SneathLane.Widget

Widgets

data Widget f z

Atom of a sneath lane application

Constructors

Finish z

Continue (f (OutputFn f z)) (Maybe (MouseOut (Widget f z))) (Maybe (Animate (Widget f z))) (WidgetFocus f z)

Instances

Functor f => Monad (Widget f)

Functor f => Functor (Widget f)

Functor f => Applicative (Widget f)

data WidgetFocus f z

Determines the focus behavior of the widget

Constructors

NotFocusable

Widget can not take keyboard focus

Focusable (Widget f z) (Widget f z)

Widget can take keyboard focus, but does not have it now

Focused (Widget f z) (Widget f z, Bool) (Widget f z, Bool) (HandleKey (Widget f z))

Widget has keyboard focus

zipW :: (Functor f, Functor g, Functor h) => (f (OutputFn h z) -> g (OutputFn h z) -> h (OutputFn h z)) -> Widget f z -> Widget g z -> Widget h z

Combine two widgets to run in parallel as a single widget

Build Widgets

graphicWidget :: Functor f => Maybe String -> f () -> Widget f a

A widget which just shows a constant graphic output.

above :: Widget GraphicTree z -> Widget GraphicTree z -> Widget GraphicTree z

Combine two widgets one above the other

combineAbove :: GraphicTree a -> GraphicTree a -> GraphicTree a

beside :: Widget GraphicTree z -> Widget GraphicTree z -> Widget GraphicTree z

Combine two widgets side by side

combineBeside :: GraphicTree a -> GraphicTree a -> GraphicTree a

mapGraphic :: Functor f1 => (f1 (MouseEv -> (Maybe String, Widget f z)) -> f (OutputFn f z)) -> Widget f1 z -> Widget f z

mapWidgetFocus :: (Widget t t1 -> Widget f z) -> WidgetFocus t t1 -> WidgetFocus f z

Run Widgets

runOnCanvas :: (forall z. Double -> Widget GraphicTree z) -> IO ()

Create a Canvas element filling the browser viewport, and run the given Widget there

Graphics

data GraphicTree :: * -> * where

A tree of graphics, used as widget output type. FMap functions are stored in the tree instead of being mapped over the leaves, so that tree reconstruction is fast when a widget changes. This is why GraphicTree is a GADT.

Offset: a sub-tree translated by a point

Branch: Two sub-trees; graphicTreeBounds are cached for each

Leaf: A leaf, consisting of a single graphic element

FMap: A graphic tree composed with a function.

Constructors

Clip :: Rect -> GraphicTree a -> GraphicTree a

Offset :: Point -> GraphicTree a -> GraphicTree a

Branch :: Rect -> GraphicTree a -> Rect -> GraphicTree a -> GraphicTree a

Leaf :: Graphic -> GraphicTree ()

FMap :: (a -> b) -> GraphicTree a -> GraphicTree b

Instances

Functor GraphicTree

graphicList :: [Graphic] -> GraphicTree ()

Construct a graphic tree from a nonempty list of graphics.

graphicTreeBounds :: GraphicTree a -> Rect

Find a rectangle containing the entire contents of the graphic tree

Events

data MouseEv

Constructors

EvMouseUp Point MouseButton

EvMouseDown Point MouseButton

EvMouseMove Point

data MouseButton

Which mouse button (if any) was being pressed

Constructors

RightButton

LeftButton

data Key

Constructors

EvKeyDown Int Bool

EvKeyUp Int Bool

EvKeyInput JSString

Utility

balancedFold :: (a -> a -> a) -> [a] -> a

Apply a fold in a balanced fashion over a list. Recommended for combining lists of widgets, so that the widget tree has logarithmic depth.

Type synonyms

type OutputFn f z = MouseEv -> (Maybe String, Widget f z)

type Animate a = TimeDifference -> a

type MouseOut a = a

type HandleKey a = Key -> a

type TimeDifference = Double