Documentation

Fields

• _widTs :: Int

  The timestamp when the instance was created.

• _widPath :: Path

  The path at creation time.

Fields

• _wrNode :: WidgetNode s e

  The updated widget node.

• _wrRequests :: Seq (WidgetRequest s e)

  The widget requests.

Fields

• _weOs :: Text

  The OS of the host.

• _weFontManager :: FontManager

  Provides helper funtions for calculating text size.

• _weFindByPath :: Path -> Maybe WidgetNodeInfo

  Returns the information of a node given a path from root, if any.

• _weMainButton :: Button

  The mouse button that is considered main.

• _weContextButton :: Button

  The mouse button that is considered as secondary or context button.

• _weTheme :: Theme

  The active theme. Some widgets derive their base style from this.

• _weWindowSize :: Size

  The main window size.

• _weWidgetShared :: MVar (Map Text WidgetShared)

  The active map of shared data.

• _weWidgetKeyMap :: WidgetKeyMap s e

  The active map of WidgetKey -> WidgetNode, if any.

• _weHoveredPath :: Maybe Path

  The currently hovered path, if any.

• _weFocusedPath :: Path

  The currently focused path. There's always one, even if it's empty.

• _weOverlayPath :: Maybe Path

  The current overlay path, if any.

• _weDragStatus :: Maybe (Path, WidgetDragMsg)

  The current drag message and source path, if any is active.

• _weMainBtnPress :: Maybe (Path, Point)

  Indicates the path and position where the main button was pressed.

• _weCursor :: Maybe (Path, CursorIcon)

  The current active cursor, and the path that set it.

• _weModel :: s

  The current user model.

• _weInputStatus :: InputStatus

  The input status, mainly mouse and keyboard.

• _weTimestamp :: Timestamp

  The timestamp when this cycle started.

• _weThemeChanged :: Bool

  Whether the theme changed in this cycle. Should be considered when a widget avoids merging as optimization, as the styles may have changed.

• _weInTopLayer :: Point -> Bool

  Indicates whether the current widget is in a top layer (zstack).

• _weLayoutDirection :: LayoutDirection

  The current layout direction.

• _weViewport :: Rect

  The active viewport. This may be smaller than the widget's viewport, if it's currently inside a scroll or similar.

• _weOffset :: Point

  The current accumulated offset. This can be affected by scroll.

Fields

• _wniWidgetType :: !WidgetType

  Type of the widget.

• _wniWidgetId :: !WidgetId

  The identifier at creation time of the widget (runtime generated).

• _wniKey :: Maybe WidgetKey

  Key/Identifier of the widget (user provided). Used for merging.

• _wniPath :: !Path

  The path of the instance in the widget tree, as a set of indexes.

• _wniSizeReqW :: !SizeReq

  The requested width for the widget. The one in style takes precedence.

• _wniSizeReqH :: !SizeReq

  The requested height for the widget. The one in style takes precedence.

• _wniEnabled :: !Bool

  Indicates if the widget is enabled for user interaction.

• _wniVisible :: !Bool

  Indicates if the widget is visible.

• _wniFocusable :: !Bool

  Indicates whether the widget can receive focus.

• _wniViewport :: !Rect

  The area of the window where the widget can draw. Could be out of bounds or partially invisible if inside a scroll. The viewport on WidgetEnv defines what is currently visible.

• _wniStyle :: Style

  Style attributes of the widget instance.

Fields

• _wnWidget :: Widget s e

  The actual widget.

• _wnInfo :: WidgetNodeInfo

  Information about the instance.

• _wnChildren :: Seq (WidgetNode s e)

  The children widgets, if any.

Fields

• _winInfo :: WidgetNodeInfo

  Information about the instance.

• _winState :: Maybe WidgetState

  The widget state, if any.

• _winChildren :: Seq WidgetInstanceNode

  The children widget, if any.

Fields

• widgetInit :: WidgetEnv s e -> WidgetNode s e -> WidgetResult s e

  Initializes the given node. This could include rebuilding the widget in case internal state needs to use model/environment information, generate user events or make requests to the runtime.

  Arguments:

  • The widget environment.
  • The widget node.

