add Mosaic layout.

Mosaic.hs

@@ -0,0 +1,183 @@
+module XMonadContrib.Mosaic ( mosaic, expandWindow, shrinkWindow, squareWindow ) where
+
+-- This module defines a "mosaic" layout, which tries to give all windows
+-- equal area, while also trying to give them a user-defined (and run-time
+-- adjustable) aspect ratio.  You can use mod-l and mod-h to adjust the
+-- aspect ratio (which probably won't have a very interesting effect unless
+-- you've got a number of windows upen.
+
+-- My intent is to extend this layout to optimize various constraints, such
+-- as windows that should have a different aspect ratio, a fixed size, or
+-- minimum dimensions in certain directions.
+
+-- You can use this module with the following in your config file:
+
+-- import XMonad.Mosaic
+-- import Control.Monad.State ( gets )
+-- import qualified StackSet as W ( peek )
+
+-- defaultLayouts :: [Layout LayoutMsg]
+-- defaultLayouts = [ mosaic (1%4) (1%2) M.empty M.empty, full,
+--                    tall defaultDelta (1%2), wide defaultDelta (1%2) ]
+
+-- In the key-bindings, do something like:
+
+--     , ((modMask .|. shiftMask, xK_h     ), do ws <- gets workspace
+--                                               whenJust (W.peek ws) $ \w ->
+--                                                   layoutMsg (shrinkWindow w))
+--     , ((modMask .|. shiftMask, xK_l     ), do ws <- gets workspace
+--                                               whenJust (W.peek ws) $ \w ->
+--                                                   layoutMsg (expandWindow w))
+--     , ((modMask .|. shiftMask, xK_s     ), do ws <- gets workspace
+--                                               whenJust (W.peek ws) $ \w ->
+--                                                   layoutMsg (squareWindow w))
+
+import Data.Ratio
+import Graphics.X11.Xlib
+import XMonad
+import Operations ( ShrinkOrExpand (Shrink, Expand) )
+import qualified Data.Map as M
+import Data.List ( sort )
+import Data.Dynamic ( Typeable, fromDynamic )
+import Control.Monad ( mplus )
+
+import System.IO.Unsafe
+
+data HandleWindow = ExpandWindow Window | ShrinkWindow Window | SquareWindow Window
+                    deriving ( Typeable, Eq )
+expandWindow, shrinkWindow, squareWindow :: Window -> HandleWindow
+expandWindow = ExpandWindow
+shrinkWindow = ShrinkWindow
+squareWindow = SquareWindow
+
+mosaic :: Rational -> Rational -> M.Map Window WindowRater -> M.Map Window Area -> Layout
+mosaic delta tileFrac raters areas = Layout { doLayout = mosaicL tileFrac raters areas
+                                            , modifyLayout = mlayout }
+    where mlayout x = (m1 `fmap` fromDynamic x) `mplus` (m2 `fmap` fromDynamic x)
+          m1 Shrink = mosaic delta (tileFrac/(1+delta)) raters areas
+          m1 Expand = mosaic delta (tileFrac*(1+delta)) raters areas
+          m2 (ExpandWindow w) = mosaic delta tileFrac raters
+                                -- (add_rater (\_ (Rectangle _ _ wid h) -> delta*(1-wid///h)) w raters)
+                                (multiply_area (1+delta) w areas)
+          m2 (ShrinkWindow w) = mosaic delta tileFrac raters
+                                -- (add_rater (\_ (Rectangle _ _ wid h) -> delta*(wid///h-1)) w raters)
+                                (multiply_area (1/(1+ delta)) w areas)
+          m2 (SquareWindow w) = mosaic delta tileFrac (M.insert w force_square raters) areas
+          force_square _ (Rectangle _ _ a b) = 100*(sqr(a///b) + sqr(b///a))
+          sqr a = a * a
+
+mytrace :: String -> a -> a
+mytrace s a = seq foo a
+    where foo = unsafePerformIO $ appendFile "/tmp/xmonad.trace" (s++"\n")
+
+myerror :: String -> a
+myerror s = seq foo $ error s
+    where foo = unsafePerformIO $ appendFile "/tmp/xmonad.trace" (s++"\n")
+
+multiply_area :: Area -> Window -> M.Map Window Area -> M.Map Window Area
+multiply_area a w = M.alter (Just . f) w where f Nothing = a
+                                               f (Just a') = a'*a
+
+add_rater :: WindowRater -> Window -> M.Map Window WindowRater -> M.Map Window WindowRater
+add_rater r w = M.alter f w where f Nothing= Just r
+                                  f (Just r') = Just $ \foo bar -> r foo bar + r' foo bar
+
+type WindowRater = Window -> Rectangle -> Rational
+
+mosaicL :: Rational -> M.Map Window WindowRater -> M.Map Window Area
+        -> Rectangle -> [Window] -> [(Window, Rectangle)]
+mosaicL _ _ _ _ [] = []
+mosaicL f raters areas origRect origws
+    = flattenMosaic $ the_value $ if myv < myh then myv else myh
+    where mean_area = area origRect / fromIntegral (length origws)
+          myv = my_mosaic origRect Vertical sortedws
+          myh = my_mosaic origRect Horizontal sortedws
+          sortedws = reverse $ map the_value $ sort $ map (\w -> Rated (sumareas [w]) w) origws
+
+          my_mosaic :: Rectangle -> CutDirection -> [Window]
+                    -> Rated Rational (Mosaic (Window, Rectangle))
+          my_mosaic _ _ [] = Rated 0 $ M []
+          my_mosaic r _ [w] = Rated (rating w r) $ OM (w,r)
+          my_mosaic r d ws = minL $
+                             map (fmap M . catRated .
