Source code: org/eclipse/swt/widgets/Display.java

   /*******************************************************************************
    * Copyright (c) 2000, 2004 IBM Corporation and others.
    * All rights reserved. This program and the accompanying materials
    * are made available under the terms of the Common Public License v1.0
    * which accompanies this distribution, and is available at
    * http://www.eclipse.org/legal/cpl-v10.html
    * 
    * Contributors:
    *     IBM Corporation - initial API and implementation
   *******************************************************************************/
  package org.eclipse.swt.widgets;
  
  
  import org.eclipse.swt.*;
  import org.eclipse.swt.internal.*;
  import org.eclipse.swt.internal.gtk.*;
  import org.eclipse.swt.graphics.*;
  
  /**
   * Instances of this class are responsible for managing the
   * connection between SWT and the underlying operating
   * system. Their most important function is to implement
   * the SWT event loop in terms of the platform event model.
   * They also provide various methods for accessing information
   * about the operating system, and have overall control over
   * the operating system resources which SWT allocates.
   * <p>
   * Applications which are built with SWT will <em>almost always</em>
   * require only a single display. In particular, some platforms
   * which SWT supports will not allow more than one <em>active</em>
   * display. In other words, some platforms do not support
   * creating a new display if one already exists that has not been
   * sent the <code>dispose()</code> message.
   * <p>
   * In SWT, the thread which creates a <code>Display</code>
   * instance is distinguished as the <em>user-interface thread</em>
   * for that display.
   * </p>
   * The user-interface thread for a particular display has the
   * following special attributes:
   * <ul>
   * <li>
   * The event loop for that display must be run from the thread.
   * </li>
   * <li>
   * Some SWT API methods (notably, most of the public methods in
   * <code>Widget</code> and its subclasses), may only be called
   * from the thread. (To support multi-threaded user-interface
   * applications, class <code>Display</code> provides inter-thread
   * communication methods which allow threads other than the 
   * user-interface thread to request that it perform operations
   * on their behalf.)
   * </li>
   * <li>
   * The thread is not allowed to construct other 
   * <code>Display</code>s until that display has been disposed.
   * (Note that, this is in addition to the restriction mentioned
   * above concerning platform support for multiple displays. Thus,
   * the only way to have multiple simultaneously active displays,
   * even on platforms which support it, is to have multiple threads.)
   * </li>
   * </ul>
   * Enforcing these attributes allows SWT to be implemented directly
   * on the underlying operating system's event model. This has 
   * numerous benefits including smaller footprint, better use of 
   * resources, safer memory management, clearer program logic,
   * better performance, and fewer overall operating system threads
   * required. The down side however, is that care must be taken
   * (only) when constructing multi-threaded applications to use the
   * inter-thread communication mechanisms which this class provides
   * when required.
   * </p><p>
   * All SWT API methods which may only be called from the user-interface
   * thread are distinguished in their documentation by indicating that
   * they throw the "<code>ERROR_THREAD_INVALID_ACCESS</code>"
   * SWT exception.
   * </p>
   * <dl>
   * <dt><b>Styles:</b></dt>
   * <dd>(none)</dd>
   * <dt><b>Events:</b></dt>
   * <dd>Close, Dispose</dd>
   * </dl>
   * <p>
   * IMPORTANT: This class is <em>not</em> intended to be subclassed.
   * </p>
   * @see #syncExec
   * @see #asyncExec
   * @see #wake
   * @see #readAndDispatch
   * @see #sleep
   * @see Device#dispose
   */
  public class Display extends Device {
  
    /* Events Dispatching and Callback */
    boolean wake;
    int gdkEventCount;
    long /*int*/ [] gdkEvents;
   int [] dispatchEvents;
   Widget [] gdkEventWidgets;
   Event [] eventQueue;
   Callback eventCallback, filterCallback;
   GdkEventButton gdkEvent = new GdkEventButton ();
   long /*int*/ eventProc, filterProc, windowProc2, windowProc3, windowProc4, windowProc5;
   Callback windowCallback2, windowCallback3, windowCallback4, windowCallback5;
   EventTable eventTable, filterTable;
   static String APP_NAME = "SWT";
   static final String DISPATCH_EVENT_KEY = "org.eclipse.swt.internal.gtk.dispatchEvent";
 
