@@ -4,18 +4,70 @@ Description: Basic set of widgets and building blocks for reflex-vty application
5{-# Language UndecidableInstances #-}
5{-# Language UndecidableInstances #-}
7−module Reflex.Vty.Widget where
7+module Reflex.Vty.Widget
14+ , mainWidgetWithHandle
18+ , HasVtyWidgetCtx(..)
28+ , ScrollDirection(..)
9import Control.Applicative (liftA2)
59import Control.Applicative (liftA2)
10import Control.Monad.Fix (MonadFix)
60import Control.Monad.Fix (MonadFix)
11import Control.Monad.IO.Class (MonadIO)
61import Control.Monad.IO.Class (MonadIO)
12−import Control.Monad.Morph
13import Control.Monad.NodeId
62import Control.Monad.NodeId
14−import Control.Monad.Reader (ReaderT, ask, local, runReaderT)
63+import Control.Monad.Reader (ReaderT, ask, asks, local, runReaderT)
15−import Control.Monad.Ref
16import Control.Monad.Trans (MonadTrans, lift)
64import Control.Monad.Trans (MonadTrans, lift)
65+import Data.Default (Default(..))
17import Data.Set (Set)
66import Data.Set (Set)
18import qualified Data.Set as Set
67import qualified Data.Set as Set
68+import Data.Text (Text)
69+import qualified Data.Text as T
70+import qualified Data.Text.Zipper as TZ
19import Graphics.Vty (Image)
71import Graphics.Vty (Image)
20import qualified Graphics.Vty as V
72import qualified Graphics.Vty as V
21import Reflex
73import Reflex
@@ -23,20 +75,85 @@ import Reflex.Class ()
23import Reflex.Host.Class (MonadReflexCreateTrigger)
75import Reflex.Host.Class (MonadReflexCreateTrigger)
24import Reflex.Vty.Host
76import Reflex.Vty.Host
26−-- * Running a vty application
78+-- | The context within which a 'VtyWidget' runs
79+data VtyWidgetCtx t = VtyWidgetCtx
80+ { _vtyWidgetCtx_width :: Dynamic t Int
81+ -- ^ The width of the region allocated to the widget.
82+ , _vtyWidgetCtx_height :: Dynamic t Int
83+ -- ^ The height of the region allocated to the widget.
84+ , _vtyWidgetCtx_focus :: Dynamic t Bool
85+ -- ^ Whether the widget should behave as if it has focus for keyboard input.
88+-- | The output of a 'VtyWidget'
89+data VtyWidgetOut t = VtyWidgetOut
90+ { _vtyWidgetOut_shutdown :: Event t ()
93+instance (Adjustable t m, MonadHold t m, Reflex t) => Adjustable t (VtyWidget t m) where
94+ runWithReplace a0 a' = VtyWidget $ runWithReplace (unVtyWidget a0) $ fmap unVtyWidget a'
95+ traverseIntMapWithKeyWithAdjust f dm0 dm' = VtyWidget $
96+ traverseIntMapWithKeyWithAdjust (\k v -> unVtyWidget (f k v)) dm0 dm'
97+ traverseDMapWithKeyWithAdjust f dm0 dm' = VtyWidget $ do
98+ traverseDMapWithKeyWithAdjust (\k v -> unVtyWidget (f k v)) dm0 dm'
99+ traverseDMapWithKeyWithAdjustWithMove f dm0 dm' = VtyWidget $ do
100+ traverseDMapWithKeyWithAdjustWithMove (\k v -> unVtyWidget (f k v)) dm0 dm'
102+-- | A widget that can read its context and produce image output
103+newtype VtyWidget t m a = VtyWidget
104+ { unVtyWidget :: BehaviorWriterT t [Image]
105+ (ReaderT (VtyWidgetCtx t)
106+ (ReaderT (Event t VtyEvent) m)) a
118+ , MonadReflexCreateTrigger t
122+deriving instance PerformEvent t m => PerformEvent t (VtyWidget t m)
123+instance MonadTrans (VtyWidget t) where
124+ lift f = VtyWidget $ lift $ lift $ lift f
126+instance MonadNodeId m => MonadNodeId (VtyWidget t m) where
127+ getNextNodeId = VtyWidget $ do
128+ lift $ lift getNextNodeId
130+-- | A reader-like class for the vty widget context. Allows actions to be run in a sub-context.
131+class HasVtyWidgetCtx t m | m -> t where
132+ askCtx :: m (VtyWidgetCtx t)
133+ default askCtx :: (f m' ~ m, Monad m', MonadTrans f, HasVtyWidgetCtx t m') => m (VtyWidgetCtx t)
134+ askCtx = lift askCtx
135+ localCtx :: (VtyWidgetCtx t -> VtyWidgetCtx t) -> (Behavior t [Image] -> Behavior t [Image]) -> m a -> m a
137+instance (Monad m, Reflex t) => HasVtyWidgetCtx t (VtyWidget t m) where
138+ askCtx = VtyWidget $ lift ask
139+ localCtx f g (VtyWidget x) = VtyWidget $ do
140+ (a, images) :: (a, Behavior t [Image]) <- lift $ local f $ runBehaviorWriterT x
141+ tellImages $ g images
144+-- | Runs a 'VtyWidget' with a given context
146+ :: (Reflex t, MonadNodeId m)
150+ -> m (a, Behavior t [Image])
151+runVtyWidget e ctx w = runReaderT (runReaderT (runBehaviorWriterT (unVtyWidget w)) ctx) e
28−-- | Sets up the top-level context for a vty widget and runs it with that context
153+-- | Sets up the top-level context for a 'VtyWidget' and runs it with that context
29mainWidgetWithHandle
154mainWidgetWithHandle
32− ( MonadVtyApp t m
156+ -> (forall t m. (MonadVtyApp t m, MonadNodeId m) => VtyWidget t m (Event t ()))
35− , HasDisplayRegion t m
41mainWidgetWithHandle vty child =
158mainWidgetWithHandle vty child =
42 runVtyAppWithHandle vty $ \dr0 inp -> do
159 runVtyAppWithHandle vty $ \dr0 inp -> do
@@ -46,178 +163,89 @@ mainWidgetWithHandle vty child =
46 let inp' = fforMaybe inp $ \case
163 let inp' = fforMaybe inp $ \case
47 V.EvResize {} -> Nothing
164 V.EvResize {} -> Nothing
48 x -> Just x
165 x -> Just x
49− (shutdown, images) <- runThemeReader (constant V.defAttr) $
166+ let ctx = VtyWidgetCtx
50− runFocusReader (pure True) $
167+ { _vtyWidgetCtx_width = fmap fst size
51− runDisplayRegion (fmap (\(w, h) -> Region 0 0 w h) size) $
168+ , _vtyWidgetCtx_height = fmap snd size
52− runImageWriter $
169+ , _vtyWidgetCtx_focus = constDyn True
54− runInput inp' $ do
171+ (shutdown, images) <- runNodeIdT $ runVtyWidget inp' ctx $ do
55− tellImages . ffor (current size) $ \(w, h) -> [V.charFill V.defAttr ' ' w h]
172+ tellImages . ffor (current size) $ \(w, h) -> [V.charFill V.defAttr ' ' w h]
57 return $ VtyResult
174 return $ VtyResult
58 { _vtyResult_picture = fmap (V.picForLayers . reverse) images
175 { _vtyResult_picture = fmap (V.picForLayers . reverse) images
59 , _vtyResult_shutdown = shutdown
176 , _vtyResult_shutdown = shutdown
62−-- | The output of a vty widget
63−data VtyWidgetOut t = VtyWidgetOut
64− { _vtyWidgetOut_shutdown :: Event t ()
67-- | Like 'mainWidgetWithHandle', but uses a default vty configuration
