-----------------------------------------------------------------------------
-- |
-- Module : XMonad.Actions.MouseGestures
-- Copyright : (c) Lukas Mai
-- License : BSD3-style (see LICENSE)
--
-- Maintainer : <l.mai@web.de>
-- Stability : unstable
-- Portability : unportable
--
-- Support for simple mouse gestures.
--
-----------------------------------------------------------------------------
module XMonad.Actions.MouseGestures (
-- * Usage
-- $usage
Direction(..),
mouseGestureH,
mouseGesture,
mkCollect
) where
import XMonad
import XMonad.Layout.WindowNavigation (Direction(..))
import Data.IORef
import qualified Data.Map as M
import Data.Map (Map)
import Data.Maybe
import Control.Monad
-- $usage
--
-- You can use this module with the following in your @~\/.xmonad\/xmonad.hs@:
--
-- > import XMonad.Actions.MouseGestures
-- > import qualified XMonad.StackSet as W
--
-- then add an appropriate mouse binding:
--
-- > , ((modMask x .|. shiftMask, button3), mouseGesture gestures)
--
-- where @gestures@ is a 'Data.Map.Map' from gestures to actions on
-- windows, for example:
--
-- > gestures = M.fromList
-- > [ ([], focus)
-- > , ([U], \w -> focus w >> windows W.swapUp)
-- > , ([D], \w -> focus w >> windows W.swapDown)
-- > , ([R, D], \_ -> sendMessage NextLayout)
-- > ]
--
-- This is just an example, of course; you can use any mouse button and
-- gesture definitions you want.
--
-- For detailed instructions on editing your mouse bindings, see
-- "XMonad.Doc.Extending#Editing_mouse_bindings".
type Pos = (Position, Position)
delta :: Pos -> Pos -> Position
delta (ax, ay) (bx, by) = max (d ax bx) (d ay by)
where
d a b = abs (a - b)
dir :: Pos -> Pos -> Direction
dir (ax, ay) (bx, by) = trans . (/ pi) $ atan2 (fromIntegral $ ay - by) (fromIntegral $ bx - ax)
where
trans :: Double -> Direction
trans x
| rg (-3/4) (-1/4) x = D
| rg (-1/4) (1/4) x = R
| rg (1/4) (3/4) x = U
| otherwise = L
rg a z x = a <= x && x < z
gauge :: (Direction -> X ()) -> Pos -> IORef (Maybe (Direction, Pos)) -> Position -> Position -> X ()
gauge hook op st nx ny = do
let np = (nx, ny)
stx <- io $ readIORef st
let
(~(Just od), pivot) = case stx of
Nothing -> (Nothing, op)
Just (d, zp) -> (Just d, zp)
cont = do
guard $ significant np pivot
return $ do
let d' = dir pivot np
when (isNothing stx || od /= d') $ hook d'
io $ writeIORef st (Just (d', np))
fromMaybe (return ()) cont
where
significant a b = delta a b >= 10
-- | @'mouseGestureH' moveHook endHook@ is a mouse button
-- event handler. It collects mouse movements, calling @moveHook@ for each
-- update; when the button is released, it calls @endHook@.
mouseGestureH :: (Direction -> X ()) -> X () -> X ()
mouseGestureH moveHook endHook = do
dpy <- asks display
root <- asks theRoot
(pos, acc) <- io $ do
(_, _, _, ix, iy, _, _, _) <- queryPointer dpy root
r <- newIORef Nothing
return ((fromIntegral ix, fromIntegral iy), r)
mouseDrag (gauge moveHook pos acc) endHook
-- | A utility function on top of 'mouseGestureH'. It uses a 'Data.Map.Map' to
-- look up the mouse gesture, then executes the corresponding action (if any).
mouseGesture :: Map [Direction] (Window -> X ()) -> Window -> X ()
mouseGesture tbl win = do
(mov, end) <- mkCollect
mouseGestureH (\d -> mov d >> return ()) $ end >>= \gest ->
case M.lookup gest tbl of
Nothing -> return ()
Just f -> f win
-- | A callback generator for 'mouseGestureH'. 'mkCollect' returns two
-- callback functions for passing to 'mouseGestureH'. The move hook will
-- collect mouse movements (and return the current gesture as a list); the end
-- hook will return a list of the completed gesture, which you can access with
-- 'Control.Monad.>>='.
mkCollect :: (MonadIO m, MonadIO m') => m (Direction -> m' [Direction], m' [Direction])
mkCollect = liftIO $ do
acc <- newIORef []
let
mov d = liftIO $ do
ds <- readIORef acc
let ds' = d : ds
writeIORef acc ds'
return $ reverse ds'
end = liftIO $ do
ds <- readIORef acc
writeIORef acc []
return $ reverse ds
return (mov, end)