   /* Widget Table */
   int freeSlot;
   int [] indexTable;
   Widget [] widgetTable;
   final static int GROW_SIZE = 1024;
   static final int SWT_OBJECT_INDEX;
   static {
     byte [] buffer = Converter.wcsToMbcs (null, "SWT_OBJECT_INDEX", true);
     SWT_OBJECT_INDEX = OS.g_quark_from_string (buffer);
   }
     
   /* Input method resources */
   Control imControl;
   long /*int*/ preeditWindow, preeditLabel;
 
   /* Sync/Async Widget Communication */
   Synchronizer synchronizer = new Synchronizer (this);
   Thread thread;
 
   /* Display Shutdown */
   Runnable [] disposeList;
   
   /* System Tray */
   Tray tray;
   
   /* Timers */
   int [] timerIds;
   Runnable [] timerList;
   Callback timerCallback;
   long /*int*/ timerProc;
   Callback windowTimerCallback;
   long /*int*/ windowTimerProc;
   
   /* Caret */
   Caret currentCaret;
   Callback caretCallback;
   int caretId;
   long /*int*/ caretProc;
   
   /* Mnemonics */
   Control mnemonicControl;
 
   /* Mouse hover */
   int mouseHoverId;
   long /*int*/ mouseHoverHandle, mouseHoverProc;
   Callback mouseHoverCallback;
   
   /* Menu position callback */
   long /*int*/ menuPositionProc;
   Callback menuPositionCallback;
 
   /* Shell map callback */
   long /*int*/ shellMapProc;
   Callback shellMapCallback;
   
   /* GtkTreeView callbacks */
   int[] treeSelection;
   int treeSelectionLength;
   long /*int*/ treeSelectionProc;
   Callback treeSelectionCallback;
   long /*int*/ textCellDataProc;
   Callback textCellDataCallback;
   long /*int*/ pixbufCellDataProc;
   Callback pixbufCellDataCallback;
   
   /* Flush exposes */
   long /*int*/ checkIfEventProc;
   Callback checkIfEventCallback;
   long /*int*/ flushWindow;
   boolean flushAll;
   GdkRectangle flushRect = new GdkRectangle ();
   XExposeEvent exposeEvent = new XExposeEvent ();
   XVisibilityEvent visibilityEvent = new XVisibilityEvent ();
   long /*int*/ [] flushData = new long /*int*/ [1];
 
   /* Drag Detect */
   int dragStartX,dragStartY;
   boolean dragging;
   
   /* Fonts */
   long /*int*/ defaultFont;
 
   /* System Images */
   long /*int*/ errorPixmap, infoPixmap, questionPixmap, warningPixmap;
   long /*int*/ errorMask, infoMask, questionMask, warningMask;
   
   /* System Cursors */
   Cursor [] cursors = new Cursor [SWT.CURSOR_HAND + 1];
 
   /* Colors */
   GdkColor COLOR_WIDGET_DARK_SHADOW, COLOR_WIDGET_NORMAL_SHADOW, COLOR_WIDGET_LIGHT_SHADOW;
   GdkColor COLOR_WIDGET_HIGHLIGHT_SHADOW, COLOR_WIDGET_BACKGROUND, COLOR_WIDGET_FOREGROUND, COLOR_WIDGET_BORDER;
   GdkColor COLOR_LIST_FOREGROUND, COLOR_LIST_BACKGROUND, COLOR_LIST_SELECTION, COLOR_LIST_SELECTION_TEXT;
   GdkColor COLOR_TEXT_FOREGROUND, COLOR_TEXT_BACKGROUND, COLOR_INFO_BACKGROUND, COLOR_INFO_FOREGROUND;
   GdkColor COLOR_TITLE_FOREGROUND, COLOR_TITLE_BACKGROUND, COLOR_TITLE_BACKGROUND_GRADIENT;
   GdkColor COLOR_TITLE_INACTIVE_FOREGROUND, COLOR_TITLE_INACTIVE_BACKGROUND, COLOR_TITLE_INACTIVE_BACKGROUND_GRADIENT;
 
   /* Popup Menus */
   Menu [] popups;
   int popupTime;
   
