aboutsummaryrefslogtreecommitdiffstats
path: root/XMonad/Layout/LayoutHints.hs
blob: 29a7d3d854a644e4f9f5b46340d08ef6177ff54e (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses, TypeSynonymInstances #-}
{-# LANGUAGE ParallelListComp, PatternGuards #-}
-----------------------------------------------------------------------------
-- |
-- Module       : XMonad.Layout.LayoutHints
-- Copyright    : (c) David Roundy <droundy@darcs.net>
-- License      : BSD
--
-- Maintainer   : none
-- Stability    : unstable
-- Portability  : unportable
--
-- Make layouts respect size hints.
-----------------------------------------------------------------------------

module XMonad.Layout.LayoutHints
    ( -- * usage
      -- $usage
      layoutHints
    , layoutHintsWithPlacement
    , layoutHintsToCenter
    , LayoutHints
    )  where

import XMonad(LayoutClass(runLayout), mkAdjust, Window,
              Dimension, Position, Rectangle(Rectangle),D)
import qualified XMonad.StackSet as W

import XMonad.Layout.Decoration(isInStack)
import XMonad.Layout.LayoutModifier(ModifiedLayout(..),
                                    LayoutModifier(modifyLayout, redoLayout, modifierDescription))
import XMonad.Util.Types(Direction2D(..))
import Control.Applicative((<$>))
import Control.Arrow(Arrow((***), first, second))
import Control.Monad(Monad(return), mapM, join)
import Data.Function(on)
import Data.List(sortBy)

import Data.Set (Set)
import qualified Data.Set as Set

-- $usage
-- You can use this module with the following in your @~\/.xmonad\/xmonad.hs@:
--
-- > import XMonad.Layout.LayoutHints
--
-- Then edit your @layoutHook@ by adding the 'layoutHints' layout modifier
-- to some layout:
--
-- > myLayouts = layoutHints (Tall 1 (3/100) (1/2))  ||| Full ||| etc..
-- > main = xmonad defaultConfig { layoutHook = myLayouts }
--
-- Or, to center the adapted window in its available area:
--
-- > myLayouts = layoutHintsWithPlacement (0.5, 0.5) (Tall 1 (3/100) (1/2))
-- >                   ||| Full ||| etc..
--
-- Or, to make a reasonable attempt to eliminate gaps between windows:
--
-- > myLayouts = layoutHintsToCenter (Tall 1 (3/100) (1/2))
--
-- For more detailed instructions on editing the layoutHook see:
--
-- "XMonad.Doc.Extending#Editing_the_layout_hook"

layoutHints :: (LayoutClass l a) => l a -> ModifiedLayout LayoutHints l a
layoutHints = ModifiedLayout (LayoutHints (0, 0))

-- | @layoutHintsWithPlacement (rx, ry) layout@ will adapt the sizes of a layout's
-- windows according to their size hints, and position them inside their
-- originally assigned area according to the @rx@ and @ry@ parameters.
-- (0, 0) places the window at the top left, (1, 0) at the top right, (0.5, 0.5)
-- at the center, etc.
layoutHintsWithPlacement :: (LayoutClass l a) => (Double, Double)
                         -> l a -> ModifiedLayout LayoutHints l a
layoutHintsWithPlacement rs = ModifiedLayout (LayoutHints rs)

-- | @layoutHintsToCenter layout@ applies hints, sliding the window to the
-- center of the screen and expanding its neighbors to fill the gaps. Windows
-- are never expanded in a way that increases overlap.
--
-- @layoutHintsToCenter@ only makes one pass at resizing the neighbors of
-- hinted windows, so with some layouts (ex. the arrangement with two 'Mirror'
-- 'Tall' stacked vertically), @layoutHintsToCenter@ may leave some gaps.
-- Simple layouts like 'Tall' are unaffected.
layoutHintsToCenter :: (LayoutClass l a) => l a -> ModifiedLayout LayoutHintsToCenter l a
layoutHintsToCenter = ModifiedLayout LayoutHintsToCenter

