whim-0.1: Whim/Xlib.hs

{-# LANGUAGE ForeignFunctionInterface #-}
-- whim: a window manager
-- Copyright (C) 2006 Evan Martin <martine@danga.com>

-- | Extra functions that the built-in X11 module lacks.

module Whim.Xlib where

import Graphics.X11.Xlib
import Foreign

foreign import ccall "X11/Xlib.h XFree"
  x_free :: Ptr a -> IO ()
foreign import ccall "X11/Xlib.h XQueryTree"
  x_query_tree :: Display -> Window -> Ptr Window -> Ptr Window
               -> Ptr (Ptr Window) -> Ptr Int -> IO Int
queryTree :: Display -> Window -> IO [Window]
queryTree dpy win =
  with 0 $ \proot ->
  with 0 $ \pparent ->
  with nullPtr $ \ppchildren ->
  with 0 $ \pnchildren -> do
    throwIf (== 0) (const "XQueryTree failed") $
      x_query_tree dpy win proot pparent ppchildren pnchildren
    nchildren <- peek pnchildren
    pchildren <- peek ppchildren
    children <- peekArray nchildren pchildren
    x_free pchildren
    return children

type WindowAttributes = (Int, Int, Int, Int)
foreign import ccall "X11/Xlib.h XGetWindowAttributes"
  x_get_window_attributes :: Display -> Window -> Ptr Int -> IO Int
getWindowAttributes :: Display -> Window -> IO WindowAttributes
getWindowAttributes dpy win = do
  let structSize = 23
  allocaArray (structSize*4) $ \carr -> do
  throwIf (== 0) (const "XGetWindowAttributes failed") $
    x_get_window_attributes dpy win carr
  arr <- peekArray structSize carr
  let (x:y:w:h:_) = map fromIntegral arr
  return (x, y, w, h)

get_MapRequestEvent :: XEventPtr -> IO Window
get_MapRequestEvent ptr = peekElemOff (castPtr ptr) 5