path: root/Warp.hs

module XMonadContrib.Warp where

{- Usage:
 - This can be used to make a keybinding that warps the pointer to a given
 - window or screen.  For example, I've added the following keybindings to
 - my Config.hs:
 - 
 -   , ((modMask,   xK_z     ), warpToWindow (1%2) (1%2)) -- @@ Move pointer to currently focused window
 - 
 - -- mod-ctrl-{w,e,r} @@ Move mouse pointer to screen 1, 2, or 3
 -    ++
 -    [((modMask .|. controlMask, key), warpToScreen sc (1%2) (1%2))
 -        | (key, sc) <- zip [xK_w, xK_e, xK_r] [0..]]
 -
 - Note that warping to a particular screen may change the focus.
 -}

import Data.Ratio
import Data.Maybe
import Control.Monad.RWS
import Graphics.X11.Xlib
import Graphics.X11.Xlib.Extras
import Operations
import XMonad

fraction :: (Integral a, Integral b) => Rational -> a -> b
fraction f x = floor (f * fromIntegral x)

ix :: Int -> [a] -> Maybe a
ix n = listToMaybe . take 1 . drop n

warp :: Window -> Position -> Position -> X ()
warp w x y = withDisplay $ \d -> io $ warpPointer d none w 0 0 0 0 x y

warpToWindow :: Rational -> Rational -> X ()
warpToWindow h v =
    withDisplay $ \d ->
        withFocused $ \w -> do
            wa <- io $ getWindowAttributes d w
            warp w (fraction h (wa_width wa)) (fraction v (wa_height wa))

warpToScreen :: Int -> Rational -> Rational -> X ()
warpToScreen n h v = do
    xScreens <- gets xineScreens
    root     <- asks theRoot
    whenJust (ix n xScreens) $ \r ->
        warp root (rect_x r + fraction h (rect_width  r))
                  (rect_y r + fraction v (rect_height r))