import Grid.hs into repository

Grid.hs

@@ -0,0 +1,48 @@
+-----------------------------------------------------------------------------
+-- |
+-- Module      :  XMonadContrib.Grid
+-- Copyright   :  (c) Lukas Mai
+-- License     :  BSD-style (see LICENSE)
+--
+-- Maintainer  :  <l.mai@web.de>
+-- Stability   :  unstable
+-- Portability :  unportable
+--
+--
+-----------------------------------------------------------------------------
+
+module XMonadContrib.Grid (
+	Grid(..)
+) where
+
+import XMonad
+import StackSet
+import Graphics.X11.Xlib.Types
+
+data Grid a = Grid deriving (Read, Show)
+
+instance LayoutClass Grid a where
+    pureLayout Grid r s = arrange r (integrate s)
+
+arrange :: Rectangle -> [a] -> [(a, Rectangle)]
+arrange (Rectangle rx ry rw rh) st = zip st rectangles
+	where
+	nwins = length st
+	ncols = ceiling . (sqrt :: Double -> Double) . fromIntegral $ nwins
+	mincs = nwins `div` ncols
+	extrs = nwins - ncols * mincs
+	chop :: Int -> Dimension -> [(Position, Dimension)]
+	chop n m = ((0, m - k * fromIntegral (pred n)) :) . map (flip (,) k) . tail . reverse . take n . tail . iterate (subtract k') $ m'
+		where
+		k :: Dimension
+		k = m `div` fromIntegral n
+		m' = fromIntegral m
+		k' :: Position
+		k' = fromIntegral k
+	xcoords = chop ncols rw
+	ycoords = chop mincs rh
+	ycoords' = chop (succ mincs) rh
+	(xbase, xext) = splitAt (ncols - extrs) xcoords
+	rectangles = combine ycoords xbase ++ combine ycoords' xext
+		where
+		combine ys xs = [Rectangle (rx + x) (ry + y) w h | (x, w) <- xs, (y, h) <- ys]