> Window -> Rational -> Areas
+-- Complexity is quadratic in the number of windows.
-alter areas win delta = case M.lookup win areas of
+findSplits :: Int -> Rectangle -> Tree -> Params -> (Double, [(Window, Rectangle)])
-    Just v -> M.insert win (v * delta) areas
+findSplits _ _ None _ = (0, [])
-    Nothing -> M.insert win delta areas
+findSplits _ rect (Leaf w) params = (aspectBadness rect w params, [(w, rect)])
+findSplits depth rect (Node (aArea, aTree) (bArea, bTree)) params =
+        if hBadness < vBadness then (hBadness, hList) else (vBadness, vList)
+    where
+        (hBadness, hList) = trySplit splitHorizontallyBy
+        (vBadness, vList) = trySplit splitVerticallyBy
+        trySplit splitBy =
+                (aBadness + bBadness, aList ++ bList)
+            where
+                (aBadness, aList) = findSplits (depth - 1) aRect aTree params
+                (bBadness, bList) = findSplits (depth - 1) bRect bTree params
+                (aRect, bRect) = splitBy ratio rect
+        ratio = aArea / (aArea + bArea)
+
+-- Decide how much we like this rectangle.
+aspectBadness :: Rectangle -> Window -> Params -> Double
+aspectBadness rect win params =
+        (if a < 1 then tall else wide) * sqrt(w * h)
+    where
+        tall = if w < 700 then ((1 / a) * (700 / w)) else 1 / a
+        wide = if w < 700 then a else (a * w / 700)
+        a = (w / h) / fromRational (maybe 1.5 aspect $ M.lookup win params)
+        w = fromIntegral $ rect_width rect
+        h = fromIntegral $ rect_height rect
 
 -- vim: sw=4:et