+                                  map (\(ws',r') -> my_mosaic r' (otherDirection d) ws')) $
+                             map (\ws' -> zip ws' $ partitionR d r $ map sumareas ws') $
+                             init $ allsplits ws
+              where minL [] = myerror "minL on empty list"
+                    minL [a] = a
+                    minL (a:b:c) = minL (min a b:c)
+
+          partitionR :: CutDirection -> Rectangle -> [Area] -> [Rectangle]
+          partitionR _ _ [] = []
+          partitionR _ r [_] = [r]
+          partitionR d r (a:ars) = r1 : partitionR d r2 ars
+              where totarea = sum (a:ars)
+                    (r1,r2) = split d (a/totarea) r
+
+          rating :: WindowRater
+          rating w r = (M.findWithDefault default_preferences w raters) w r
+          default_preferences :: WindowRater
+          default_preferences _ r@(Rectangle _ _ w h)
+              | fr <- w /// h = sqr(fr/f)+sqr(f/fr)-2+ toRational (mean_area/area r)
+          sqr a = a * a
+          sumareas ws = sum $ map (\w -> M.findWithDefault 1 w areas) ws
+
+
+
+catRated :: Num v => [Rated v a] -> Rated v [a]
+catRated xs = Rated (sum $ map the_rating xs) (map the_value xs)
+
+data Rated a b = Rated !a !b
+instance Functor (Rated a) where
+    f `fmap` (Rated v a) = Rated v (f a)
+
+the_value :: Rated a b -> b
+the_value (Rated _ b) = b
+the_rating :: Rated a b -> a
+the_rating (Rated a _) = a
+
+instance Eq a => Eq (Rated a b) where
+    (Rated a _) == (Rated a' _) = a == a'
+instance Ord a => Ord (Rated a b) where
+    compare (Rated a _) (Rated a' _) = compare a a'
+
+type Area = Rational
+
+area :: Rectangle -> Area
+area (Rectangle _ _ w h) = fromIntegral w * fromIntegral h
+
+(///) :: (Integral a, Integral b) => a -> b -> Rational
+a /// b = fromIntegral a / fromIntegral b
+
+
+split :: CutDirection -> Rational -> Rectangle -> (Rectangle, Rectangle)
+split Vertical frac (Rectangle sx sy sw sh) = (Rectangle sx sy sw h,
+                                               Rectangle sx (sy+fromIntegral h) sw (sh-h))
+    where h = floor $ fromIntegral sh * frac
+split Horizontal frac (Rectangle sx sy sw sh) = (Rectangle sx sy w sh,
+                                                 Rectangle (sx+fromIntegral w) sy (sw-w) sh)
+    where w = floor $ fromIntegral sw * frac
+
+data CutDirection = Vertical | Horizontal
+otherDirection :: CutDirection -> CutDirection
+otherDirection Vertical = Horizontal
+otherDirection Horizontal = Vertical
+
+data Mosaic a where
+    M :: [Mosaic a] -> Mosaic a
+    OM :: a -> Mosaic a
+
+flattenMosaic :: Mosaic a -> [a]
+flattenMosaic (OM a) = [a]
+flattenMosaic (M xs) = concatMap flattenMosaic xs
+
+allsplits :: [a] -> [[[a]]]
+allsplits [] = [[[]]]
+allsplits [a] = [[[a]]]
+allsplits (x:xs) = (map ([x]:) splitsrest) ++
+                   (map (maphead (x:)) splitsrest)
+    where splitsrest = allsplits xs
+
+maphead :: (a->a) -> [a] -> [a]
+maphead f (x:xs) = f x : xs
+maphead _ [] = []