ltk-0.13.1.0: src/Graphics/UI/Editor/Basics.hs
{-# LANGUAGE MultiParamTypeClasses, ScopedTypeVariables, FlexibleContexts, RankNTypes,
ExistentialQuantification, TypeFamilies, ImpredicativeTypes #-}
-----------------------------------------------------------------------------
--
-- Module : Graphics.UI.Editor.Basics
-- Copyright : (c) Juergen Nicklisch-Franken, Hamish Mackenzie
-- License : GNU-GPL
--
-- Maintainer : <maintainer at leksah.org>
-- Stability : provisional
-- Portability : portable
--
-- | Module for the basiscs of composing GUIs from editors
--
-----------------------------------------------------------------------------------
module Graphics.UI.Editor.Basics (
-- * Types
Getter
, Setter
, Injector
, Extractor
, Applicator
, Editor
, emptyNotifier
, GUIEvent(..)
, GUIEventSelector(..)
, GtkRegFunc
, Notifier(..)
, GtkHandler
, Connection(..)
, Connections
, activateEvent
, propagateEvent
, allGUIEvents
, genericGUIEvents
, propagateAsChanged
) where
import Graphics.UI.Gtk
import Data.Unique
import Data.IORef
import Control.Monad
import Control.Monad.Trans (liftIO)
import Graphics.UI.Editor.Parameters
import Control.Event
import Data.Map (Map(..))
import qualified Data.Map as Map (delete,insert,lookup,empty)
import Data.Maybe (isJust,fromJust)
import Unsafe.Coerce (unsafeCoerce)
import Control.Arrow (first)
import MyMissing (allOf)
-- ---------------------------------------------------------------------
-- * Basic Types
--
--
-- | A type for getting a field of a record
--
type Getter alpha beta = alpha -> beta
--
-- | A type for setting the field of a record
--
type Setter alpha beta = beta -> alpha -> alpha
--
-- | A type for injecting a value into an editor
--
type Injector beta = beta -> IO ()
--
-- | A type for extracting a value from an editor
--
type Extractor beta = IO (Maybe beta)
--
-- | A type for the application of a value to be reflected in the GUI
--
type Applicator beta gamma = beta -> gamma ()
--
-- | A type to describe an editor.
-- alpha is the type of the individual field of the record
type Editor alpha = Parameters -> Notifier
-> IO(Widget, Injector alpha , Extractor alpha)
--
-- | A type for an event in the GUI
--
data GUIEvent = GUIEvent {
selector :: GUIEventSelector
, eventText :: String
, gtkReturn :: Bool -- ^ True means that the event has been completely handled,
-- gtk shoudn't do any further action about it (Often not
-- a good idea
}
instance Event GUIEvent GUIEventSelector where
getSelector = selector
data GUIEventSelector = FocusOut -- ^ generic, the widget looses the focus
| FocusIn -- ^ generic, the widget gets the focus
| ButtonPressed -- ^ generic, a mouse key has been pressed and released, while the widget has the focus
| KeyPressed -- ^ generic, a keyboard key has been pressed and released, while the widget has the focus
| Clicked -- ^ button specific, the button has been pressed
| MayHaveChanged -- ^ generic, no gui event, the contents of the widget may have changed
| ValidationError -- ^ validation of a contents has failed
deriving (Eq,Ord,Show,Enum,Bounded)
instance EventSelector GUIEventSelector
allGUIEvents :: [GUIEventSelector]
allGUIEvents = allOf
genericGUIEvents = [FocusOut,FocusIn,ButtonPressed,KeyPressed]
-- ------------------------------------------------------------
-- * Implementation of GUI event system
-- ------------------------------------------------------------
-- | A type for handling an IO event
-- Returning True: The event has been handles
-- Returning False: Handling should proceed
type GtkHandler = IO Bool
--
-- | A type for a function to register a gtk event
-- |
type GtkRegFunc = forall o . GObjectClass o => o -> GtkHandler -> IO (Connection)
--
-- | The widgets are the real event sources.
-- The GtkRegFunc is the function used to register the event.
-- The connectIds are set, when the event is activated, and
-- can be used to deactivate the event.
-- Or it is a propagated event and:
-- The Notifier List is a list of event sources, to which registrations
-- are propageted.
