{-# OPTIONS_GHC -fglasgow-exts #-} -- For deriving Data/Typeable
{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, PatternGuards, TypeSynonymInstances #-}
-- --------------------------------------------------------------------------
-- |
-- Module : Layouts.hs
-- Copyright : (c) Spencer Janssen 2007
-- License : BSD3-style (see LICENSE)
--
-- Maintainer : sjanssen@cse.unl.edu
-- Stability : unstable
-- Portability : not portable, Typeable deriving, mtl, posix
--
-- The collection of core layouts.
--
-----------------------------------------------------------------------------
module XMonad.Layout (ChangeLayout(..), Choose, (|||), Resize(..), IncMasterN(..),
Full(..), Tall(..), Mirror(..), mirrorRect, splitVertically,
splitHorizontally, splitHorizontallyBy, splitVerticallyBy) where
import XMonad.Core
import Graphics.X11 (Rectangle(..))
import qualified XMonad.StackSet as W
import Control.Arrow ((***), second)
import Control.Monad
import Data.Maybe (fromMaybe)
------------------------------------------------------------------------
-- LayoutClass selection manager
-- | A layout that allows users to switch between various layout options.
-- | Messages to change the current layout.
data ChangeLayout = FirstLayout | NextLayout deriving (Eq, Show, Typeable)
instance Message ChangeLayout
-- | The layout choice combinator
(|||) :: (LayoutClass l a, LayoutClass r a) => l a -> r a -> Choose l r a
(|||) = flip SLeft
infixr 5 |||
data Choose l r a = SLeft (r a) (l a)
| SRight (l a) (r a) deriving (Read, Show)
data NextNoWrap = NextNoWrap deriving (Eq, Show, Typeable)
instance Message NextNoWrap
-- This has lots of pseudo duplicated code, we must find a better way
instance (LayoutClass l a, LayoutClass r a) => LayoutClass (Choose l r) a where
doLayout (SLeft r l) = (fmap (second . fmap $ SLeft r) .) . doLayout l
doLayout (SRight l r) = (fmap (second . fmap $ SRight l) .) . doLayout r
description (SLeft _ l) = description l
description (SRight _ r) = description r
handleMessage lr m | Just FirstLayout <- fromMessage m = case lr of
SLeft {} -> return Nothing
SRight l r -> fmap (Just . flip SLeft l . fromMaybe r)
$ handleMessage r (SomeMessage Hide)
handleMessage lr m | Just NextLayout <- fromMessage m = do
mlr <- handleMessage lr $ SomeMessage NextNoWrap
maybe (handleMessage lr $ SomeMessage FirstLayout) (return . Just) mlr
handleMessage (SLeft r l) m | Just NextNoWrap <- fromMessage m = do
handleMessage l (SomeMessage Hide)
mr <- handleMessage r (SomeMessage FirstLayout)
return . Just . SRight l $ fromMaybe r mr
handleMessage lr m | Just ReleaseResources <- fromMessage m =
liftM2 ((Just .) . cons)
(fmap (fromMaybe l) $ handleMessage l m)
(fmap (fromMaybe r) $ handleMessage r m)
where (cons, l, r) = case lr of
(SLeft r' l') -> (flip SLeft, l', r')
(SRight l' r') -> (SRight, l', r')
-- The default cases for left and right:
handleMessage (SLeft r l) m = fmap (fmap $ SLeft r) $ handleMessage l m
handleMessage (SRight l r) m = fmap (fmap $ SRight l) $ handleMessage r m
--
-- | Builtin layout algorithms:
--
-- > fullscreen mode
-- > tall mode
--
-- The latter algorithms support the following operations:
--
-- > Shrink
-- > Expand
--
data Resize = Shrink | Expand deriving Typeable
-- | You can also increase the number of clients in the master pane
data IncMasterN = IncMasterN Int deriving Typeable
instance Message Resize
instance Message IncMasterN
-- | Simple fullscreen mode, just render all windows fullscreen.
data Full a = Full deriving (Show, Read)
instance LayoutClass Full a
-- | The inbuilt tiling mode of xmonad, and its operations.
data Tall a = Tall Int Rational Rational deriving (Show, Read)
instance LayoutClass Tall a where
pureLayout (Tall nmaster _ frac) r s = zip ws rs
where ws = W.integrate s
rs = tile frac r nmaster (length ws)
pureMessage (Tall nmaster delta frac) m = msum [fmap resize (fromMessage m)
,fmap incmastern (fromMessage m)]
where resize Shrink = Tall nmaster delta (max 0 $ frac-delta)
resize Expand = Tall nmaster delta (min 1 $ frac+delta)
incmastern (IncMasterN d) = Tall (max 0 (nmaster+d)) delta frac
description _ = "Tall"
-- | Mirror a rectangle
mirrorRect :: Rectangle -> Rectangle
mirrorRect (Rectangle rx ry rw rh) = (Rectangle ry rx rh rw)
-- | Mirror a layout, compute its 90 degree rotated form.
data Mirror l a = Mirror (l a) deriving (Show, Read)
instance LayoutClass l a => LayoutClass (Mirror l) a where
doLayout (Mirror l) r s = (map (second mirrorRect) *** fmap Mirror)
`fmap` doLayout l (mirrorRect r) s
handleMessage (Mirror l) = fmap (fmap Mirror) . handleMessage l
description (Mirror l) = "Mirror "++ description l
-- | tile. Compute the positions for windows using the default 2 pane tiling algorithm.
--
-- The screen is divided (currently) into two panes. all clients are
-- then partioned between these two panes. one pane, the `master', by
-- convention has the least number of windows in it (by default, 1).
-- the variable `nmaster' controls how many windows are rendered in the
-- master pane.
--
-- `delta' specifies the ratio of the screen to resize by.
--
-- 'frac' specifies what proportion of the screen to devote to the
-- master area.
--
tile :: Rational -> Rectangle -> Int -> Int -> [Rectangle]
tile f r nmaster n = if n <= nmaster || nmaster == 0
then splitVertically n r
else splitVertically nmaster r1 ++ splitVertically (n-nmaster) r2 -- two columns
where (r1,r2) = splitHorizontallyBy f r
--
-- Divide the screen vertically into n subrectangles
--
splitVertically, splitHorizontally :: Int -> Rectangle -> [Rectangle]
splitVertically n r | n < 2 = [r]
splitVertically n (Rectangle sx sy sw sh) = Rectangle sx sy sw smallh :
splitVertically (n-1) (Rectangle sx (sy+fromIntegral smallh) sw (sh-smallh))
where smallh = sh `div` fromIntegral n --hmm, this is a fold or map.
splitHorizontally n = map mirrorRect . splitVertically n . mirrorRect
-- Divide the screen into two rectangles, using a rational to specify the ratio
splitHorizontallyBy, splitVerticallyBy :: RealFrac r => r -> Rectangle -> (Rectangle, Rectangle)
splitHorizontallyBy f (Rectangle sx sy sw sh) =
( Rectangle sx sy leftw sh
, Rectangle (sx + fromIntegral leftw) sy (sw-fromIntegral leftw) sh)
where leftw = floor $ fromIntegral sw * f
splitVerticallyBy f = (mirrorRect *** mirrorRect) . splitHorizontallyBy f . mirrorRect