   /* Key Mappings */
   static final int [] [] KeyTable = {
     
     /* Keyboard and Mouse Masks */
     {OS.GDK_Alt_L,    SWT.ALT},
     {OS.GDK_Alt_R,    SWT.ALT},
     {OS.GDK_Meta_L,  SWT.ALT},
     {OS.GDK_Meta_R,  SWT.ALT},
     {OS.GDK_Shift_L,    SWT.SHIFT},
     {OS.GDK_Shift_R,    SWT.SHIFT},
     {OS.GDK_Control_L,  SWT.CONTROL},
     {OS.GDK_Control_R,  SWT.CONTROL},
 //    {OS.GDK_????,    SWT.COMMAND},
 //    {OS.GDK_????,    SWT.COMMAND},
     
     /* Non-Numeric Keypad Keys */
     {OS.GDK_Up,            SWT.ARROW_UP},
     {OS.GDK_KP_Up,          SWT.ARROW_UP},
     {OS.GDK_Down,          SWT.ARROW_DOWN},
     {OS.GDK_KP_Down,      SWT.ARROW_DOWN},
     {OS.GDK_Left,            SWT.ARROW_LEFT},
     {OS.GDK_KP_Left,        SWT.ARROW_LEFT},
     {OS.GDK_Right,          SWT.ARROW_RIGHT},
     {OS.GDK_KP_Right,        SWT.ARROW_RIGHT},
     {OS.GDK_Page_Up,        SWT.PAGE_UP},
     {OS.GDK_KP_Page_Up,    SWT.PAGE_UP},
     {OS.GDK_Page_Down,      SWT.PAGE_DOWN},
     {OS.GDK_KP_Page_Down,  SWT.PAGE_DOWN},
     {OS.GDK_Home,          SWT.HOME},
     {OS.GDK_KP_Home,      SWT.HOME},
     {OS.GDK_End,            SWT.END},
     {OS.GDK_KP_End,        SWT.END},
     {OS.GDK_Insert,          SWT.INSERT},
     {OS.GDK_KP_Insert,      SWT.INSERT},
     
     /* Virtual and Ascii Keys */
     {OS.GDK_BackSpace,    SWT.BS},
     {OS.GDK_Return,        SWT.CR},
     {OS.GDK_Delete,        SWT.DEL},
     {OS.GDK_KP_Delete,    SWT.DEL},
     {OS.GDK_Escape,      SWT.ESC},
     {OS.GDK_Linefeed,      SWT.LF},
     {OS.GDK_Tab,          SWT.TAB},
     {OS.GDK_ISO_Left_Tab,   SWT.TAB},
   
     /* Functions Keys */
     {OS.GDK_F1,    SWT.F1},
     {OS.GDK_F2,    SWT.F2},
     {OS.GDK_F3,    SWT.F3},
     {OS.GDK_F4,    SWT.F4},
     {OS.GDK_F5,    SWT.F5},
     {OS.GDK_F6,    SWT.F6},
     {OS.GDK_F7,    SWT.F7},
     {OS.GDK_F8,    SWT.F8},
     {OS.GDK_F9,    SWT.F9},
     {OS.GDK_F10,    SWT.F10},
     {OS.GDK_F11,    SWT.F11},
     {OS.GDK_F12,    SWT.F12},
     {OS.GDK_F13,    SWT.F13},
     {OS.GDK_F14,    SWT.F14},
     {OS.GDK_F15,    SWT.F15},
     
     /* Numeric Keypad Keys */
     {OS.GDK_KP_Multiply,    SWT.KEYPAD_MULTIPLY},
     {OS.GDK_KP_Add,      SWT.KEYPAD_ADD},
     {OS.GDK_KP_Enter,      SWT.KEYPAD_CR},
     {OS.GDK_KP_Subtract,  SWT.KEYPAD_SUBTRACT},
     {OS.GDK_KP_Decimal,  SWT.KEYPAD_DECIMAL},
     {OS.GDK_KP_Divide,    SWT.KEYPAD_DIVIDE},
     {OS.GDK_KP_0,      SWT.KEYPAD_0},
     {OS.GDK_KP_1,      SWT.KEYPAD_1},
     {OS.GDK_KP_2,      SWT.KEYPAD_2},
     {OS.GDK_KP_3,      SWT.KEYPAD_3},
     {OS.GDK_KP_4,      SWT.KEYPAD_4},
     {OS.GDK_KP_5,      SWT.KEYPAD_5},
     {OS.GDK_KP_6,      SWT.KEYPAD_6},
     {OS.GDK_KP_7,      SWT.KEYPAD_7},
     {OS.GDK_KP_8,      SWT.KEYPAD_8},
     {OS.GDK_KP_9,      SWT.KEYPAD_9},
     {OS.GDK_KP_Equal,  SWT.KEYPAD_EQUAL},
 