-- The last map is used to unregister propagated events properly
--
type GUIEventReg = ([Connection],
([Notifier], Map Unique [(Unique,Notifier)]))
--
-- | The event source in the gtk editor context
-- If the second argument is Left Handler the handler gets registered
-- If the second argument is Right Unique the handler will be removed
-- The returned unique value must be used for unregistering an event
newtype Notifier = Noti (IORef (Handlers GUIEvent IO GUIEventSelector,
Map GUIEventSelector GUIEventReg))
emptyNotifier :: IO Notifier
emptyNotifier = do
h <- newIORef (Map.empty,Map.empty)
let noti = Noti h
return noti
--
-- | Signal handlers for the different pane types
--
data Connection = forall alpha . GObjectClass alpha => ConnectC (ConnectId alpha)
type Connections = [Connection]
instance EventSource Notifier GUIEvent IO GUIEventSelector where
getHandlers (Noti pairRef) = do
(h,_) <- readIORef pairRef
return h
setHandlers (Noti pairRef) h = do
(_,r) <- readIORef pairRef
writeIORef pairRef (h,r)
myUnique _ = newUnique
canTriggerEvent _ _ = True
registerEvent o@(Noti pairRef) eventSel hand = do
(handlers, ger) <- readIORef pairRef
unique <- myUnique o
newGer <- case Map.lookup eventSel ger of
Nothing -> return ger
Just (_,([],um)) -> return ger
Just (cids,(notifiers,um)) -> do
lu <- mapM (\es -> registerEvent es eventSel hand)
notifiers
let jl = map (first fromJust)
$ filter (isJust.fst)
$ zip lu notifiers
let newUm = Map.insert unique jl um
return (Map.insert eventSel (cids,(notifiers,newUm)) ger)
let newHandlers = case eventSel `Map.lookup` handlers of
Nothing -> Map.insert eventSel
[(unique,hand)] handlers
Just l -> Map.insert eventSel
((unique,hand):l) handlers
writeIORef pairRef (newHandlers,newGer)
return (Just unique)
unregisterEvent o@(Noti pairRef) eventSel unique = do
(handlers, ger) <- readIORef pairRef
newGer <- case Map.lookup eventSel ger of
Nothing -> return ger
Just (cids,(notis,um)) ->
case unique `Map.lookup` um of
Nothing -> return ger
Just l -> do
mapM_ (\(u,es) -> unregisterEvent es eventSel u) l
let newUm = unique `Map.delete` um
return (Map.insert eventSel (cids,(notis,newUm)) ger)
let newHandlers = case eventSel `Map.lookup` handlers of
Nothing -> handlers
Just l -> case filter (\ (mu,_) -> mu /= unique) l of
[] -> Map.delete eventSel handlers
l -> Map.insert eventSel l handlers
writeIORef pairRef (newHandlers,newGer)
return ()
--
-- | Propagate the event with the selector from notifier to eventSource
--
propagateEvent :: Notifier -> [Notifier] -> GUIEventSelector -> IO ()
propagateEvent (Noti pairRef) eventSources eventSel = do
(handlers,ger) <- readIORef pairRef
let newGer = case Map.lookup eventSel ger of
Nothing -> Map.insert eventSel
([],(eventSources,Map.empty)) ger
Just (w,(notiList,unregMap)) -> Map.insert eventSel
(w,(eventSources ++ notiList,unregMap)) ger
--now propagate already registered events
newGer2 <- case eventSel `Map.lookup` handlers of
Nothing -> return newGer
Just hl -> foldM (repropagate eventSel) newGer hl
writeIORef pairRef (handlers,newGer)
where
repropagate :: GUIEventSelector
-> Map GUIEventSelector GUIEventReg
-> (Unique, GUIEvent -> IO GUIEvent)
-> IO (Map GUIEventSelector GUIEventReg)
repropagate eventSet ger (unique,hand) =
case Map.lookup eventSel ger of
Just (cids,(notifiers,um))
-> do
lu <- mapM (\es -> registerEvent es eventSel hand)
notifiers
let jl = map (first fromJust)
$ filter (isJust.fst)
$ zip lu notifiers
let newUm = Map.insert unique jl um
return (Map.insert eventSel (cids,(notifiers,newUm)) ger)
_ -> error "Basics>>propagateEvent: impossible case"
--
-- | Activate the event after the event has been declared and the
-- widget has been constructed
--
activateEvent
:: GObjectClass o =>
o
-> Notifier
-> Maybe (o -> IO Bool -> IO Connection)
-> GUIEventSelector
-> IO ()
activateEvent widget (Noti pairRef) mbRegisterFunc eventSel = do
let registerFunc = case mbRegisterFunc of
Just f -> f
Nothing -> getStandardRegFunction eventSel
cid <- registerFunc widget (do
(hi,_) <- readIORef pairRef
case Map.lookup eventSel hi of
Nothing -> return False
Just [] -> return False
Just handlers -> do
name <- if (widget `isA` gTypeWidget)
then widgetGetName (castToWidget widget)
else return "no widget - no name"
eventList <- mapM (\f -> do
let ev = GUIEvent eventSel "" False
f ev)
(map snd handlers)
let boolList = map gtkReturn eventList
return (foldr (&&) True boolList))
(handerls,ger) <- readIORef pairRef
let newGer = case Map.lookup eventSel ger of
Nothing -> Map.insert eventSel ([cid],([],Map.empty))
ger
Just (cids,prop) ->
Map.insert eventSel (cid:cids,prop) ger
writeIORef pairRef (handerls,newGer)
--
-- | A convinence method for not repeating this over and over again
--
getStandardRegFunction :: GUIEventSelector -> GtkRegFunc
getStandardRegFunction FocusOut = \w h -> liftM ConnectC $ on (castToWidget w) focusOutEvent $ liftIO h
getStandardRegFunction FocusIn = \w h -> liftM ConnectC $ on (castToWidget w) focusInEvent $ liftIO h
getStandardRegFunction ButtonPressed = \w h -> liftM ConnectC $ after (castToWidget w) buttonReleaseEvent $ liftIO h
getStandardRegFunction KeyPressed = \w h -> liftM ConnectC $ after (castToWidget w) keyReleaseEvent $ liftIO h
getStandardRegFunction Clicked = \w h -> liftM ConnectC $ on (castToButton w) buttonActivated $ liftIO h >> return ()
getStandardRegFunction _ = error "Basic>>getStandardRegFunction: no original GUI event"
registerEvents :: EventSource alpha beta gamma delta => alpha -> [delta] -> (beta -> gamma beta) -> gamma [Maybe Unique]
registerEvents notifier selectors handler =
mapM (\ s -> registerEvent notifier s handler) selectors
propagateAsChanged
:: (EventSource alpha GUIEvent m GUIEventSelector) =>
alpha -> [GUIEventSelector] -> m ()
propagateAsChanged notifier selectors =
mapM_ (\s -> registerEvent notifier s
(\ e -> triggerEvent notifier e{selector = MayHaveChanged})) selectors