{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, PatternGuards, TypeSynonymInstances, DeriveDataTypeable #-}
-- --------------------------------------------------------------------------
-- |
-- Module : XMonad.Layout
-- Copyright : (c) Spencer Janssen 2007
-- License : BSD3-style (see LICENSE)
--
-- Maintainer : spencerjanssen@gmail.com
-- Stability : unstable
-- Portability : not portable, Typeable deriving, mtl, posix
--
-- The collection of core layouts.
--
-----------------------------------------------------------------------------
module XMonad.Layout (
Full(..), Tall(..), Mirror(..),
Resize(..), IncMasterN(..), Choose, (|||), ChangeLayout(..),
mirrorRect, splitVertically,
splitHorizontally, splitHorizontallyBy, splitVerticallyBy,
tile
) 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)
------------------------------------------------------------------------
-- | Change the size of the master pane.
data Resize = Shrink | Expand deriving Typeable
-- | Increase the number of clients in the master pane.
data IncMasterN = IncMasterN !Int deriving Typeable
instance Message Resize
instance Message IncMasterN
-- | Simple fullscreen mode. Renders the focused window fullscreen.
data Full a = Full deriving (Show, Read)
instance LayoutClass Full a
-- | The builtin tiling mode of xmonad. Supports 'Shrink', 'Expand' and
-- 'IncMasterN'.
data Tall a = Tall { tallNMaster :: !Int -- ^ The default number of windows in the master pane (default: 1)
, tallRatioIncrement :: !Rational -- ^ Percent of screen to increment by when resizing panes (default: 3/100)
, tallRatio :: !Rational -- ^ Default proportion of screen occupied by master pane (default: 1/2)
}
deriving (Show, Read)
-- TODO should be capped [0..1] ..
-- a nice pure layout, lots of properties for the layout, and its messages, in Properties.hs
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"
-- | Compute the positions for windows using the default two-pane tiling
-- algorithm.
--
-- The screen is divided 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.
tile
:: Rational -- ^ @frac@, what proportion of the screen to devote to the master area
-> Rectangle -- ^ @r@, the rectangle representing the screen
-> Int -- ^ @nmaster@, the number of windows in the master pane
-> Int -- ^ @n@, the total number of windows to tile
-> [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.
-- Not used in the core, but exported
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
-- Not used in the core, but exported
splitVerticallyBy f = (mirrorRect *** mirrorRect) . splitHorizontallyBy f . mirrorRect
------------------------------------------------------------------------
-- | Mirror a layout, compute its 90 degree rotated form.
newtype Mirror l a = Mirror (l a) deriving (Show, Read)
instance LayoutClass l a => LayoutClass (Mirror l) a where
runLayout (W.Workspace i (Mirror l) ms) r = (map (second mirrorRect) *** fmap Mirror)
`fmap` runLayout (W.Workspace i l ms) (mirrorRect r)
handleMessage (Mirror l) = fmap (fmap Mirror) . handleMessage l
description (Mirror l) = "Mirror "++ description l
-- | Mirror a rectangle.
mirrorRect :: Rectangle -> Rectangle
mirrorRect (Rectangle rx ry rw rh) = Rectangle ry rx rh rw
------------------------------------------------------------------------
-- LayoutClass selection manager
-- Layouts that transition between other layouts
-- | 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
(|||) = Choose L
infixr 5 |||
-- | A layout that allows users to switch between various layout options.
data Choose l r a = Choose LR (l a) (r a) deriving (Read, Show)
-- | Are we on the left or right sub-layout?
data LR = L | R deriving (Read, Show, Eq)
data NextNoWrap = NextNoWrap deriving (Eq, Show, Typeable)
instance Message NextNoWrap
-- | A small wrapper around handleMessage, as it is tedious to write
-- SomeMessage repeatedly.
handle :: (LayoutClass l a, Message m) => l a -> m -> X (Maybe (l a))
handle l m = handleMessage l (SomeMessage m)
-- | A smart constructor that takes some potential modifications, returns a
-- new structure if any fields have changed, and performs any necessary cleanup
-- on newly non-visible layouts.
choose :: (LayoutClass l a, LayoutClass r a)
=> Choose l r a-> LR -> Maybe (l a) -> Maybe (r a) -> X (Maybe (Choose l r a))
choose (Choose d _ _) d' Nothing Nothing | d == d' = return Nothing
choose (Choose d l r) d' ml mr = f lr
where
(l', r') = (fromMaybe l ml, fromMaybe r mr)
lr = case (d, d') of
(L, R) -> (hide l' , return r')
(R, L) -> (return l', hide r' )
(_, _) -> (return l', return r')
f (x,y) = fmap Just $ liftM2 (Choose d') x y
hide x = fmap (fromMaybe x) $ handle x Hide
instance (LayoutClass l a, LayoutClass r a) => LayoutClass (Choose l r) a where
runLayout (W.Workspace i (Choose L l r) ms) =
fmap (second . fmap $ flip (Choose L) r) . runLayout (W.Workspace i l ms)
runLayout (W.Workspace i (Choose R l r) ms) =
fmap (second . fmap $ Choose R l) . runLayout (W.Workspace i r ms)
description (Choose L l _) = description l
description (Choose R _ r) = description r
handleMessage lr m | Just NextLayout <- fromMessage m = do
mlr' <- handle lr NextNoWrap
maybe (handle lr FirstLayout) (return . Just) mlr'
handleMessage c@(Choose d l r) m | Just NextNoWrap <- fromMessage m =
case d of
L -> do
ml <- handle l NextNoWrap
case ml of
Just _ -> choose c L ml Nothing
Nothing -> choose c R Nothing =<< handle r FirstLayout
R -> choose c R Nothing =<< handle r NextNoWrap
handleMessage c@(Choose _ l _) m | Just FirstLayout <- fromMessage m =
flip (choose c L) Nothing =<< handle l FirstLayout
handleMessage c@(Choose d l r) m | Just ReleaseResources <- fromMessage m =
join $ liftM2 (choose c d) (handle l ReleaseResources) (handle r ReleaseResources)
handleMessage c@(Choose d l r) m = do
ml' <- case d of
L -> handleMessage l m
R -> return Nothing
mr' <- case d of
L -> return Nothing
R -> handleMessage r m
choose c d ml' mr'
