-- GENERATED by C->Haskell Compiler, version 0.13.4 (gtk2hs branch) "Bin IO", 13 Nov 2004 (Haskell)
-- Edit the ORIGNAL .chs file instead!


{-# LINE 1 "./Graphics/UI/Gtk/Gdk/Keys.chs" #-}
-- -*-haskell-*-
--  GIMP Toolkit (GTK) Keys
--
--  Author : Jens Petersen
--
--  Created: 24 May 2002
--
--  Copyright (C) 2002-2005 Jens Petersen
--
--  This library is free software; you can redistribute it and/or
--  modify it under the terms of the GNU Lesser General Public
--  License as published by the Free Software Foundation; either
--  version 2.1 of the License, or (at your option) any later version.
--
--  This library is distributed in the hope that it will be useful,
--  but WITHOUT ANY WARRANTY; without even the implied warranty of
--  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
--  Lesser General Public License for more details.
-- #prune

-- |
-- Maintainer  : gtk2hs-users@lists.sourceforge.net
-- Stability   : provisional
-- Portability : portable (depends on GHC)
--
-- A 'KeyVal' is a numeric value identifying a keyboard key. The defined
-- values can be found at <http://gitweb.freedesktop.org/?p=xorg/proto/x11proto.git;a=blob_plain;f=keysymdef.h>.
-- The names of the keys are the names of the macros without the prefix.
--
module Graphics.UI.Gtk.Gdk.Keys (
  KeyVal,
  keyName,
  keyFromName,
  keyToChar,

  keyvalName,
  keyvalFromName,
  keyvalToChar,
  ) where

import Control.Monad (liftM)

import System.Glib.FFI
import System.Glib.UTFString


{-# LINE 46 "./Graphics/UI/Gtk/Gdk/Keys.chs" #-}

-- | Key values are the codes which are sent whenever a key is pressed or
-- released.
--
type KeyVal = Word32

-- | Converts a key value into a symbolic name.
--
keyName :: KeyVal -> String
keyName k = unsafePerformIO $ keyvalName k

-- | Converts a key name to a key value.
--
keyFromName :: String -> KeyVal
keyFromName k = unsafePerformIO $ keyvalFromName k

-- | Convert from a Gdk key symbol to the corresponding Unicode character.
--
keyToChar :: 
    KeyVal          -- ^ @keyval@ - a Gdk key symbol
 -> Maybe Char -- ^ returns the corresponding unicode character, or
               -- Nothing if there is no corresponding character.
keyToChar k = unsafePerformIO $ keyvalToChar k

keyvalName :: KeyVal -> IO String
keyvalName keyval = do
  strPtr <- gdk_keyval_name (fromIntegral keyval)
  if strPtr==nullPtr then return "" else peekUTFString strPtr

keyvalFromName :: String -> IO KeyVal
keyvalFromName keyvalName =
  liftM fromIntegral $
  withCString keyvalName $ \keyvalNamePtr ->
  gdk_keyval_from_name
{-# LINE 80 "./Graphics/UI/Gtk/Gdk/Keys.chs" #-}
    keyvalNamePtr

keyvalToChar :: KeyVal -> IO (Maybe Char)
keyvalToChar keyval =
  gdk_keyval_to_unicode (fromIntegral keyval)
  >>= \code -> if code == 0 then return Nothing
                            else return $ Just $ toEnum $ fromIntegral code

foreign import ccall safe "gdk_keyval_name"
  gdk_keyval_name :: (CUInt -> (IO (Ptr CChar)))

foreign import ccall safe "gdk_keyval_from_name"
  gdk_keyval_from_name :: ((Ptr CChar) -> (IO CUInt))

foreign import ccall safe "gdk_keyval_to_unicode"
  gdk_keyval_to_unicode :: (CUInt -> (IO CUInt))