    -----------------------------------------------------------------------------
    -- |
    -- Module      :  Graphics.X11.Xlib.Color
    -- Copyright   :  (c) Alastair Reid, 1999-2003
    -- License     :  BSD-style (see the file libraries/base/LICENSE)
    --
    -- Maintainer  :  libraries@haskell.org
    -- Stability   :  provisional
    -- Portability :  portable
    --
    -- A collection of FFI declarations for interfacing with Xlib Colors.
    --
    -----------------------------------------------------------------------------

    module Graphics.X11.Xlib.Color(

            lookupColor,
            allocNamedColor,
            allocColor,
            parseColor,
            freeColors,
            storeColor,
            queryColor,
            queryColors,
            installColormap,
            uninstallColormap,
            copyColormapAndFree,
            createColormap,
            freeColormap,

            ) where

    import Graphics.X11.Types
    import Graphics.X11.Xlib.Types

    import Foreign
    import Foreign.C
    import Foreign.C.Types

    ----------------------------------------------------------------
    -- Color and Colormaps
    ----------------------------------------------------------------

    -- | interface to the X11 library function @XLookupColor()@.
    lookupColor :: Display -> Colormap -> String -> IO (Color, Color)
    lookupColor display colormap color_name =
            withCString color_name $ \c_color_name ->
            alloca $ \ exact_def_return ->
            alloca $ \ screen_def_return -> do
            throwIfZero "lookupColor" $
                    xLookupColor display colormap c_color_name
                            exact_def_return screen_def_return
            exact_def <- peek exact_def_return
            screen_def <- peek screen_def_return
            return (exact_def, screen_def)

    foreign import ccall unsafe "HsXlib.h XLookupColor"
            xLookupColor :: Display -> Colormap -> CString ->
                    Ptr Color -> Ptr Color -> IO Status

    -- TODO don't throw an exception.
    -- | interface to the X11 library function @XAllocNamedColor()@.
    allocNamedColor :: Display -> Colormap -> String -> IO (Color, Color)
    allocNamedColor display colormap color_name =
            withCString color_name $ \c_color_name ->
            alloca $ \ exact_def_return ->
            alloca $ \ screen_def_return -> do
            throwIfZero "allocNamedColor" $
                    xAllocNamedColor display colormap c_color_name
                            exact_def_return screen_def_return
            exact_def <- peek exact_def_return
            screen_def <- peek screen_def_return
            return (exact_def, screen_def)

    foreign import ccall unsafe "HsXlib.h XAllocNamedColor"
            xAllocNamedColor :: Display -> Colormap -> CString ->
                    Ptr Color -> Ptr Color -> IO Status

    -- | interface to the X11 library function @XAllocColor()@.
    allocColor :: Display -> Colormap -> Color -> IO Color
    allocColor display colormap color =
            with color $ \ color_ptr -> do
            throwIfZero "allocColor" $
                    xAllocColor display colormap color_ptr
            peek color_ptr

    foreign import ccall unsafe "HsXlib.h XAllocColor"
            xAllocColor :: Display -> Colormap -> Ptr Color -> IO Status

    -- | interface to the X11 library function @XParseColor()@.
    parseColor :: Display -> Colormap -> String -> IO Color
    parseColor display colormap color_spec =
            withCString color_spec $ \ spec ->
            alloca $ \ exact_def_return -> do
            throwIfZero "parseColor" $
                    xParseColor display colormap spec exact_def_return
            peek exact_def_return

    foreign import ccall unsafe "HsXlib.h XParseColor"
            xParseColor :: Display -> Colormap -> CString -> Ptr Color -> IO Status

    -- ToDo: Can't express relationship between arg4 and res1 properly (or arg5, res2)
    -- %errfun Zero XAllocColorCells :: Display -> Colormap -> Bool -> Int -> Int -> IO (ListPixel, ListPixel) using err = XAllocColorCells(arg1,arg2,arg3,arg4_size,res1,arg5_size,res2)

    -- ToDo: Can't express relationship between arg4 and res1 properly
    -- %errfun Zero XAllocColorPlanes :: Display -> Colormap -> Bool -> Int -> Int -> Int -> Int IO (ListPixel, Pixel, Pixel, Pixel) using err = XAllocColorPlanes(...)

    -- | interface to the X11 library function @XFreeColors()@.
    freeColors :: Display -> Colormap -> [Pixel] -> Pixel -> IO ()
    freeColors display colormap pixels planes =
            withArray pixels $ \ pixel_array ->
            xFreeColors display colormap pixel_array (fromIntegral (length pixels)) planes

    foreign import ccall unsafe "HsXlib.h XFreeColors"
            xFreeColors :: Display -> Colormap -> Ptr Pixel -> CInt -> Pixel -> IO ()

    -- | interface to the X11 library function @XStoreColor()@.
    storeColor :: Display -> Colormap -> Color -> IO ()
    storeColor display colormap color =
            with color $ \ color_ptr ->
            xStoreColor display colormap color_ptr

    foreign import ccall unsafe "HsXlib.h XStoreColor"
            xStoreColor  :: Display -> Colormap -> Ptr Color -> IO ()

    -- %fun XStoreColors :: Display -> Colormap -> ListColor -> IO ()
    -- %code XStoreColors(arg1,arg2,arg3,arg3_size)
    -- %fun XStoreNamedColor :: Display -> Colormap -> String -> Pixel -> PrimaryMask -> IO ()

    -- | interface to the X11 library function @XQueryColor()@.
    queryColor :: Display -> Colormap -> Color -> IO Color
    queryColor display colormap color =
            with color $ \ color_ptr -> do
            xQueryColor display colormap color_ptr
            peek color_ptr

    foreign import ccall unsafe "HsXlib.h XQueryColor"
            xQueryColor  :: Display -> Colormap -> Ptr Color -> IO ()

    -- | interface to the X11 library function @XQueryColors()@.
    queryColors :: Display -> Colormap -> [Color] -> IO [Color]
    queryColors display colormap colors =
            withArrayLen colors $ \ ncolors color_array -> do
            xQueryColors display colormap color_array (fromIntegral ncolors)
            peekArray ncolors color_array

    foreign import ccall unsafe "HsXlib.h XQueryColors"
            xQueryColors :: Display -> Colormap -> Ptr Color -> CInt -> IO ()

    -- | interface to the X11 library function @XInstallColormap()@.
    foreign import ccall unsafe "HsXlib.h XInstallColormap"
            installColormap     :: Display -> Colormap -> IO ()

    -- | interface to the X11 library function @XUninstallColormap()@.
    foreign import ccall unsafe "HsXlib.h XUninstallColormap"
            uninstallColormap   :: Display -> Colormap -> IO ()

    -- | interface to the X11 library function @XCopyColormapAndFree()@.
    foreign import ccall unsafe "HsXlib.h XCopyColormapAndFree"
            copyColormapAndFree :: Display -> Colormap -> IO Colormap

    -- | interface to the X11 library function @XCreateColormap()@.
    foreign import ccall unsafe "HsXlib.h XCreateColormap"
            createColormap      :: Display -> Window   -> Visual -> ColormapAlloc -> IO Colormap

    -- | interface to the X11 library function @XFreeColormap()@.
    foreign import ccall unsafe "HsXlib.h XFreeColormap"
            freeColormap        :: Display -> Colormap -> IO ()

    ----------------------------------------------------------------
    -- End
    ----------------------------------------------------------------