KeyMouse.hs

{-# LANGUAGE RankNTypes #-}
{-# OPTIONS_HADDOCK hide #-}

module Brillo.Internals.Interface.ViewState.KeyMouse (callback_viewState_keyMouse)
where

import Brillo.Data.ViewState
import Brillo.Internals.Interface.Backend
import Brillo.Internals.Interface.Event
import Data.IORef


{-| Callback to handle keyboard and mouse button events
     for controlling the 'ViewState'.
-}
callback_viewState_keyMouse
  :: IORef ViewState
  -> Callback
callback_viewState_keyMouse viewStateRef =
  KeyMouse (viewState_keyMouse viewStateRef)


viewState_keyMouse :: IORef ViewState -> KeyboardMouseCallback
viewState_keyMouse viewStateRef stateRef key keyState keyMods pos =
  do
    viewState <- readIORef viewStateRef
    ev <- keyMouseEvent stateRef key keyState keyMods pos
    case updateViewStateWithEventMaybe ev viewState of
      Nothing -> return ()
      Just viewState' ->
        do
          viewStateRef `writeIORef` viewState'
          postRedisplay stateRef