data LayoutHints a = LayoutHints (Double, Double)
                     deriving (Read, Show)

instance LayoutModifier LayoutHints Window where
    modifierDescription _ = "Hinted"
    redoLayout _ _ Nothing  xs = return (xs, Nothing)
    redoLayout (LayoutHints al) _ (Just s) xs
        = do xs' <- mapM (\x@(_, r) -> second (placeRectangle al r) <$> applyHint x) xs
             return (xs', Nothing)
     where
        applyHint (w,r@(Rectangle a b c d)) = do
            adj <- mkAdjust w
            let (c',d') = adj (c,d)
            return (w, if isInStack s w then Rectangle a b c' d' else r)

-- | @placeRectangle (rx, ry) r0 r@ will return a new rectangle with the same dimensions
-- as @r@, but positioned inside of @r0@ as specified by the (rx, ry) parameters (see
-- 'layoutHintsWithPlacement').
placeRectangle :: RealFrac r => (r, r) -> Rectangle -> Rectangle -> Rectangle
placeRectangle (rx, ry) (Rectangle x0 y0 w h) (Rectangle _ _ dx dy)
    = Rectangle (align x0 dx w rx) (align y0 dy h ry) dx dy
    where align :: RealFrac r => Position -> Dimension -> Dimension -> r -> Position
          align z0 dz d r = z0 + truncate (fromIntegral (d - dz) * r)

fitting :: [Rectangle] -> Int
fitting rects = sum $ do
    r <- rects
    return $ length $ filter (touching r) rects

applyOrder :: Rectangle -> [((Window, Rectangle),t)] -> [[((Window, Rectangle),t)]]
applyOrder root wrs = do
    -- perhaps it would just be better to take all permutations, or apply the
    -- resizing multiple times
    f <- [maximum, minimum, sum, sum . map sq]
    return $ sortBy (compare `on` (f . distance)) wrs
    where distFC = uncurry ((+) `on` sq) . pairWise (-) (center root)
          distance = map distFC . corners . snd . fst
          pairWise f (a,b) (c,d) = (f a c, f b d)
          sq = join (*)

data LayoutHintsToCenter a = LayoutHintsToCenter deriving (Read, Show)

instance LayoutModifier LayoutHintsToCenter Window where
    modifyLayout _ ws@(W.Workspace _ _ Nothing) r = runLayout ws r
    modifyLayout _ ws@(W.Workspace _ _ (Just st)) r = do
        (arrs,ol) <- runLayout ws r
        flip (,) ol
            . head . reverse . sortBy (compare `on` (fitting . map snd))
            . map (applyHints st r) . applyOrder r
            <$> mapM (\x -> fmap ((,) x) $ mkAdjust (fst x)) arrs

-- apply hints to first, grow adjacent windows
applyHints :: W.Stack Window -> Rectangle -> [((Window, Rectangle),(D -> D))] -> [(Window, Rectangle)]
applyHints _ _ [] = []
applyHints s root (((w,lrect@(Rectangle a b c d)),adj):xs) =
        let (c',d') = adj (c,d)
            redr = placeRectangle (centerPlacement root lrect :: (Double,Double)) lrect
                    $ if isInStack s w then Rectangle a b c' d' else lrect

            ds = (fromIntegral c - fromIntegral c',fromIntegral d - fromIntegral d')
            growOther' r = growOther ds lrect (freeDirs root lrect) r
            mapSnd f = map (first $ second f)
            next = applyHints s root $ mapSnd growOther' xs
        in (w,redr):next

growOther :: (Position, Position) -> Rectangle -> Set Direction2D -> Rectangle -> Rectangle
growOther ds lrect fds r
    | dirs <- flipDir <$> Set.toList (Set.intersection adj fds)
    , not $ any (uncurry opposite) $ cross dirs =
        foldr (flip grow ds) r dirs
    | otherwise = r
    where
        adj = adjacent lrect  r
        cross xs = [ (a,b) | a <- xs, b <- xs ]

        flipDir :: Direction2D -> Direction2D
        flipDir d = case d of { L -> R; U -> D; R -> L; D -> U }

        opposite :: Direction2D -> Direction2D -> Bool
        opposite x y = flipDir x == y