     /* Other keys */
     {OS.GDK_Caps_Lock,    SWT.CAPS_LOCK},
     {OS.GDK_Num_Lock,    SWT.NUM_LOCK},
     {OS.GDK_Scroll_Lock,    SWT.SCROLL_LOCK},
     {OS.GDK_Pause,        SWT.PAUSE},
     {OS.GDK_Break,        SWT.BREAK},
     {OS.GDK_Print,          SWT.PRINT_SCREEN},
     {OS.GDK_Help,          SWT.HELP},
     
   };
 
   /* Multiple Displays. */
   static Display Default;
   static Display [] Displays = new Display [4];
 
   /* Package name */
   static final String PACKAGE_PREFIX = "org.eclipse.swt.widgets.";
   /* This code is intentionally commented.
    * ".class" can not be used on CLDC.
    */
   /*static {
     String name = Display.class.getName ();
     int index = name.lastIndexOf ('.');
     PACKAGE_NAME = name.substring (0, index + 1);
   }*/
 
   /*
   * In order to support CLDC, .class cannot be used because
   * it does not compile on some Java compilers when they are
   * targeted for CLDC.  Use Class.forName() instead.
   */
   static final Class OS_LOCK;
   static {
     Class lock = null;
     try {
       lock = Class.forName ("org.eclipse.swt.internal.gtk.OS");
     } catch (Throwable th) {
     }
     OS_LOCK = lock;
   }
   
   /* #define in gdkevents.h */
   static final int DOUBLE_CLICK_TIME = 250;
 
   /* GTK Version */
   static final int MAJOR = 2;
   static final int MINOR = 0;
   static final int MICRO = 6;
 
   /* Display Data */
   Object data;
   String [] keys;
   Object [] values;
   
   /* Initial Guesses for Shell Trimmings. */
   int borderTrimWidth = 4, borderTrimHeight = 4;
   int resizeTrimWidth = 6, resizeTrimHeight = 6;
   int titleBorderTrimWidth = 5, titleBorderTrimHeight = 28;
   int titleResizeTrimWidth = 6, titleResizeTrimHeight = 29;
   int titleTrimWidth = 0, titleTrimHeight = 23;
   
   /*
   * TEMPORARY CODE.  Install the runnable that
   * gets the current display. This code will
   * be removed in the future.
   */
   static {
     DeviceFinder = new Runnable () {
       public void run () {
         Device device = getCurrent ();
         if (device == null) {
           device = getDefault ();
         }
         setDevice (device);
       }
     };
   }
 
 /*
 * TEMPORARY CODE.
 */
 static void setDevice (Device device) {
   CurrentDevice = device;
 }
 
 /**
  * Constructs a new instance of this class.
  * <p>
  * Note: The resulting display is marked as the <em>current</em>
  * display. If this is the first display which has been 
  * constructed since the application started, it is also
  * marked as the <em>default</em> display.
  * </p>
  *
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
  *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
  * </ul>
  *
  * @see #getCurrent
  * @see #getDefault
  * @see Widget#checkSubclass
  * @see Shell
  */
 public Display () {
   this (null);
 }
 
 public Display (DeviceData data) {
   super (data);
 }
 
 /**
  * Adds the listener to the collection of listeners who will
  * be notifed when an event of the given type occurs anywhere
  * in this display. When the event does occur, the listener is
  * notified by sending it the <code>handleEvent()</code> message.
  *
  * @param eventType the type of event to listen for
  * @param listener the listener which should be notified when the event occurs
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  *
  * @see Listener
  * @see #removeFilter
  * @see #removeListener
  * 
  * @since 3.0 
  */
 public void addFilter (int eventType, Listener listener) {
   checkDevice ();
   if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
   if (filterTable == null) filterTable = new EventTable ();
   filterTable.hook (eventType, listener);
 }
 