179-- | Like 'mainWidgetWithHandle', but uses a default vty configuration
68mainWidget
180mainWidget
70− ( MonadVtyApp t m
181+ :: (forall t m. (MonadVtyApp t m, MonadNodeId m) => VtyWidget t m (Event t ()))
73− , HasDisplayRegion t m
79mainWidget child = do
183mainWidget child = do
80 vty <- getDefaultVty
184 vty <- getDefaultVty
81 mainWidgetWithHandle vty child
185 mainWidgetWithHandle vty child
83−-- * Input Events
187+-- | A class for things that know their own display size dimensions
188+class (Reflex t, Monad m) => HasDisplaySize t m | m -> t where
189+ -- | Retrieve the display width (columns)
190+ displayWidth :: m (Dynamic t Int)
191+ default displayWidth :: (f m' ~ m, MonadTrans f, HasDisplaySize t m') => m (Dynamic t Int)
192+ displayWidth = lift displayWidth
193+ -- | Retrieve the display height (rows)
194+ displayHeight :: m (Dynamic t Int)
195+ default displayHeight :: (f m' ~ m, MonadTrans f, HasDisplaySize t m') => m (Dynamic t Int)
196+ displayHeight = lift displayHeight
198+instance (Reflex t, Monad m) => HasDisplaySize t (VtyWidget t m) where
199+ displayWidth = VtyWidget . lift $ asks _vtyWidgetCtx_width
200+ displayHeight = VtyWidget . lift $ asks _vtyWidgetCtx_height
202+instance HasDisplaySize t m => HasDisplaySize t (ReaderT x m)
203+instance HasDisplaySize t m => HasDisplaySize t (BehaviorWriterT t x m)
204+instance HasDisplaySize t m => HasDisplaySize t (DynamicWriterT t x m)
205+instance HasDisplaySize t m => HasDisplaySize t (EventWriterT t x m)
206+instance HasDisplaySize t m => HasDisplaySize t (NodeIdT m)
85-- | A class for things that can receive vty events as input
208-- | A class for things that can receive vty events as input
86−class HasInput t m | m -> t where
209+class HasVtyInput t m | m -> t where
87 input :: m (Event t VtyEvent)
210 input :: m (Event t VtyEvent)
88− default input :: (f m' ~ m, Monad m', MonadTrans f, HasInput t m') => m (Event t VtyEvent)
211+ default input :: (f m' ~ m, Monad m', MonadTrans f, HasVtyInput t m') => m (Event t VtyEvent)
89 input = lift input
212 input = lift input
90 -- | User input events that the widget's parent chooses to share. These will generally
213 -- | User input events that the widget's parent chooses to share. These will generally
91 -- be filtered for relevance.
214 -- be filtered for relevance.
92 localInput :: (Event t VtyEvent -> Event t VtyEvent) -> m a -> m a
215 localInput :: (Event t VtyEvent -> Event t VtyEvent) -> m a -> m a
93− default localInput :: (f m' ~ m, Monad m', MFunctor f, HasInput t m') => (Event t VtyEvent -> Event t VtyEvent) -> m a -> m a
94− localInput f = hoist (localInput f)
96−instance (Reflex t, Monad m) => HasInput t (Input t m) where
98− localInput f (Input m) = Input $ local f m
100−-- | A widget that can receive input events. See 'Graphics.Vty.Event'
101−newtype Input t m a = Input
102− { unInput :: ReaderT (Event t VtyEvent) m a
114−instance (Adjustable t m, MonadHold t m, Reflex t) => Adjustable t (Input t m) where
115− runWithReplace a0 a' = Input $ runWithReplace (unInput a0) $ fmap unInput a'
116− traverseIntMapWithKeyWithAdjust f dm0 dm' = Input $
117− traverseIntMapWithKeyWithAdjust (\k v -> unInput (f k v)) dm0 dm'
118− traverseDMapWithKeyWithAdjust f dm0 dm' = Input $ do
119− traverseDMapWithKeyWithAdjust (\k v -> unInput (f k v)) dm0 dm'
120− traverseDMapWithKeyWithAdjustWithMove f dm0 dm' = Input $ do
121− traverseDMapWithKeyWithAdjustWithMove (\k v -> unInput (f k v)) dm0 dm'
123−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (Input t m)
124−deriving instance NotReady t m => NotReady t (Input t m)
125−deriving instance PerformEvent t m => PerformEvent t (Input t m)
126−deriving instance PostBuild t m => PostBuild t (Input t m)
127−deriving instance TriggerEvent t m => TriggerEvent t (Input t m)
128−instance HasImageWriter t m => HasImageWriter t (Input t m)
129−instance HasDisplayRegion t m => HasDisplayRegion t (Input t m)
130−instance HasFocusReader t m => HasFocusReader t (Input t m)
132−instance MonadTrans (Input t) where
133− lift f = Input $ lift f
135−instance MFunctor (Input t) where
136− hoist f = Input . hoist f . unInput
138−instance MonadNodeId m => MonadNodeId (Input t m)
140−-- | Runs an 'Input' with a given context
146−runInput e w = runReaderT (unInput w) e
148−-- ** Filtering input
150−-- | Type synonym for a key and modifier combination
151−type KeyCombo = (V.Key, [V.Modifier])
153−-- | Emits an event that fires on a particular key press (without modifiers)
154−key :: (Monad m, Reflex t, HasInput t m) => V.Key -> m (Event t KeyCombo)
155−key = keyCombos . Set.singleton . (,[])
157−-- | Emits an event that fires on particular key presses (without modifiers)
158−keys :: (Monad m, Reflex t, HasInput t m) => [V.Key] -> m (Event t KeyCombo)
159−keys = keyCombos . Set.fromList . fmap (,[])
161−-- | Emit an event that fires whenever the provided key combination occurs
163− :: (Reflex t, Monad m, HasInput t m)
165− -> m (Event t KeyCombo)
166−keyCombo = keyCombos . Set.singleton
168−-- | Emit an event that fires whenever any of the provided key combinations occur
170− :: (Reflex t, Monad m, HasInput t m)
172− -> m (Event t KeyCombo)
175− return $ fforMaybe i $ \case
176− V.EvKey k m -> if Set.member (k, m) ks
181-- | Filter the keyboard input that a child widget may receive
217-- | Filter the keyboard input that a child widget may receive
182−filterKeys :: (Reflex t, HasInput t m) => (KeyCombo -> Bool) -> m a -> m a
218+filterKeys :: (Reflex t, HasVtyInput t m) => (KeyCombo -> Bool) -> m a -> m a
183filterKeys f x = localInput (ffilter (\case
219filterKeys f x = localInput (ffilter (\case
184 V.EvKey k mods -> f (k, mods)
220 V.EvKey k mods -> f (k, mods)
185 _ -> True)) x
221 _ -> True)) x
187−-- | Filter mouse input events based on whether they target a particular region
223+instance (Reflex t, Monad m) => HasVtyInput t (VtyWidget t m) where
188−-- and translate them to the internal coordinate system of that region.
