{-# OPTIONS_GHC -fno-warn-name-shadowing -fno-warn-unused-binds #-}
{-# LANGUAGE FlexibleInstances, MultiParamTypeClasses
, PatternGuards, DeriveDataTypeable, ExistentialQuantification
, FlexibleContexts #-}
-----------------------------------------------------------------------------
-- |
-- Module : XMonad.Layout.ZoomRow
-- Copyright : Quentin Moser <moserq@gmail.com>
-- License : BSD-style (see LICENSE)
--
-- Maintainer : orphaned
-- Stability : unstable
-- Portability : unportable
--
-- Row layout with individually resizable elements.
--
-----------------------------------------------------------------------------
module XMonad.Layout.ZoomRow ( -- * Usage
-- $usage
ZoomRow
-- * Creation
, zoomRow
-- * Messages
, ZoomMessage(..)
, zoomIn
, zoomOut
, zoomReset
-- * Use with non-'Eq' elements
-- $noneq
, zoomRowWith
, EQF(..)
, ClassEQ(..)
) where
import XMonad
import qualified XMonad.StackSet as W
import XMonad.Util.Stack
import XMonad.Layout.Decoration (fi)
import Data.Maybe (fromMaybe)
import Control.Arrow (second)
-- $usage
-- This module provides a layout which places all windows in a single
-- row; the size occupied by each individual window can be increased
-- and decreased, and a window can be set to use the whole available
-- space whenever it has focus.
--
-- You can use this module by including the following in your @~\/.xmonad/xmonad.hs@:
--
-- > import XMonad.Layout.ZoomRow
--
-- and using 'zoomRow' somewhere in your 'layoutHook', for example:
--
-- > myLayout = zoomRow ||| Mirror zoomRow
--
-- To be able to resize windows, you can create keybindings to send
-- the relevant 'ZoomMessage's:
--
-- > -- Increase the size occupied by the focused window
-- > , ((modMask .|. shifMask, xK_minus), sendMessage zoomIn)
-- > -- Decrease the size occupied by the focused window
-- > , ((modMayk , xK_minus), sendMessage zoomOut)
-- > -- Reset the size occupied by the focused window
-- > , ((modMask , xK_equal), sendMessage zoomReset)
-- > -- (Un)Maximize the focused window
-- > , ((modMask , xK_f ), sendMessage ToggleZoomFull)
--
-- For more information on editing your layout hook and key bindings,
-- see "XMonad.Doc.Extending".
-- * Creation functions
-- | 'ZoomRow' layout for laying out elements which are instances of
-- 'Eq'. Perfect for 'Window's.
zoomRow :: (Eq a, Show a, Read a) => ZoomRow ClassEQ a
zoomRow = ZC ClassEQ emptyZ
-- $noneq
-- Haskell's 'Eq' class is usually concerned with structural equality, whereas
-- what this layout really wants is for its elements to have a unique identity,
-- even across changes. There are cases (such as, importantly, 'Window's) where
-- the 'Eq' instance for a type actually does that, but if you want to lay
-- out something more exotic than windows and your 'Eq' means something else,
-- you can use the following.
-- | ZoomRow layout with a custom equality predicate. It should
-- of course satisfy the laws for 'Eq', and you should also make
-- sure that the layout never has to handle two \"equal\" elements
-- at the same time (it won't do any huge damage, but might behave
-- a bit strangely).
zoomRowWith :: (EQF f a, Show (f a), Read (f a), Show a, Read a)
=> f a -> ZoomRow f a
zoomRowWith f = ZC f emptyZ
-- * The datatypes
-- | A layout that arranges its windows in a horizontal row,
-- and allows to change the relative size of each element
-- independently.
data ZoomRow f a = ZC { zoomEq :: f a
-- ^ Function to compare elements for
-- equality, a real Eq instance might
-- not be what you want in some cases
, zoomRatios :: (Zipper (Elt a))
-- ^ Element specs. The zipper is so we
-- know what the focus is when we handle
-- a message
}
deriving (Show, Read, Eq)
-- | Class for equivalence relations. Must be transitive, reflexive.
class EQF f a where
eq :: f a -> a -> a -> Bool
-- | To use the usual '==':
data ClassEQ a = ClassEQ
deriving (Show, Read, Eq)
instance Eq a => EQF ClassEQ a where
eq _ a b = a == b
-- | Size specification for an element.
data Elt a = E { elt :: a -- ^ The element
, ratio :: Rational -- ^ Its size ratio
, full :: Bool -- ^ Whether it should occupy all the
-- available space when it has focus.
