content: {-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, PatternGuards #-}
  -----------------------------------------------------------------------------
  -- |
  -- Module      :  XMonad.Layout.ResizeScreen
  -- Copyright   :  (c) 2007 Andrea Rossato
  -- License     :  BSD-style (see xmonad/LICENSE)
  --
  -- Maintainer  :  andrea.rossato@unibz.it
  -- Stability   :  unstable
  -- Portability :  unportable
  --
  -- A layout transformer to have a layout respect a given screen
  -- geometry. Mostly used with "Decoration" (the Horizontal and the
  -- Vertical version will react to SetTheme and change their dimension
  -- accordingly.
  -----------------------------------------------------------------------------
  
  module XMonad.Layout.ResizeScreen
      ( -- * Usage:
        -- $usage
        resizeHorizontal, resizeVertical
      , resizeHorizontalRight, resizeVerticalBottom
      , withNewRectangle
      , ResizeScreen (..)
      , ResizeMode
      ) where
  
  import XMonad
  import XMonad.Layout.Decoration
  
  -- $usage
  -- You can use this module by importing it into your
  -- @~\/.xmonad\/xmonad.hs@ file:
  --
  -- > import XMonad.Layout.ResizeScreen
  --
  -- and modifying your layoutHook as follows (for example):
  --
  -- > layoutHook = resizeHorizontal 40 Full
  --
  -- For more detailed instructions on editing the layoutHook see:
  --
  -- "XMonad.Doc.Extending#Editing_the_layout_hook"
  
  resizeHorizontal :: Int -> l a -> ModifiedLayout ResizeScreen l a
  resizeHorizontal i = ModifiedLayout (ResizeScreen L i)
  
  resizeVertical :: Int -> l a -> ModifiedLayout ResizeScreen l a
  resizeVertical i = ModifiedLayout (ResizeScreen T i)
  
  resizeHorizontalRight :: Int -> l a -> ModifiedLayout ResizeScreen l a
  resizeHorizontalRight i = ModifiedLayout (ResizeScreen R i)
  
  resizeVerticalBottom :: Int -> l a -> ModifiedLayout ResizeScreen l a
  resizeVerticalBottom i = ModifiedLayout (ResizeScreen B i)
  
  withNewRectangle  :: Rectangle -> l a -> ModifiedLayout ResizeScreen l a
  withNewRectangle r = ModifiedLayout (WithNewScreen r)
  
  data ResizeScreen a = ResizeScreen ResizeMode Int
                      | WithNewScreen Rectangle
                        deriving (Read, Show)
  
  data ResizeMode = T | B | L | R deriving (Read, Show)
  
  instance LayoutModifier ResizeScreen a where
      modifyLayout m ws rect@(Rectangle x y w h)
          | ResizeScreen L i <- m = resize $ Rectangle (x + fi i) y (w - fi i) h
          | ResizeScreen R i <- m = resize $ Rectangle x          y (w - fi i) h
          | ResizeScreen T i <- m = resize $ Rectangle x (y + fi i) w (h - fi i)
          | ResizeScreen B i <- m = resize $ Rectangle x  y         w (h - fi i)
          | WithNewScreen  r <- m = resize r
          | otherwise             = resize rect
         where resize nr = runLayout ws nr
  
      pureMess (ResizeScreen d _) m
          | Just (SetTheme t) <- fromMessage m = Just $ ResizeScreen d (fi $ decoHeight t)
      pureMess _ _ = Nothing
  