224+ input = VtyWidget . lift $ lift $ ask
189−--
225+ localInput f (VtyWidget m) = VtyWidget $ do
190−-- NB: Non-mouse events are passed through unfiltered and unchanged
226+ ctx <- ask
191−mouseInRegion :: Region -> VtyEvent -> Maybe VtyEvent
227+ (a, images) <- lift $ lift $ local f $ runReaderT (runBehaviorWriterT m) ctx
192−mouseInRegion (Region l t w h) e = case e of
228+ tellImages images
193− V.EvMouseDown x y btn m -> mouse (\u v -> V.EvMouseDown u v btn m) x y
229+ pure a
194− V.EvMouseUp x y btn -> mouse (\u v -> V.EvMouseUp u v btn) x y
230+
195− _ -> Just e
231+-- | A class for things that can dynamically gain and lose focus
196− where
232+class HasFocus t m | m -> t where
197− mouse con x y
233+ focus :: m (Dynamic t Bool)
198− | or [ x < l
234+ default focus :: (f m' ~ m, Monad m', MonadTrans f, HasFocus t m') => m (Dynamic t Bool)
199− , y < t
235+ focus = lift focus
201− , y >= t + h ] = Nothing
237+instance (Reflex t, Monad m) => HasFocus t (VtyWidget t m) where
202− | otherwise =
238+ focus = VtyWidget . lift $ asks _vtyWidgetCtx_focus
203− Just (con (x - l) (y - t))
239+
204−
240+-- | A class for widgets that can produce images to draw to the display
205−-- | Filter mouse input outside the current display region and
241+class (Reflex t, Monad m) => ImageWriter t m | m -> t where
206−-- all input if the region is not focused
242+ -- | Send images upstream for rendering
207−inputInFocusedRegion
243+ tellImages :: Behavior t [Image] -> m ()
208− :: (HasDisplayRegion t m, HasFocusReader t m, HasInput t m)
244+ default tellImages :: (f m' ~ m, Monad m', MonadTrans f, ImageWriter t m') => Behavior t [Image] -> m ()
209− => m (Event t VtyEvent)
245+ tellImages = lift . tellImages
210−inputInFocusedRegion = do
212− reg <- current <$> askRegion
213− foc <- current <$> focus
214− pure $ fmapMaybe id $ attachWith filterInput ((,) <$> reg <*> foc) inp
216− filterInput (r, f) = \case
217− V.EvKey {} | not f -> Nothing
218− x -> mouseInRegion r x
220−-- * Getting and setting the display region
247+instance (Monad m, Reflex t) => ImageWriter t (BehaviorWriterT t [Image] m) where
248+ tellImages = tellBehavior
222-- | A chunk of the display area
250-- | A chunk of the display area
223data Region = Region
251data Region = Region
@@ -228,293 +256,14 @@ data Region = Region
229 deriving (Show, Read, Eq, Ord)
257 deriving (Show, Read, Eq, Ord)
231−-- | A region that occupies no space.
