gtk2hs drawingArea

canvas.hs

import Graphics.UI.Gtk 
import Graphics.Rendering.Cairo
import Control.Monad.Trans 

main :: IO () 
main = do 
  initGUI  
  window <- windowNew 
  vbox <- vBoxNew False 0 
  canvas <- drawingAreaNew   
  set canvas [ widgetWidthRequest := 400 
             , widgetHeightRequest := 400 ]   
  boxPackStart vbox canvas PackNatural 0   
  containerAdd window vbox 
  canvas `on` exposeEvent $ tryEvent $ do 
    win <- liftIO $ widgetGetDrawWindow canvas 
    liftIO . renderWithDrawable win $ do 
      setSourceRGBA 0 0 0 1 
      setLineWidth 1.0
      moveTo 100 100 
      lineTo 200 200 
      stroke
  window `on` deleteEvent $ tryEvent $ do 
    liftIO $ mainQuit 
  widgetShowAll window
  mainGUI