 void addGdkEvent (long /*int*/ event) {
   if (gdkEvents == null) {
     gdkEvents = new long /*int*/ [4];
     gdkEventWidgets = new Widget [4];
     gdkEventCount = 0;
   }
   if (gdkEventCount == gdkEvents.length) {
     long /*int*/ [] newEvents = new long /*int*/ [gdkEventCount + 4];
     System.arraycopy (gdkEvents, 0, newEvents, 0, gdkEventCount);
     gdkEvents = newEvents;
     Widget [] newWidgets = new Widget [gdkEventCount + 4];
     System.arraycopy (gdkEventWidgets, 0, newWidgets, 0, gdkEventCount);
     gdkEventWidgets = newWidgets;
   }
   Widget widget = null;
   long /*int*/ handle = OS.gtk_get_event_widget (event);
   if (handle != 0) {
     do {
       widget = getWidget (handle);
     } while (widget == null && (handle = OS.gtk_widget_get_parent (handle)) != 0);
   }
   gdkEvents [gdkEventCount] = event;
   gdkEventWidgets [gdkEventCount] = widget;
   gdkEventCount++;
 }
 
 /**
  * Adds the listener to the collection of listeners who will
  * be notifed when an event of the given type occurs. When the
  * event does occur in the display, the listener is notified by
  * sending it the <code>handleEvent()</code> message.
  *
  * @param eventType the type of event to listen for
  * @param listener the listener which should be notified when the event occurs
  *
  * @exception IllegalArgumentException <ul>
  *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
  * </ul>
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  *
  * @see Listener
  * @see #removeListener
  * 
  * @since 2.0 
  */
 public void addListener (int eventType, Listener listener) {
   checkDevice ();
   if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
   if (eventTable == null) eventTable = new EventTable ();
   eventTable.hook (eventType, listener);
 }
 
 void addMouseHoverTimeout (long /*int*/ handle) {
   if (mouseHoverId != 0) OS.gtk_timeout_remove (mouseHoverId);
   mouseHoverId = OS.gtk_timeout_add (400, mouseHoverProc, handle);
   mouseHoverHandle = handle;
 }
 
 void addPopup (Menu menu) {
   if (popups == null) popups = new Menu [4];
   int length = popups.length;
   for (int i=0; i<length; i++) {
     if (popups [i] == menu) return;
   }
   int index = 0;
   while (index < length) {
     if (popups [index] == null) break;
     index++;
   }
   if (index == length) {
     Menu [] newPopups = new Menu [length + 4];
     System.arraycopy (popups, 0, newPopups, 0, length);
     popups = newPopups;
   }
   popups [index] = menu;
 }
 
 void addWidget (long /*int*/ handle, Widget widget) {
   if (handle == 0) return;
   if (freeSlot == -1) {
     int length = (freeSlot = indexTable.length) + GROW_SIZE;
     int[] newIndexTable = new int[length];
     Widget[] newWidgetTable = new Widget [length];
     System.arraycopy (indexTable, 0, newIndexTable, 0, freeSlot);
     System.arraycopy (widgetTable, 0, newWidgetTable, 0, freeSlot);
     for (int i = freeSlot; i < length - 1; i++) {
       newIndexTable[i] = i + 1;
     }
     newIndexTable[length - 1] = -1;
     indexTable = newIndexTable;
     widgetTable = newWidgetTable;
   }
   int index = freeSlot + 1;
   OS.g_object_set_qdata (handle, SWT_OBJECT_INDEX, index);
   int oldSlot = freeSlot;
   freeSlot = indexTable[oldSlot];
   indexTable [oldSlot] = -2;
   widgetTable [oldSlot] = widget;
 }
 
 /**
  * Causes the <code>run()</code> method of the runnable to
  * be invoked by the user-interface thread at the next 
  * reasonable opportunity. The caller of this method continues 
  * to run in parallel, and is not notified when the
  * runnable has completed.
  *
  * @param runnable code to run on the user-interface thread.
  *
  * @exception SWTException <ul>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  * 
  * @see #syncExec
  */
 public void asyncExec (Runnable runnable) {
   if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
   synchronizer.asyncExec (runnable);
 }
 
