    -- #hide
    --------------------------------------------------------------------------------
    -- |
    -- Module      :  Graphics.Rendering.OpenGL.GL.PixelData
    -- Copyright   :  (c) Sven Panne 2002-2009
    -- License     :  BSD-style (see the file libraries/OpenGL/LICENSE)
    --
    -- Maintainer  :  sven.panne@aedion.de
    -- Stability   :  stable
    -- Portability :  portable
    --
    -- This is a purely internal helper module.
    --
    --------------------------------------------------------------------------------

    module Graphics.Rendering.OpenGL.GL.PixelData (
       PixelData(..), withPixelData
    ) where

    import Foreign.Ptr ( Ptr )
    import Graphics.Rendering.OpenGL.GL.BasicTypes ( GLenum )
    import Graphics.Rendering.OpenGL.GL.DataType ( DataType, marshalDataType )
    import Graphics.Rendering.OpenGL.GL.PixelFormat (
       PixelFormat, marshalPixelFormat )

    --------------------------------------------------------------------------------

    data PixelData a = PixelData PixelFormat DataType (Ptr a)
    #ifdef __HADDOCK__
    -- Help Haddock a bit, because it doesn't do any instance inference.
    instance Eq (PixelData a)
    instance Ord (PixelData a)
    instance Show (PixelData a)
    #else
       deriving ( Eq, Ord, Show )
    #endif

    withPixelData :: PixelData a -> (GLenum -> GLenum -> Ptr a -> b) -> b
    withPixelData (PixelData pixelFormat dataType ptr) f =
       f (marshalPixelFormat pixelFormat) (marshalDataType dataType) ptr