233−nilRegion = Region 0 0 0 0
235-- | The width and height of a 'Region'
259-- | The width and height of a 'Region'
236regionSize :: Region -> (Int, Int)
260regionSize :: Region -> (Int, Int)
237regionSize (Region _ _ w h) = (w, h)
261regionSize (Region _ _ w h) = (w, h)
239-- | Produces an 'Image' that fills a region with space characters
263-- | Produces an 'Image' that fills a region with space characters
240−regionBlankImage :: V.Attr -> Region -> Image
264+regionBlankImage :: Region -> Image
241−regionBlankImage attr r@(Region _ _ width height) =
265+regionBlankImage r@(Region _ _ width height) =
242− withinImage r $ V.charFill attr ' ' width height
266+ withinImage r $ V.charFill V.defAttr ' ' width height
244−-- | A class for things that know their own display size dimensions
245−class (Reflex t, Monad m) => HasDisplayRegion t m | m -> t where
246− -- | Retrieve the display region
247− askRegion :: m (Dynamic t Region)
248− default askRegion :: (f m' ~ m, MonadTrans f, HasDisplayRegion t m') => m (Dynamic t Region)
249− askRegion = lift askRegion
250− -- | Run an action in a local region, by applying a transformation to the region
251− localRegion :: (Dynamic t Region -> Dynamic t Region) -> m a -> m a
252− default localRegion :: (f m' ~ m, Monad m', MFunctor f, HasDisplayRegion t m') => (Dynamic t Region -> Dynamic t Region) -> m a -> m a
253− localRegion f = hoist (localRegion f)
255−-- | Retrieve the display width
256−displayWidth :: HasDisplayRegion t m => m (Dynamic t Int)
257−displayWidth = fmap _region_width <$> askRegion
259−-- | Retrieve the display height
260−displayHeight :: HasDisplayRegion t m => m (Dynamic t Int)
261−displayHeight = fmap _region_height <$> askRegion
263−instance HasDisplayRegion t m => HasDisplayRegion t (ReaderT x m)
264−instance HasDisplayRegion t m => HasDisplayRegion t (BehaviorWriterT t x m)
265−instance HasDisplayRegion t m => HasDisplayRegion t (DynamicWriterT t x m)
266−instance HasDisplayRegion t m => HasDisplayRegion t (EventWriterT t x m)
267−instance HasDisplayRegion t m => HasDisplayRegion t (NodeIdT m)
269−-- | A widget that has access to a particular region of the vty display
270−newtype DisplayRegion t m a = DisplayRegion
271− { unDisplayRegion :: ReaderT (Dynamic t Region) m a }
283−instance (Monad m, Reflex t) => HasDisplayRegion t (DisplayRegion t m) where
284− askRegion = DisplayRegion ask
285− localRegion f = DisplayRegion . local f . unDisplayRegion
287−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (DisplayRegion t m)
288−deriving instance NotReady t m => NotReady t (DisplayRegion t m)
289−deriving instance PerformEvent t m => PerformEvent t (DisplayRegion t m)
290−deriving instance PostBuild t m => PostBuild t (DisplayRegion t m)
291−deriving instance TriggerEvent t m => TriggerEvent t (DisplayRegion t m)
292−instance HasImageWriter t m => HasImageWriter t (DisplayRegion t m)
293−instance HasFocusReader t m => HasFocusReader t (DisplayRegion t m)
295−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (DisplayRegion t m) where
296− runWithReplace (DisplayRegion a) e = DisplayRegion $ runWithReplace a $ fmap unDisplayRegion e
297− traverseIntMapWithKeyWithAdjust f m e = DisplayRegion $ traverseIntMapWithKeyWithAdjust (\k v -> unDisplayRegion $ f k v) m e
298− traverseDMapWithKeyWithAdjust f m e = DisplayRegion $ traverseDMapWithKeyWithAdjust (\k v -> unDisplayRegion $ f k v) m e
299− traverseDMapWithKeyWithAdjustWithMove f m e = DisplayRegion $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unDisplayRegion $ f k v) m e
301−instance MonadTrans (DisplayRegion t) where
302− lift = DisplayRegion . lift
304−instance MFunctor (DisplayRegion t) where
305− hoist f = DisplayRegion . hoist f . unDisplayRegion
307−instance MonadNodeId m => MonadNodeId (DisplayRegion t m)
309−-- | Run a 'DisplayRegion' action with a given 'Region'
311− :: (Reflex t, Monad m)
313− -> DisplayRegion t m a
315−runDisplayRegion r = flip runReaderT r . unDisplayRegion
317−-- * Getting focus state
319−-- | A class for things that can dynamically gain and lose focus
320−class (Reflex t, Monad m) => HasFocusReader t m | m -> t where
321− focus :: m (Dynamic t Bool)
322− default focus :: (f m' ~ m, Monad m', MonadTrans f, HasFocusReader t m') => m (Dynamic t Bool)
324− localFocus :: (Dynamic t Bool -> Dynamic t Bool) -> m a -> m a
325− default localFocus :: (f m' ~ m, Monad m', MFunctor f, HasFocusReader t m') => (Dynamic t Bool -> Dynamic t Bool) -> m a -> m a
326− localFocus f = hoist (localFocus f)
328−instance HasFocusReader t m => HasFocusReader t (ReaderT x m)
329−instance HasFocusReader t m => HasFocusReader t (BehaviorWriterT t x m)
330−instance HasFocusReader t m => HasFocusReader t (DynamicWriterT t x m)
331−instance HasFocusReader t m => HasFocusReader t (EventWriterT t x m)
332−instance HasFocusReader t m => HasFocusReader t (NodeIdT m)
334−-- | A widget that has access to information about whether it is focused
335−newtype FocusReader t m a = FocusReader
336− { unFocusReader :: ReaderT (Dynamic t Bool) m a }
348−instance (Monad m, Reflex t) => HasFocusReader t (FocusReader t m) where
349− focus = FocusReader ask
350− localFocus f = FocusReader . local f . unFocusReader
352−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (FocusReader t m)
353−deriving instance NotReady t m => NotReady t (FocusReader t m)
354−deriving instance PerformEvent t m => PerformEvent t (FocusReader t m)
355−deriving instance PostBuild t m => PostBuild t (FocusReader t m)
356−deriving instance TriggerEvent t m => TriggerEvent t (FocusReader t m)
357−instance HasImageWriter t m => HasImageWriter t (FocusReader t m)
359−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (FocusReader t m) where
360− runWithReplace (FocusReader a) e = FocusReader $ runWithReplace a $ fmap unFocusReader e
361− traverseIntMapWithKeyWithAdjust f m e = FocusReader $ traverseIntMapWithKeyWithAdjust (\k v -> unFocusReader $ f k v) m e
362− traverseDMapWithKeyWithAdjust f m e = FocusReader $ traverseDMapWithKeyWithAdjust (\k v -> unFocusReader $ f k v) m e
363− traverseDMapWithKeyWithAdjustWithMove f m e = FocusReader $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unFocusReader $ f k v) m e
365−instance MonadTrans (FocusReader t) where
366− lift = FocusReader . lift
368−instance MFunctor (FocusReader t) where
