NullWidget.hs

module UI.Widgets.NullWidget where

import Common
import UI.Widgets.Common

data NullWidget = NullWidget { nwDimensions :: Dimensions, nwPos :: ScreenPos }

instance Widget NullWidget where
  hasCapability (DrawableCap _) = Just Dict
  hasCapability (MoveableCap _) = Just Dict
  hasCapability _               = Nothing

instance Moveable NullWidget where
  move _ _ = pure ()
  getPos r = nwPos <$> readWRef r
  getDim r = nwDimensions <$> readWRef r
  resize r fn = modifyWRef r (\w -> w { nwDimensions = fn (nwDimensions w) })

instance Drawable NullWidget where
  setVisibility _ _ = pure ()
  getVisibility _ = pure True
  draw _ = pure ()

nullWidget :: NullWidget
nullWidget = NullWidget (Dimensions 0 0) (ScreenPos 0 0)