 /**
  * Causes the system hardware to emit a short sound
  * (if it supports this capability).
  * 
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  */
 public void beep () {
   if (!isValidThread ()) error (SWT.ERROR_THREAD_INVALID_ACCESS);
   OS.gdk_beep();
   OS.gdk_flush();
 }
 
 protected void checkDevice () {
   if (thread == null) error (SWT.ERROR_WIDGET_DISPOSED);
   if (thread != Thread.currentThread ()) error (SWT.ERROR_THREAD_INVALID_ACCESS);
   if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
 }
 
 static synchronized void checkDisplay (Thread thread) {
   for (int i=0; i<Displays.length; i++) {
     if (Displays [i] != null && Displays [i].thread == thread) {
       SWT.error (SWT.ERROR_THREAD_INVALID_ACCESS);
     }
   }
 }
 
 long /*int*/ checkIfEventProc (long /*int*/ display, long /*int*/ xEvent, long /*int*/ userData) {
   OS.memmove (exposeEvent, xEvent, XExposeEvent.sizeof);
   switch (exposeEvent.type) {
     case OS.VisibilityNotify:
     case OS.Expose:
     case OS.GraphicsExpose:
       break;
     default:
       return 0;
   }
   long /*int*/ window = OS.gdk_window_lookup (exposeEvent.window);
   if (window == 0) return 0;
   if (flushWindow != 0) {
     if (flushAll) {
       long /*int*/ tempWindow = window;
       do {
         if (tempWindow == flushWindow) break;
       } while ((tempWindow = OS.gdk_window_get_parent (tempWindow)) != 0);
       if (tempWindow != flushWindow) return 0;
     } else {
       if (window != flushWindow) return 0;
     }
   }
   switch (exposeEvent.type) {
     case OS.Expose:
     case OS.GraphicsExpose: {
       flushRect.x = exposeEvent.x;
       flushRect.y = exposeEvent.y;
       flushRect.width = exposeEvent.width;
       flushRect.height = exposeEvent.height;
       OS.gdk_window_invalidate_rect (window, flushRect, true);
       exposeEvent.type = -1;
       OS.memmove (xEvent, exposeEvent, XExposeEvent.sizeof);
       break;
     }
     case OS.VisibilityNotify: {
       OS.memmove (visibilityEvent, xEvent, XVisibilityEvent.sizeof);
       OS.gdk_window_get_user_data (window, flushData);
       long /*int*/ handle = flushData [0];
       Widget widget = handle != 0 ? getWidget (handle) : null;
       if (widget != null && widget instanceof Control) {
         Control control = (Control) widget;
         if (window == control.paintWindow ()) {
           if (visibilityEvent.state == OS.VisibilityFullyObscured) {
             control.state |= Widget.OBSCURED;
           } else {
             control.state &= ~Widget.OBSCURED;
           }
         }
       }
       break;
     }
   }
   return 0;
 }
 
 /**
  * Checks that this class can be subclassed.
  * <p>
  * IMPORTANT: See the comment in <code>Widget.checkSubclass()</code>.
  * </p>
  *
  * @exception SWTException <ul>
  *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
  * </ul>
  *
  * @see Widget#checkSubclass
  */
 protected void checkSubclass () {
   if (!isValidClass (getClass ())) error (SWT.ERROR_INVALID_SUBCLASS);
 }
 
 /**
  * Requests that the connection between SWT and the underlying
  * operating system be closed.
  *
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  *
  * @see Device#dispose
  * 
  * @since 2.0
  */
 public void close () {
   checkDevice ();
   Event event = new Event ();
   sendEvent (SWT.Close, event);
   if (event.doit) dispose ();
 }
 
 /**
  * Creates the device in the operating system.  If the device
  * does not have a handle, this method may do nothing depending
  * on the device.
  * <p>
  * This method is called before <code>init</code>.
  * </p>
  *
  * @param data the DeviceData which describes the receiver
  *
  * @see #init
  */
 protected void create (DeviceData data) {
   checkSubclass ();
   checkDisplay(thread = Thread.currentThread ());
   createDisplay (data);
   register ();
   if (Default == null) Default = this;
 }
 
