First example EVER on GTK and Haskell, Render Primitives

I give you the first example on the Internet, rendering a primitive, point and rectangle. Next, double buffering.

-- The Glorious Glasgow Haskell Compilation System, version 6.12.3
-- ghc --make SimpleCells.hs
-- See: http://code.google.com/p/ainotebook/
--
-- Berlin Brown

import Graphics.UI.Gtk
import Graphics.UI.Gtk.Gdk.GC
import Graphics.UI.Gtk hiding (Color, Point, Object)

defaultFgColor :: Color
defaultFgColor = Color 65535 65535 65535

defaultBgColor :: Color
defaultBgColor = Color 0 0 0

renderScene d ev = do
 dw    <- widgetGetDrawWindow d
 (w, h) <- widgetGetSize d
 gc     <- gcNew dw
 let fg = Color (round (65535 * 205))
     (round (65535 * 0))
     (round (65535 * 0))
 gcSetValues gc $ newGCValues { foreground = fg }
 drawPoint dw gc (120, 120)
 drawPoint dw gc (22, 22)
 drawRectangle dw gc True 20 20 20 20
 return True

main :: IO () 
main = do
 initGUI
 window  <- windowNew
 drawing <- drawingAreaNew
 windowSetTitle window "Cells"
 containerAdd window drawing
 let bg = Color  (round (65535 * 205))
     (round (65535 * 205))
     (round (65535 * 255))
 widgetModifyBg drawing StateNormal bg
 onExpose drawing (renderScene drawing)
 
 onDestroy window mainQuit
 windowSetDefaultSize window 800 600
 windowSetPosition window WinPosCenter
 widgetShowAll window
 mainGUI
 
-- End of File