setPixel :: Int -> Int -> JSString -> Pixels -> Pixels
setPixel x y c p =
  let r  = p IM.! y
      r' = IM.insert x c r
  in  r' `seq` IM.insert y r' p
setPixel :: Int -> Int -> JSString -> Pixels -> Pixels
setPixel x y c p =
  let r  = p IM.! y
      r' = IM.insert x c r
  in  r' `seq` IM.insert y r' p
setPixel x y c p =
  let r  = p IM.! y
      r' = IM.insert x c r
  in  r' `seq` IM.insert y r' p