 synchronized void createDisplay (DeviceData data) {
   /*
   * This code is intentionally commented.
   */
 //  if (!OS.g_thread_supported ()) {
 //    OS.g_thread_init (0);
 //    OS.gdk_threads_init ();
 //  }
   OS.gtk_set_locale();
   if (!OS.gtk_init_check (new long /*int*/ [] {0}, null)) {
     SWT.error (SWT.ERROR_NO_HANDLES);
   }
   OS.gtk_widget_set_default_direction (OS.GTK_TEXT_DIR_LTR);
   OS.gdk_rgb_init ();
   long /*int*/ ptr = OS.gtk_check_version (MAJOR, MINOR, MICRO);
   if (ptr != 0) {
     int length = OS.strlen (ptr);
     byte [] buffer = new byte [length];
     OS.memmove (buffer, ptr, length);
     System.out.println ("***WARNING: " + new String (Converter.mbcsToWcs (null, buffer)));
     System.out.println ("***WARNING: SWT requires GTK " + MAJOR+ "." + MINOR + "." + MICRO);
     int major = OS.gtk_major_version (), minor = OS.gtk_minor_version (), micro = OS.gtk_micro_version ();
     System.out.println ("***WARNING: Detected: " + major + "." + minor + "." + micro);
   }
   byte [] buffer = Converter.wcsToMbcs (null, APP_NAME, true);
   OS.gdk_set_program_class (buffer);
   byte [] flatStyle = Converter.wcsToMbcs (null, "style \"swt-flat\" { GtkToolbar::shadow-type = none } widget \"*swt-toolbar-flat*\" style : highest \"swt-flat\"", true);
   OS.gtk_rc_parse_string (flatStyle);
 
   /* Initialize the event callback */
   eventCallback = new Callback (this, "eventProc", 2);
   eventProc = eventCallback.getAddress ();
   if (eventProc == 0) SWT.error (SWT.ERROR_NO_MORE_CALLBACKS);
   OS.gdk_event_handler_set (eventProc, 0, 0);
 }
 
 long /*int*/[] createImage (String name) {
   long /*int*/ style = OS.gtk_widget_get_default_style ();
   byte[] buffer = Converter.wcsToMbcs (null, name, true);
   long /*int*/ pixbuf = OS.gtk_icon_set_render_icon (
     OS.gtk_icon_factory_lookup_default (buffer), style,
     OS.GTK_TEXT_DIR_NONE, OS.GTK_STATE_NORMAL, -1, 0, 0);
   if (pixbuf == 0) return null;
   long /*int*/[] pixmap_return = new long /*int*/[1];
   long /*int*/[] mask_return = new long /*int*/[1];
   OS.gdk_pixbuf_render_pixmap_and_mask (pixbuf, pixmap_return, mask_return, 128);
   OS.g_object_unref (pixbuf);
   return new long /*int*/[] {pixmap_return [0], mask_return [0]};
 }
 
 synchronized void deregister () {
   for (int i=0; i<Displays.length; i++) {
     if (this == Displays [i]) Displays [i] = null;
   }
 }
 
 /**
  * Destroys the device in the operating system and releases
  * the device's handle.  If the device does not have a handle,
  * this method may do nothing depending on the device.
  * <p>
  * This method is called after <code>release</code>.
  * </p>
  * @see #dispose
  * @see #release
  */
 protected void destroy () {
   if (this == Default) Default = null;
   deregister ();
   destroyDisplay ();
 }
 
 void destroyDisplay () {
 }
 
 /**
  * Returns the display which the given thread is the
  * user-interface thread for, or null if the given thread
  * is not a user-interface thread for any display.
  *
  * @param thread the user-interface thread
  * @return the display for the given thread
  */
 public static synchronized Display findDisplay (Thread thread) {
   for (int i=0; i<Displays.length; i++) {
     Display display = Displays [i];
     if (display != null && display.thread == thread) {
       return display;
     }
   }
   return null;
 }
 
 /**
  * Causes the <code>run()</code> method of the runnable to
  * be invoked by the user-interface thread just before the
  * receiver is disposed.
  *
  * @param runnable code to run at dispose time.
  * 
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  */
 public void disposeExec (Runnable runnable) {
   checkDevice ();
   if (disposeList == null) disposeList = new Runnable [4];
   for (int i=0; i<disposeList.length; i++) {
     if (disposeList [i] == null) {
       disposeList [i] = runnable;
       return;
     }
   }
   Runnable [] newDisposeList = new Runnable [disposeList.length + 4];
   System.arraycopy (disposeList, 0, newDisposeList, 0, disposeList.length);
   newDisposeList [disposeList.length] = runnable;
   disposeList = newDisposeList;
 }
 