369− hoist f = FocusReader . hoist f . unFocusReader
371−instance MonadNodeId m => MonadNodeId (FocusReader t m)
373−-- | Run a 'FocusReader' action with the given focus value
375− :: (Reflex t, Monad m)
377− -> FocusReader t m a
379−runFocusReader b = flip runReaderT b . unFocusReader
383−-- | A class for widgets that can produce images to draw to the display
384−class (Reflex t, Monad m) => HasImageWriter t m | m -> t where
385− -- | Send images upstream for rendering
386− tellImages :: Behavior t [Image] -> m ()
387− default tellImages :: (f m' ~ m, Monad m', MonadTrans f, HasImageWriter t m') => Behavior t [Image] -> m ()
388− tellImages = lift . tellImages
389− -- | Apply a transformation to the images produced by the child actions
390− mapImages :: (Behavior t [Image] -> Behavior t [Image]) -> m a -> m a
391− default mapImages :: (f m' ~ m, Monad m', MFunctor f, HasImageWriter t m') => (Behavior t [Image] -> Behavior t [Image]) -> m a -> m a
392− mapImages f = hoist (mapImages f)
394−-- | A widget that can produce images to draw onto the display
395−newtype ImageWriter t m a = ImageWriter
396− { unImageWriter :: BehaviorWriterT t [Image] m a }
405− , MonadReflexCreateTrigger t
413−instance MonadTrans (ImageWriter t) where
414− lift = ImageWriter . lift
416−instance MFunctor (ImageWriter t) where
417− hoist f = ImageWriter . (hoist f) . unImageWriter
419−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (ImageWriter t m) where
420− runWithReplace (ImageWriter a) e = ImageWriter $ runWithReplace a $ fmap unImageWriter e
421− traverseIntMapWithKeyWithAdjust f m e = ImageWriter $ traverseIntMapWithKeyWithAdjust (\k v -> unImageWriter $ f k v) m e
422− traverseDMapWithKeyWithAdjust f m e = ImageWriter $ traverseDMapWithKeyWithAdjust (\k v -> unImageWriter $ f k v) m e
423− traverseDMapWithKeyWithAdjustWithMove f m e = ImageWriter $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unImageWriter $ f k v) m e
425−instance HasImageWriter t m => HasImageWriter t (ReaderT x m)
426−instance HasImageWriter t m => HasImageWriter t (BehaviorWriterT t x m)
427−instance HasImageWriter t m => HasImageWriter t (DynamicWriterT t x m)
428−instance HasImageWriter t m => HasImageWriter t (EventWriterT t x m)
429−instance HasImageWriter t m => HasImageWriter t (NodeIdT m)
431−instance (Monad m, Reflex t) => HasImageWriter t (ImageWriter t m) where
432− tellImages = ImageWriter . tellBehavior
433− mapImages f (ImageWriter x) = ImageWriter $ do
434− (a, images) <- lift $ runBehaviorWriterT x
435− tellBehavior $ f images
438−instance HasDisplayRegion t m => HasDisplayRegion t (ImageWriter t m)
439−instance HasFocusReader t m => HasFocusReader t (ImageWriter t m)
441−-- | Run a widget that can produce images
443− :: (Reflex t, Monad m)
444− => ImageWriter t m a
445− -> m (a, Behavior t [Image])
446−runImageWriter = runBehaviorWriterT . unImageWriter
450−-- | A class for things that can be visually styled
451−class (Reflex t, Monad m) => HasTheme t m | m -> t where
452− theme :: m (Behavior t V.Attr)
453− default theme :: (f m' ~ m, Monad m', MonadTrans f, HasTheme t m') => m (Behavior t V.Attr)
455− localTheme :: (Behavior t V.Attr -> Behavior t V.Attr) -> m a -> m a
456− default localTheme :: (f m' ~ m, Monad m', MFunctor f, HasTheme t m') => (Behavior t V.Attr -> Behavior t V.Attr) -> m a -> m a
457− localTheme f = hoist (localTheme f)
459−instance HasTheme t m => HasTheme t (ReaderT x m)
460−instance HasTheme t m => HasTheme t (BehaviorWriterT t x m)
461−instance HasTheme t m => HasTheme t (DynamicWriterT t x m)
462−instance HasTheme t m => HasTheme t (EventWriterT t x m)
463−instance HasTheme t m => HasTheme t (NodeIdT m)
464−instance HasTheme t m => HasTheme t (Input t m)
465−instance HasTheme t m => HasTheme t (ImageWriter t m)
466−instance HasTheme t m => HasTheme t (DisplayRegion t m)
467−instance HasTheme t m => HasTheme t (FocusReader t m)
469−-- | A widget that has access to theme information
470−newtype ThemeReader t m a = ThemeReader
471− { unThemeReader :: ReaderT (Behavior t V.Attr) m a }
483−instance (Monad m, Reflex t) => HasTheme t (ThemeReader t m) where
484− theme = ThemeReader ask
485− localTheme f = ThemeReader . local f . unThemeReader
487−deriving instance MonadReflexCreateTrigger t m => MonadReflexCreateTrigger t (ThemeReader t m)
488−deriving instance NotReady t m => NotReady t (ThemeReader t m)
489−deriving instance PerformEvent t m => PerformEvent t (ThemeReader t m)
490−deriving instance PostBuild t m => PostBuild t (ThemeReader t m)
491−deriving instance TriggerEvent t m => TriggerEvent t (ThemeReader t m)
492−instance HasImageWriter t m => HasImageWriter t (ThemeReader t m)
494−instance (Adjustable t m, MonadFix m, MonadHold t m) => Adjustable t (ThemeReader t m) where
495− runWithReplace (ThemeReader a) e = ThemeReader $ runWithReplace a $ fmap unThemeReader e
496− traverseIntMapWithKeyWithAdjust f m e = ThemeReader $ traverseIntMapWithKeyWithAdjust (\k v -> unThemeReader $ f k v) m e
497− traverseDMapWithKeyWithAdjust f m e = ThemeReader $ traverseDMapWithKeyWithAdjust (\k v -> unThemeReader $ f k v) m e
498− traverseDMapWithKeyWithAdjustWithMove f m e = ThemeReader $ traverseDMapWithKeyWithAdjustWithMove (\k v -> unThemeReader $ f k v) m e
500−instance MonadTrans (ThemeReader t) where
501− lift = ThemeReader . lift
503−instance MFunctor (ThemeReader t) where
504− hoist f = ThemeReader . hoist f . unThemeReader
506−instance MonadNodeId m => MonadNodeId (ThemeReader t m)
508−-- | Run a 'ThemeReader' action with the given focus value
510− :: (Reflex t, Monad m)
511− => Behavior t V.Attr
512− -> ThemeReader t m a
514−runThemeReader b = flip runReaderT b . unThemeReader
517−-- ** Manipulating images
519-- | Translates and crops an 'Image' so that it is contained by
268-- | Translates and crops an 'Image' so that it is contained by
520-- the given 'Region'.
269-- the given 'Region'.
@@ -526,17 +275,7 @@ withinImage (Region left top width height)
526 | width < 0 || height < 0 = withinImage (Region left top 0 0)
275 | width < 0 || height < 0 = withinImage (Region left top 0 0)
527 | otherwise = V.translate left top . V.crop width height
276 | otherwise = V.translate left top . V.crop width height
529−-- | Crop a behavior of images to a behavior of regions. See 'withinImage'.
