```{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}

-----------------------------------------------------------------------------
-- |
-- Copyright   :  (c) Peter De Wachter
--
-- Maintainer  :  Peter De Wachter <pdewacht@gmail.com>
-- Stability   :  unstable
-- Portability :  unportable
--
-- Circle is an elliptical, overlapping layout, by Peter De Wachter
--
-----------------------------------------------------------------------------

-- * Usage
-- \$usage
Circle (..)
) where -- actually it's an ellipse

import Data.List

-- \$usage
--
--
--
-- > myLayout = Circle ||| Full ||| etc..
-- > main = xmonad def { layoutHook = myLayout }
--
-- For more detailed instructions on editing the layoutHook see:
--

data Circle a = Circle deriving ( Read, Show )

instance LayoutClass Circle Window where
doLayout Circle r s = do layout <- raiseFocus \$ circleLayout r \$ integrate s
return (layout, Nothing)

circleLayout :: Rectangle -> [a] -> [(a, Rectangle)]
circleLayout _ []     = []
circleLayout r (w:ws) = master : rest
where master = (w, center r)
rest   = zip ws \$ map (satellite r) [0, pi * 2 / fromIntegral (length ws) ..]

raiseFocus :: [(Window, Rectangle)] -> X [(Window, Rectangle)]
raiseFocus xs = do focused <- withWindowSet (return . peek)
return \$ case find ((== focused) . Just . fst) xs of
Just x  -> x : delete x xs
Nothing -> xs

center :: Rectangle -> Rectangle
center (Rectangle sx sy sw sh) = Rectangle x y w h
where s = sqrt 2 :: Double
w = round (fromIntegral sw / s)
h = round (fromIntegral sh / s)
x = sx + fromIntegral (sw - w) `div` 2
y = sy + fromIntegral (sh - h) `div` 2

satellite :: Rectangle -> Double -> Rectangle
satellite (Rectangle sx sy sw sh) a = Rectangle (sx + round (rx + rx * cos a))
(sy + round (ry + ry * sin a))
w h
where rx = fromIntegral (sw - w) / 2
ry = fromIntegral (sh - h) / 2
w = sw * 10 `div` 25
h = sh * 10 `div` 25

```