-- | Leave the opposite edges where they were
grow :: Direction2D -> (Position,Position) -> Rectangle -> Rectangle
grow L (px,_ ) (Rectangle x y w h) = Rectangle (x-px) y (w+fromIntegral px) h
grow U (_ ,py) (Rectangle x y w h) = Rectangle x (y-py) w (h+fromIntegral py)
grow R (px,_ ) (Rectangle x y w h) = Rectangle x y (w+fromIntegral px) h
grow D (_ ,py) (Rectangle x y w h) = Rectangle x y w (h+fromIntegral py)

comparingEdges :: ([Position] -> [Position] -> Bool) -> Rectangle -> Rectangle -> Set Direction2D
comparingEdges surrounds r1 r2 = Set.fromList $ map fst $ filter snd [ (\k -> (dir,k)) $
            any and [[dir `elem` [R,L], allEq [a,c,w,y], [b,d] `surrounds` [x,z]]
                    ,[dir `elem` [U,D], allEq [b,d,x,z], [a,c] `surrounds` [w,y]]]
    | ((a,b),(c,d)) <- edge $ corners r1
    | ((w,x),(y,z)) <- edge $ delay 2 $ corners r2
    | dir <- [U,R,D,L]]
        where edge (x:xs) = zip (x:xs) (xs ++ [x])
              edge [] = []
              delay n xs = drop n xs ++ take n xs
              allEq = all (uncurry (==)) . edge

-- | in what direction is the second window from the first that can expand if the
-- first is shrunk, assuming that the root window is fully covered:
--  one direction for a common edge
--  two directions for a common corner
adjacent :: Rectangle -> Rectangle -> Set Direction2D
adjacent = comparingEdges (all . onClosedInterval)

-- | True whenever two edges touch. not (Set.null $ adjacent x y) ==> touching x y
touching :: Rectangle -> Rectangle -> Bool
touching a b = not . Set.null $ comparingEdges c a b
    where c x y = any (onClosedInterval x) y || any (onClosedInterval y) x

onClosedInterval :: Ord a => [a] -> a -> Bool
onClosedInterval bds x = minimum bds <= x && maximum bds >= x

-- | starting top left going clockwise
corners :: Rectangle -> [(Position, Position)]
corners (Rectangle x y w h) = [(x,y)
                              ,(x+fromIntegral w, y)
                              ,(x+fromIntegral w, y+fromIntegral h)
                              ,(x, y+fromIntegral h)]

center :: Rectangle -> (Position, Position)
center (Rectangle x y w h) = (avg x w, avg y h)
    where avg a b = a + fromIntegral b `div` 2

centerPlacement :: RealFrac r => Rectangle -> Rectangle -> (r, r)
centerPlacement = centerPlacement' clamp
    where clamp n = case signum n of
                            0 -> 0.5
                            1 -> 1
                            _ -> 0

freeDirs :: Rectangle -> Rectangle -> Set Direction2D
freeDirs root = Set.fromList . uncurry (++) . (lr *** ud)
              . centerPlacement' signum root
    where
        lr 1 = [L]
        lr (-1) = [R]
        lr _ = [L,R]
        ud 1 = [U]
        ud (-1) = [D]
        ud _ = [U,D]

centerPlacement' :: (Position -> r) -> Rectangle -> Rectangle -> (r, r)
centerPlacement' cf root assigned
    = (cf $ cx - cwx, cf $ cy - cwy)
    where (cx,cy) = center root
          (cwx,cwy) = center assigned