532− => Behavior t Region
533− -> Behavior t [Image]
534− -> Behavior t [Image]
535−imagesInRegion reg = liftA2 (\r is -> map (withinImage r) is) reg
537−-- * Running sub-widgets
539−-- | Low-level widget combinator that runs a child widget within
278+-- | Low-level widget combinator that runs a child 'VtyWidget' within
540-- a given region and context. This widget filters and modifies the input
279-- a given region and context. This widget filters and modifies the input
541-- that the child widget receives such that:
280-- that the child widget receives such that:
542-- * unfocused widgets receive no key events
281-- * unfocused widgets receive no key events
@@ -544,17 +283,433 @@ imagesInRegion reg = liftA2 (\r is -> map (withinImage r) is) reg
544-- * mouse inputs inside the region have their coordinates translated such
283-- * mouse inputs inside the region have their coordinates translated such
545-- that (0,0) is the top-left corner of the region
284-- that (0,0) is the top-left corner of the region
547− :: (Reflex t, Monad m, HasInput t m, HasImageWriter t m, HasDisplayRegion t m, HasFocusReader t m)
286+ :: (Reflex t, Monad m, MonadNodeId m, HasVtyWidgetCtx t m, HasVtyInput t m)
548 => Dynamic t Region
287 => Dynamic t Region
549 -> Dynamic t Bool -- ^ Whether the widget should be focused when the parent is.
288 -> Dynamic t Bool -- ^ Whether the widget should be focused when the parent is.
552−pane dr foc child = localRegion (const dr) $
291+pane dr foc child = do
553− mapImages (imagesInRegion $ current dr) $
292+ let reg = current dr
554− localFocus (const foc) $
293+ let subContext ctx = VtyWidgetCtx
555− inputInFocusedRegion >>= \e -> localInput (const e) child
294+ { _vtyWidgetCtx_focus = liftA2 (&&) (_vtyWidgetCtx_focus ctx) foc
295+ , _vtyWidgetCtx_width = _region_width <$> dr
296+ , _vtyWidgetCtx_height = _region_height <$> dr
298+ inputFilter = fmapMaybe id .
299+ attachWith (\(r,f) e -> filterInput r f e)
300+ (liftA2 (,) reg (current foc))
301+ let imagesWithinRegion images = liftA2 (\is r -> map (withinImage r) is) images reg
302+ localInput inputFilter $ localCtx subContext imagesWithinRegion child
304+ filterInput :: Region -> Bool -> VtyEvent -> Maybe VtyEvent
305+ filterInput (Region l t w h) focused e = case e of
306+ V.EvKey _ _ | not focused -> Nothing
307+ V.EvMouseDown x y btn m -> mouse (\u v -> V.EvMouseDown u v btn m) x y
308+ V.EvMouseUp x y btn -> mouse (\u v -> V.EvMouseUp u v btn) x y
315+ , y >= t + h ] = Nothing
317+ Just (con (x - l) (y - t))
319+-- | Information about a drag operation
321+ { _drag_from :: (Int, Int) -- ^ Where the drag began
322+ , _drag_to :: (Int, Int) -- ^ Where the mouse currently is
323+ , _drag_button :: V.Button -- ^ Which mouse button is dragging
324+ , _drag_modifiers :: [V.Modifier] -- ^ What modifiers are held
325+ , _drag_end :: Bool -- ^ Whether the drag ended (the mouse button was released)
327+ deriving (Eq, Ord, Show)
329+-- | Converts raw vty mouse drag events into an event stream of 'Drag's
331+ :: (Reflex t, MonadFix m, MonadHold t m, HasVtyInput t m)
336+ let f :: Maybe Drag -> V.Event -> Maybe Drag
338+ V.EvMouseDown x y btn' mods
339+ | btn == btn' -> Just $ Drag (x,y) (x,y) btn' mods False
340+ | otherwise -> Nothing
342+ f (Just (Drag from _ _ mods end)) = \case
343+ V.EvMouseDown x y btn' mods'
344+ | end && btn == btn' -> Just $ Drag (x,y) (x,y) btn' mods' False
345+ | btn == btn' -> Just $ Drag from (x,y) btn mods' False
346+ | otherwise -> Nothing -- Ignore other buttons.
347+ V.EvMouseUp x y (Just btn')
349+ | btn == btn' -> Just $ Drag from (x,y) btn mods True
350+ | otherwise -> Nothing
351+ V.EvMouseUp x y Nothing -- Terminal doesn't specify mouse up button,
352+ -- assume it's the right one.
354+ | otherwise -> Just $ Drag from (x,y) btn mods True
356+ rec let newDrag = attachWithMaybe f (current dragD) inp
357+ dragD <- holdDyn Nothing $ Just <$> newDrag
358+ return (fmapMaybe id $ updated dragD)
360+-- | Mouse down events for a particular mouse button
362+ :: (Reflex t, Monad m, HasVtyInput t m)
364+ -> m (Event t MouseDown)
367+ return $ fforMaybe i $ \case
368+ V.EvMouseDown x y btn' mods -> if btn == btn'
369+ then Just $ MouseDown btn' (x, y) mods
373+-- | Mouse up events for a particular mouse button
375+ :: (Reflex t, Monad m, HasVtyInput t m)
376+ => m (Event t MouseUp)
379+ return $ fforMaybe i $ \case
380+ V.EvMouseUp x y btn' -> Just $ MouseUp btn' (x, y)
383+-- | Information about a mouse down event
384+data MouseDown = MouseDown
385+ { _mouseDown_button :: V.Button
386+ , _mouseDown_coordinates :: (Int, Int)
387+ , _mouseDown_modifiers :: [V.Modifier]
389+ deriving (Eq, Ord, Show)
557−-- * Misc
391+-- | Information about a mouse up event
392+data MouseUp = MouseUp
393+ { _mouseUp_button :: Maybe V.Button
394+ , _mouseUp_coordinates :: (Int, Int)
396+ deriving (Eq, Ord, Show)
398+-- | Mouse scroll direction
399+data ScrollDirection = ScrollDirection_Up | ScrollDirection_Down
400+ deriving (Eq, Ord, Show)
402+-- | Produce an event that fires when the mouse wheel is scrolled
404+ :: (Reflex t, Monad m, HasVtyInput t m)
405+ => m (Event t ScrollDirection)
407+ up <- mouseDown V.BScrollUp
408+ down <- mouseDown V.BScrollDown
410+ [ ScrollDirection_Up <$ up
411+ , ScrollDirection_Down <$ down
414+-- | Type synonym for a key and modifier combination
415+type KeyCombo = (V.Key, [V.Modifier])
417+-- | Emits an event that fires on a particular key press (without modifiers)
418+key :: (Monad m, Reflex t, HasVtyInput t m) => V.Key -> m (Event t KeyCombo)
419+key = keyCombos . Set.singleton . (,[])
421+-- | Emits an event that fires on particular key presses (without modifiers)
422+keys :: (Monad m, Reflex t, HasVtyInput t m) => [V.Key] -> m (Event t KeyCombo)
423+keys = keyCombos . Set.fromList . fmap (,[])
425+-- | Emit an event that fires whenever the provided key combination occurs
427+ :: (Reflex t, Monad m, HasVtyInput t m)
429+ -> m (Event t KeyCombo)
430+keyCombo = keyCombos . Set.singleton
432+-- | Emit an event that fires whenever any of the provided key combinations occur
434+ :: (Reflex t, Monad m, HasVtyInput t m)
436+ -> m (Event t KeyCombo)
439+ return $ fforMaybe i $ \case
440+ V.EvKey k m -> if Set.member (k, m) ks
445+-- | A plain split of the available space into vertically stacked panes.