  Returns:

  • The result of the init operation.
• widgetMerge :: WidgetEnv s e -> WidgetNode s e -> WidgetNode s e -> WidgetResult s e

  Merges the current node with the node it matched with during the merge process. Receives the newly created node (whose *init* function is not called), the previous node and the state extracted from that node. This process is widget dependent, and may use or ignore the previous state depending on newly available information.

  In general, you want to at least keep the previous state unless the widget is stateless or only consumes model/environment information.

  Arguments:

  • The widget environment.
  • The widget node.
  • The previous widget node.

  Returns:

  • The result of the merge operation.
• widgetDispose :: WidgetEnv s e -> WidgetNode s e -> WidgetResult s e

  Disposes the current node. Only used by widgets which allocate resources during init or merge, and will usually involve requests to the runtime.

  Arguments:

  • The widget environment.
  • The widget node.

  Returns:

  • The result of the dispose operation.
• widgetGetState :: WidgetEnv s e -> WidgetNode s e -> Maybe WidgetState

  Returns the current internal state, which can later be used when during the merge process.

  Arguments:

  • The widget environment.
  • The widget node.

  Returns:

  • The internal state, if any.
• widgetGetInstanceTree :: WidgetEnv s e -> WidgetNode s e -> WidgetInstanceNode

  Returns information about the instance and its children.

  Arguments:

  • The widget environment.
  • The widget node.

  Returns:

  • The untyped node information.
• widgetFindNextFocus :: WidgetEnv s e -> WidgetNode s e -> FocusDirection -> Path -> Maybe WidgetNodeInfo

  Returns the next focusable node. What next/previous is, depends on how the widget works. Moving left to right, top to bottom is usually considered forward.

  Arguments:

  • The widget environment.
  • The widget node.
  • The direction in which focus is moving.
  • The path to start the search from.

  Returns:

  • The next focusable node info.
• widgetFindByPoint :: WidgetEnv s e -> WidgetNode s e -> Path -> Point -> Maybe WidgetNodeInfo

  Returns the currently hovered widget, if any.

  Arguments:

  • The widget environment.
  • The widget node.
  • The path to start the search from.
  • The point to test for.

  Returns:

  • The hovered child index, if any.
• widgetFindBranchByPath :: WidgetEnv s e -> WidgetNode s e -> Path -> Seq WidgetNodeInfo

  Returns the widget matching the given path, plus all its parents.

  Arguments:

  • The widget environment.
  • The widget node.
  • The path to search for.

  Returns:

  • The sequence of widgets up to path, ordered from root to target.
• widgetHandleEvent :: WidgetEnv s e -> WidgetNode s e -> Path -> SystemEvent -> Maybe (WidgetResult s e)

  Receives a System event and, optionally, returns a result. This can include an updated version of the widget (in case it has internal state), user events or requests to the runtime.

  Arguments:

  • The widget environment.
  • The widget node.
  • The target path of the event.
  • The SystemEvent to handle.

  Returns:

  • The result of handling the event, if any.
• widgetHandleMessage :: forall i. Typeable i => WidgetEnv s e -> WidgetNode s e -> Path -> i -> Maybe (WidgetResult s e)

  Receives a message and, optionally, returns a result. This can include an updated version of the widget (in case it has internal state), user events or requests to the runtime. There is no validation regarding the message type, and the widget should take care of _casting_ to the correct type using "Data.Typeable.cast"

  Arguments:

  • The widget environment.
  • The widget node.
  • The target path of the message.
  • The message to handle.

  Returns:

  • The result of handling the message, if any.
• widgetGetSizeReq :: WidgetEnv s e -> WidgetNode s e -> (SizeReq, SizeReq)

  Returns the preferred size for the widget.

  Arguments:

  • The widget environment.
  • The widget node.

  Returns:

  • The horizontal and vertical requirements.
• widgetResize :: WidgetEnv s e -> WidgetNode s e -> Rect -> (Path -> Bool) -> WidgetResult s e

  Resizes the widget to the provided size.

  Arguments:

  • The widget environment.
  • The widget node.
  • The new viewport.
  • Helper to checks if a given path, or its children, requested resize.

  Returns:

  • The result of resizing the widget.
• widgetRender :: WidgetEnv s e -> WidgetNode s e -> Renderer -> IO ()

  Renders the widget's content using the given Renderer.

  Arguments:

  • The widget environment.
  • The widget node.
  • The renderer, providing low level drawing functions.

  Returns:

  • The IO action with rendering instructions.