content: {-# LANGUAGE RankNTypes #-}
  
  -- We export this stuff separately so we don't clutter up the
  -- API of the Graphics.Gloss module.
  
  -- | Simulate mode is for producing an animation of some model who's picture
  --   changes over finite time steps. The behavior of the model can also depent
  --   on the current `ViewPort`.
  module Graphics.Gloss.Interface.IO.Simulate
          ( module Graphics.Gloss.Data.Display
          , module Graphics.Gloss.Data.Picture
          , module Graphics.Gloss.Data.Color
          , simulateIO
          , ViewPort(..))
  where
  import Graphics.Gloss.Data.Display
  import Graphics.Gloss.Data.Picture
  import Graphics.Gloss.Data.Color
  import Graphics.Gloss.Data.ViewPort
  import Graphics.Gloss.Internals.Interface.Simulate
  import Graphics.Gloss.Internals.Interface.Backend
  
  
  simulateIO :: forall model
          .  Display               -- ^ Display mode.
          -> Color                 -- ^ Background color.
          -> Int                   -- ^ Number of simulation steps to take for each second of real time.
          -> model                 -- ^ The initial model.
          -> (model -> IO Picture) -- ^ A function to convert the model to a picture.
          -> (ViewPort -> Float -> model -> IO model)
                                   -- ^ A function to step the model one iteration. It is passed the
                                   --     current viewport and the amount of time for this simulation
                                   --     step (in seconds).
          -> IO ()
  
  simulateIO = simulateWithBackendIO defaultBackendState
  