446+-- No visual separator is built in here.
447+splitV :: (Reflex t, Monad m, MonadNodeId m, HasVtyWidgetCtx t m, HasDisplaySize t m, HasVtyInput t m)
448+ => Dynamic t (Int -> Int)
449+ -- ^ Function used to determine size of first pane based on available size
450+ -> Dynamic t (Bool, Bool)
451+ -- ^ How to focus the two sub-panes, given that we are focused.
453+ -- ^ Widget for first pane
455+ -- ^ Widget for second pane
457+splitV sizeFunD focD wA wB = do
460+ let regA = Region 0 0 <$> dw <*> (sizeFunD <*> dh)
461+ regB = Region 0 <$> (_region_height <$> regA) <*> dw <*> liftA2 (-) dh (_region_height <$> regA)
462+ ra <- pane regA (fst <$> focD) wA
463+ rb <- pane regB (snd <$> focD) wB
466+-- | A plain split of the available space into horizontally stacked panes.
467+-- No visual separator is built in here.
468+splitH :: (Reflex t, Monad m, MonadNodeId m, HasDisplaySize t m, HasVtyWidgetCtx t m, HasVtyInput t m)
469+ => Dynamic t (Int -> Int)
470+ -- ^ Function used to determine size of first pane based on available size
471+ -> Dynamic t (Bool, Bool)
472+ -- ^ How to focus the two sub-panes, given that we are focused.
474+ -- ^ Widget for first pane
476+ -- ^ Widget for second pane
478+splitH sizeFunD focD wA wB = do
481+ let regA = Region 0 0 <$> (sizeFunD <*> dw) <*> dh
482+ regB = Region <$> (_region_width <$> regA) <*> 0 <*> liftA2 (-) dw (_region_width <$> regA) <*> dh
483+ liftA2 (,) (pane regA (fmap fst focD) wA) (pane regB (fmap snd focD) wB)
485+-- | A split of the available space into two parts with a draggable separator.
486+-- Starts with half the space allocated to each, and the first pane has focus.
487+-- Clicking in a pane switches focus.
488+splitVDrag :: (Reflex t, MonadFix m, MonadHold t m, MonadNodeId m, HasDisplaySize t m, HasVtyInput t m, HasVtyWidgetCtx t m)
493+splitVDrag wS wA wB = do
496+ h0 <- sample $ current dh -- TODO
497+ dragE <- drag V.BLeft
498+ let splitter0 = h0 `div` 2
499+ rec splitterCheckpoint <- holdDyn splitter0 $ leftmost [fst <$> ffilter snd dragSplitter, resizeSplitter]
500+ splitterPos <- holdDyn splitter0 $ leftmost [fst <$> dragSplitter, resizeSplitter]
501+ splitterFrac <- holdDyn ((1::Double) / 2) $ ffor (attach (current dh) (fst <$> dragSplitter)) $ \(h, x) ->
502+ fromIntegral x / max 1 (fromIntegral h)
503+ let dragSplitter = fforMaybe (attach (current splitterCheckpoint) dragE) $
504+ \(splitterY, Drag (_, fromY) (_, toY) _ _ end) ->
505+ if splitterY == fromY then Just (toY, end) else Nothing
506+ regA = Region 0 0 <$> dw <*> splitterPos
507+ regS = Region 0 <$> splitterPos <*> dw <*> 1
508+ regB = Region 0 <$> (splitterPos + 1) <*> dw <*> (dh - splitterPos - 1)
509+ resizeSplitter = ffor (attach (current splitterFrac) (updated dh)) $
510+ \(frac, h) -> round (frac * fromIntegral h)
511+ focA <- holdDyn True $ leftmost
515+ (mA, rA) <- pane regA focA $ withMouseDown wA
516+ pane regS (pure False) wS
517+ (mB, rB) <- pane regB (not <$> focA) $ withMouseDown wB
520+ withMouseDown x = do
521+ m <- mouseDown V.BLeft
525+-- | Fill the background with a particular character.
526+fill :: (HasDisplaySize t m, ImageWriter t m) => Char -> m ()
530+ let fillImg = current $ liftA2 (\w h -> [V.charFill V.defAttr c w h]) dw dh
533+-- | Fill the background with the bottom
534+hRule :: (HasDisplaySize t m, ImageWriter t m) => BoxStyle -> m ()
535+hRule boxStyle = fill (_boxStyle_s boxStyle)
537+-- | Defines a set of symbols to use to draw the outlines of boxes
538+-- C.f. https://en.wikipedia.org/wiki/Box-drawing_character
539+data BoxStyle = BoxStyle
540+ { _boxStyle_nw :: Char
541+ , _boxStyle_n :: Char
542+ , _boxStyle_ne :: Char
543+ , _boxStyle_e :: Char
544+ , _boxStyle_se :: Char
545+ , _boxStyle_s :: Char
546+ , _boxStyle_sw :: Char
547+ , _boxStyle_w :: Char
550+instance Default BoxStyle where
551+ def = singleBoxStyle
553+-- | A box style that uses hyphens and pipe characters. Doesn't handle
554+-- corners very well.
