    -----------------------------------------------------------------------------
    -- |
    -- Module       : XMonad.Actions.FloatKeys
    -- Copyright    : (c) Karsten Schoelzel <kuser@gmx.de>
    -- License      : BSD
    --
    -- Maintainer   : Karsten Schoelzel <kuser@gmx.de>
    -- Stability    : stable
    -- Portability  : unportable
    --
    -- Move and resize floating windows.
    -----------------------------------------------------------------------------

    module XMonad.Actions.FloatKeys (
                    -- * Usage
                    -- $usage
                    keysMoveWindow,
                    keysMoveWindowTo,
                    keysResizeWindow,
                    keysAbsResizeWindow,
                    P, G,
                    ) where

    import XMonad

    -- $usage
    -- You can use this module with the following in your @~\/.xmonad\/xmonad.hs@:
    --
    -- >    import XMonad.Actions.FloatKeys
    --
    -- Then add appropriate key bindings, for example:
    --
    -- >  , ((modm,               xK_d     ), withFocused (keysResizeWindow (-10,-10) (1,1)))
    -- >  , ((modm,               xK_s     ), withFocused (keysResizeWindow (10,10) (1,1)))
    -- >  , ((modm .|. shiftMask, xK_d     ), withFocused (keysAbsResizeWindow (-10,-10) (1024,752)))
    -- >  , ((modm .|. shiftMask, xK_s     ), withFocused (keysAbsResizeWindow (10,10) (1024,752)))
    -- >  , ((modm,               xK_a     ), withFocused (keysMoveWindowTo (512,384) (1%2,1%2)))
    --
    -- For detailed instructions on editing your key bindings, see
    -- "XMonad.Doc.Extending#Editing_key_bindings".

    -- | @keysMoveWindow (dx, dy)@ moves the window by @dx@ pixels to the
    --   right and @dy@ pixels down.
    keysMoveWindow :: D -> Window -> X ()
    keysMoveWindow (dx,dy) w = whenX (isClient w) $ withDisplay $ \d -> do
        io $ raiseWindow d w
        wa <- io $ getWindowAttributes d w
        io $ moveWindow d w (fromIntegral (fromIntegral (wa_x wa) + dx))
                            (fromIntegral (fromIntegral (wa_y wa) + dy))
        float w

    -- | @keysMoveWindowTo (x, y) (gx, gy)@ moves the window relative
    --   point @(gx, gy)@ to the point @(x,y)@, where @(gx,gy)@ gives a
    --   position relative to the window border, i.e.  @gx = 0@ is the left
    --   border, @gx = 1@ is the right border, @gy = 0@ is the top border, and
    --   @gy = 1@ the bottom border.
    --
    --   For example, on a 1024x768 screen:
    --
    -- > keysMoveWindowTo (512,384) (1%2, 1%2) -- center the window on screen
    -- > keysMoveWindowTo (1024,0) (1, 0)      -- put window in the top right corner
    keysMoveWindowTo :: P -> G -> Window -> X ()
    keysMoveWindowTo (x,y) (gx, gy) w = whenX (isClient w) $ withDisplay $ \d -> do
        io $ raiseWindow d w
        wa <- io $ getWindowAttributes d w
        io $ moveWindow d w (x - round (gx * fromIntegral (wa_width wa)))
                            (y - round (gy * fromIntegral (wa_height wa)))
        float w

    type G = (Rational, Rational)
    type P = (Position, Position)

    -- | @keysResizeWindow (dx, dy) (gx, gy)@ changes the width by @dx@
    --   and the height by @dy@, leaving the window-relative point @(gx,
    --   gy)@ fixed.
    --
    --   For example:
    --
    -- > keysResizeWindow (10, 0) (0, 0)      -- make the window 10 pixels larger to the right
    -- > keysResizeWindow (10, 0) (0, 1%2)    -- does the same, unless sizeHints are applied
    -- > keysResizeWindow (10, 10) (1%2, 1%2) -- add 5 pixels on each side
    -- > keysResizeWindow (-10, -10) (0, 1)   -- shrink the window in direction of the bottom-left corner
    keysResizeWindow :: D -> G -> Window -> X ()
    keysResizeWindow = keysMoveResize keysResizeWindow'

    -- | @keysAbsResizeWindow (dx, dy) (ax, ay)@ changes the width by @dx@
    --   and the height by @dy@, leaving the screen absolute point @(ax,
    --   ay)@ fixed.
    --
    --   For example:
    --
    -- > keysAbsResizeWindow (10, 10) (0, 0)   -- enlarge the window; if it is not in the top-left corner it will also be moved down and to the right.
    keysAbsResizeWindow :: D -> D -> Window -> X ()
    keysAbsResizeWindow = keysMoveResize keysAbsResizeWindow'

    keysAbsResizeWindow' :: SizeHints -> P -> D -> D -> D -> (P,D)
    keysAbsResizeWindow' sh (x,y) (w,h) (dx,dy) (ax, ay) = ((round nx, round ny), (nw, nh))
        where
            (nw, nh) = applySizeHintsContents sh (w + dx, h + dy)
            nx :: Rational
            nx = fromIntegral (ax * w + nw * (fromIntegral x - ax)) / fromIntegral w
            ny :: Rational
            ny = fromIntegral (ay * h + nh * (fromIntegral y - ay)) / fromIntegral h

    keysResizeWindow' :: SizeHints -> P -> D -> D -> G -> (P,D)
    keysResizeWindow' sh (x,y) (w,h) (dx,dy) (gx, gy) = ((nx, ny), (nw, nh))
        where
            (nw, nh) = applySizeHintsContents sh (w + dx, h + dy)
            nx = round $ fromIntegral x + gx * fromIntegral w - gx * fromIntegral nw
            ny = round $ fromIntegral y + gy * fromIntegral h - gy * fromIntegral nh

    keysMoveResize :: (SizeHints -> P -> D -> a -> b -> (P,D)) -> a -> b -> Window -> X ()
    keysMoveResize f move resize w = whenX (isClient w) $ withDisplay $ \d -> do
        io $ raiseWindow d w
        wa <- io $ getWindowAttributes d w
        sh <- io $ getWMNormalHints d w
        let wa_dim = (fromIntegral $ wa_width wa, fromIntegral $ wa_height wa)
            wa_pos = (fromIntegral $ wa_x wa, fromIntegral $ wa_y wa)
            (wn_pos, wn_dim) = f sh wa_pos wa_dim move resize
        io $ resizeWindow d w `uncurry` wn_dim
        io $ moveWindow d w `uncurry` wn_pos
        float w