-- Copyright 2006 mutantlemon.com

module GuiDrawUtil where

-- Code taken from gtk2hs fastdraw demo

import Graphics.UI.Gtk

updateCanvas :: DrawingArea -> Pixbuf -> Event -> IO Bool
updateCanvas canvas pb Expose { eventRegion = region } = do
  win <- drawingAreaGetDrawWindow canvas
  gc <- gcNew win
  width  <- pixbufGetWidth pb
  height <- pixbufGetHeight pb
  pbregion <- regionRectangle (Rectangle 0 0 width height)
  regionIntersect region pbregion
  rects <- regionGetRectangles region
--  putStrLn ("redrawing: "++show rects)
  (flip mapM_) rects $ \(Rectangle x y w h) -> do
    drawPixbuf win gc pb x y x y w h RgbDitherNone 0 0
  return True

{-# INLINE doFromTo #-}
-- do the action for [from..to], ie it's inclusive.
doFromTo :: Int -> Int -> (Int -> IO ()) -> IO ()
doFromTo from to action =
  let loop n | n > to   = return ()
             | otherwise = do action n
                              loop (n+1)
   in loop from