555+hyphenBoxStyle :: BoxStyle
556+hyphenBoxStyle = BoxStyle '-' '-' '-' '|' '-' '-' '-' '|'
558+-- | A single line box style
559+singleBoxStyle :: BoxStyle
560+singleBoxStyle = BoxStyle '┌' '─' '┐' '│' '┘' '─' '└' '│'
562+-- | A thick single line box style
563+thickBoxStyle :: BoxStyle
564+thickBoxStyle = BoxStyle '┏' '━' '┓' '┃' '┛' '━' '┗' '┃'
566+-- | A double line box style
567+doubleBoxStyle :: BoxStyle
568+doubleBoxStyle = BoxStyle '╔' '═' '╗' '║' '╝' '═' '╚' '║'
570+-- | A single line box style with rounded corners
571+roundedBoxStyle :: BoxStyle
572+roundedBoxStyle = BoxStyle '╭' '─' '╮' '│' '╯' '─' '╰' '│'
574+-- | Draws a titled box in the provided style and a child widget inside of that box
575+boxTitle :: (Monad m, Reflex t, MonadNodeId m, HasDisplaySize t m, ImageWriter t m, HasVtyWidgetCtx t m, HasVtyInput t m)
576+ => Behavior t BoxStyle
580+boxTitle boxStyle title child = do
583+ let boxReg = Region 0 0 <$> dw <*> dh
584+ innerReg = Region 1 1 <$> (subtract 2 <$> dw) <*> (subtract 2 <$> dh)
585+ tellImages (boxImages <$> boxStyle <*> current boxReg)
586+ tellImages (fmap (\r -> [regionBlankImage r]) (current innerReg))
587+ pane innerReg (pure True) child
589+ boxImages :: BoxStyle -> Region -> [Image]
590+ boxImages style (Region left top width height) =
591+ let right = left + width - 1
592+ bottom = top + height - 1
594+ [ withinImage (Region (left + 1) top (width - 2) 1) $
596+ hPadText title (_boxStyle_n style) (width - 2)
597+ , withinImage (Region right (top + 1) 1 (height - 2)) $
598+ V.charFill V.defAttr (_boxStyle_e style) 1 (height - 2)
599+ , withinImage (Region (left + 1) bottom (width - 2) 1) $
600+ V.charFill V.defAttr (_boxStyle_s style) (width - 2) 1
601+ , withinImage (Region left (top + 1) 1 (height - 2)) $
602+ V.charFill V.defAttr (_boxStyle_w style) 1 (height - 2)
605+ [ withinImage (Region left top 1 1) $
606+ V.char V.defAttr (_boxStyle_nw style)
607+ , withinImage (Region right top 1 1) $
608+ V.char V.defAttr (_boxStyle_ne style)
609+ , withinImage (Region right bottom 1 1) $
610+ V.char V.defAttr (_boxStyle_se style)
611+ , withinImage (Region left bottom 1 1) $
612+ V.char V.defAttr (_boxStyle_sw style)
614+ in sides ++ if width > 1 && height > 1 then corners else []
615+ hPadText :: T.Text -> Char -> Int -> T.Text
616+ hPadText t c l = if lt >= l
618+ else left <> t <> right
622+ mkHalf n = T.replicate (n `div` 2) (T.singleton c)
623+ left = mkHalf $ delta + 1
624+ right = mkHalf delta
626+-- | A box without a title
627+box :: (Monad m, Reflex t, MonadNodeId m, HasDisplaySize t m, ImageWriter t m, HasVtyWidgetCtx t m, HasVtyInput t m)
628+ => Behavior t BoxStyle
631+box boxStyle = boxTitle boxStyle mempty
633+-- | A box whose style is static
635+ :: (Monad m, Reflex t, MonadNodeId m, HasDisplaySize t m, ImageWriter t m, HasVtyWidgetCtx t m, HasVtyInput t m)
639+boxStatic = box . pure
641+-- | Configuration options for displaying "rich" text
642+data RichTextConfig t = RichTextConfig
643+ { _richTextConfig_attributes :: Behavior t V.Attr
646+instance Reflex t => Default (RichTextConfig t) where
647+ def = RichTextConfig $ pure V.defAttr
649+-- | A widget that displays text with custom time-varying attributes
651+ :: (Reflex t, Monad m, HasDisplaySize t m, ImageWriter t m)
657+ let img = (\w a s -> [wrapText w a s])
659+ <*> _richTextConfig_attributes cfg
663+ wrapText maxWidth attrs = V.vertCat
664+ . concatMap (fmap (V.string attrs . T.unpack) . TZ.wrapWithOffset maxWidth 0)
667+-- | Renders text, wrapped to the container width
669+ :: (Reflex t, Monad m, HasDisplaySize t m, ImageWriter t m)
674+-- | Scrollable text widget. The output pair exposes the current scroll position and total number of lines (including those
677+ :: forall t m. (Reflex t, MonadHold t m, MonadFix m, HasDisplaySize t m, HasVtyInput t m, ImageWriter t m)
679+ -- ^ Number of lines to scroll by
681+ -> m (Behavior t (Int, Int))
682+ -- ^ (Current scroll position, total number of lines)
683+scrollableText scrollBy t = do
685+ let imgs = wrap <$> current dw <*> t
687+ kdown <- key V.KDown
689+ let requestedScroll :: Event t Int
690+ requestedScroll = leftmost
694+ ScrollDirection_Up -> (-1)
695+ ScrollDirection_Down -> 1
698+ updateLine maxN delta ix = min (max 0 (ix + delta)) maxN
699+ lineIndex :: Dynamic t Int <- foldDyn (\(maxN, delta) ix -> updateLine (maxN - 1) delta ix) 0 $
700+ attach (length <$> imgs) requestedScroll
701+ tellImages $ fmap ((:[]) . V.vertCat) $ drop <$> current lineIndex <*> imgs
702+ return $ (,) <$> ((+) <$> current lineIndex <*> pure 1) <*> (length <$> imgs)
704+ wrap maxWidth = concatMap (fmap (V.string V.defAttr . T.unpack) . TZ.wrapWithOffset maxWidth 0) . T.split (=='\n')
706+-- | Renders any behavior whose value can be converted to
709+ :: (Reflex t, Monad m, Show a, HasDisplaySize t m, ImageWriter t m)
712+display a = text $ T.pack . show <$> a
559-- | A widget that draws nothing
714-- | A widget that draws nothing
560blank :: Monad m => m ()
715blank :: Monad m => m ()