}
deriving (Show, Read, Eq)
-- * Helpers
getRatio :: Elt a -> (a, Rational)
getRatio (E a r _) = (a,r)
lookupBy :: (a -> a -> Bool) -> a -> [Elt a] -> Maybe (Elt a)
lookupBy _ _ [] = Nothing
lookupBy f a (E a' r b : _) | f a a' = Just $ E a r b
lookupBy f a (_:es) = lookupBy f a es
setFocus :: Zipper a -> a -> Zipper a
setFocus Nothing a = Just $ W.Stack a [] []
setFocus (Just s) a = Just s { W.focus = a }
-- * Messages
-- | The type of messages accepted by a 'ZoomRow' layout
data ZoomMessage = Zoom Rational
-- ^ Multiply the focused window's size factor
-- by the given number.
| ZoomTo Rational
-- ^ Set the focused window's size factor to the
-- given number.
| ZoomFull Bool
-- ^ Set whether the focused window should occupy
-- all available space when it has focus
| ZoomFullToggle
-- ^ Toggle whether the focused window should
-- occupy all available space when it has focus
deriving (Typeable, Show)
instance Message ZoomMessage
-- | Increase the size of the focused window.
-- Defined as @Zoom 1.5@
zoomIn :: ZoomMessage
zoomIn = Zoom 1.5
-- | Decrease the size of the focused window.
-- Defined as @Zoom (2/3)@
zoomOut :: ZoomMessage
zoomOut = Zoom $ 2/3
-- | Reset the size of the focused window.
-- Defined as @ZoomTo 1@
zoomReset :: ZoomMessage
zoomReset = ZoomTo 1
-- * LayoutClass instance
instance (EQF f a, Show a, Read a, Show (f a), Read (f a))
=> LayoutClass (ZoomRow f) a where
description (ZC _ Nothing) = "ZoomRow"
description (ZC _ (Just s)) = "ZoomRow" ++ if full $ W.focus s
then " (Max)"
else ""
emptyLayout (ZC _ Nothing) _ = return ([], Nothing)
emptyLayout (ZC f _) _ = return ([], Just $ ZC f Nothing)
doLayout (ZC f zelts) r@(Rectangle _ _ w _) s
= let elts = W.integrate' zelts
zelts' = mapZ_ (\a -> fromMaybe (E a 1 False)
$ lookupBy (eq f) a elts) $ Just s
elts' = W.integrate' zelts'
maybeL' = if zelts `noChange` zelts'
then Nothing
else Just $ ZC f zelts'
total = sum $ map ratio elts'
widths = map (second ((* fi w) . (/total)) . getRatio) elts'
in case getFocusZ zelts' of
Just (E a _ True) -> return ([(a, r)], maybeL')
_ -> return (makeRects r widths, maybeL')
where makeRects :: Rectangle -> [(a, Rational)] -> [(a, Rectangle)]
makeRects r pairs = let as = map fst pairs
widths = map snd pairs
discreteWidths = snd $ foldr discretize (0, []) widths
rectangles = snd $ foldr makeRect (r, []) discreteWidths
in zip as rectangles
-- | Make a new rectangle by substracting the given width from the available
-- space (from the right, since this is a foldr)
makeRect :: Dimension -> (Rectangle, [Rectangle]) -> (Rectangle, [Rectangle])
makeRect w (Rectangle x y w0 h, rs) = ( Rectangle x y (w0-w) h
, Rectangle (x+fi w0-fi w) y w h : rs )
-- | Round a list of fractions in a way that maintains the total.
-- If you know a better way to do this I'm very interested.
discretize :: Rational -> (Rational, [Dimension]) -> (Rational, [Dimension])
discretize r (carry, ds) = let (d, carry') = properFraction $ carry+r
in (carry', d:ds)
noChange z1 z2 = toTags z1 `helper` toTags z2
where helper [] [] = True
helper (Right a:as) (Right b:bs) = a `sameAs` b && as `helper` bs
helper (Left a:as) (Left b:bs) = a `sameAs` b && as `helper` bs
helper _ _ = False
E a1 r1 b1 `sameAs` E a2 r2 b2 = (eq f a1 a2) && (r1 == r2) && (b1 == b2)
pureMessage (ZC f zelts) sm | Just (ZoomFull False) <- fromMessage sm
, Just (E a r True) <- getFocusZ zelts
= Just $ ZC f $ setFocus zelts $ E a r False
pureMessage (ZC f zelts) sm | Just (ZoomFull True) <- fromMessage sm
, Just (E a r False) <- getFocusZ zelts
= Just $ ZC f $ setFocus zelts $ E a r True
pureMessage (ZC f zelts) sm | Just (E a r b) <- getFocusZ zelts
= case fromMessage sm of
Just (Zoom r') -> Just $ ZC f $ setFocus zelts $ E a (r*r') b
Just (ZoomTo r') -> Just $ ZC f $ setFocus zelts $ E a r' b
Just ZoomFullToggle -> pureMessage (ZC f zelts)
$ SomeMessage $ ZoomFull $ not b
_ -> Nothing
pureMessage _ _ = Nothing
