Frame をスクリーン中央に位置させる(frameCenter)

module Main where
import Graphics.UI.WX
import Graphics.UI.WXCore.Frame (frameCenter)

main :: IO ()
    -- start :: IO a -> IO () -- Defined in Graphics.UI.WX
main = start hello

{-
frameCenter :: Frame a -> IO ()
Center the frame on the screen.
-}

hello :: IO ()
hello
  = do f    <- frame    [text := "Hello!"]
       quit <- button f [text := "Quit", on command := close f]
       set f [layout := widget quit]
       frameCenter f