 /**
  * Does whatever display specific cleanup is required, and then
  * uses the code in <code>SWTError.error</code> to handle the error.
  *
  * @param code the descriptive error code
  *
  * @see SWTError#error
  */
 void error (int code) {
   SWT.error (code);
 }
 
 long /*int*/ eventProc (long /*int*/ event, long /*int*/ data) {
   OS.memmove (gdkEvent, event, GdkEventButton.sizeof);
   boolean dispatch = true;
   if (dispatchEvents != null) {
     dispatch = false;
     for (int i = 0; i < dispatchEvents.length; i++) {
       if (gdkEvent.type == dispatchEvents [i]) {
         dispatch = true;
         break;
       }
     }
   }
   if (!dispatch) {
     addGdkEvent (OS.gdk_event_copy (event));
     return 0;
   }
   Control control = null;
   long /*int*/ window = 0;
   switch (gdkEvent.type) {
     case OS.GDK_ENTER_NOTIFY:
     case OS.GDK_LEAVE_NOTIFY:
     case OS.GDK_BUTTON_PRESS:
     case OS.GDK_2BUTTON_PRESS: 
     case OS.GDK_3BUTTON_PRESS:
     case OS.GDK_BUTTON_RELEASE: 
     case OS.GDK_MOTION_NOTIFY:  {
       window = gdkEvent.window;
       long /*int*/ [] user_data = new long /*int*/ [1];
       do {
         OS.gdk_window_get_user_data (window, user_data);
         long /*int*/ handle = user_data [0];
         if (handle != 0) {
           Widget widget = getWidget (handle);
           if (widget != null && widget instanceof Control) {
             control = (Control) widget;
             break;
           }
         }
       } while ((window = OS.gdk_window_get_parent (window)) != 0);
     }
   }
   Shell shell = null;
   if (control != null ) {
     shell = control.getShell ();
     if ((shell.style & SWT.ON_TOP) != 0) {
       OS.gtk_grab_add (shell.shellHandle);
     }
   }
   OS.gtk_main_do_event (event);
   if (dispatchEvents == null) putGdkEvents ();
   if (control != null ) {
     if (shell != null && !shell.isDisposed () && (shell.style & SWT.ON_TOP) != 0) {
       OS.gtk_grab_remove (shell.shellHandle);
     }
   }
   return 0;
 }
 
 /**
  * Given the operating system handle for a widget, returns
  * the instance of the <code>Widget</code> subclass which
  * represents it in the currently running application, if
  * such exists, or null if no matching widget can be found.
  *
  * @param handle the handle for the widget
  * @return the SWT widget that the handle represents
  *
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  */
 public Widget findWidget (long /*int*/ handle) {
   checkDevice ();
   return getWidget (handle);
 }
 
 void flushExposes (long /*int*/ window, boolean all) {
   OS.gdk_flush ();
   OS.gdk_flush ();
   if (OS.GDK_WINDOWING_X11 ()) {
     this.flushWindow = window;
     this.flushAll = all;
     long /*int*/ xDisplay = OS.GDK_DISPLAY ();
     long /*int*/ xEvent = OS.g_malloc (XEvent.sizeof);
     OS.XCheckIfEvent (xDisplay, xEvent, checkIfEventProc, 0);
     OS.g_free (xEvent);
     this.flushWindow = 0;
   }
 }
 
 /**
  * Returns the currently active <code>Shell</code>, or null
  * if no shell belonging to the currently running application
  * is active.
  *
  * @return the active shell or null
  *
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  */
 public Shell getActiveShell () {
   checkDevice ();
   Shell [] shells = getShells ();
   for (int i=0; i<shells.length; i++) {
      if (shells [i].hasFocus) return shells [i];
   }
   return null;
 }
 
 /**
  * Returns a rectangle describing the receiver's size and location.
  *
  * @return the bounding rectangle
  *
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  */
 public Rectangle getBounds () {
   checkDevice ();
   return new Rectangle (0, 0, OS.gdk_screen_width (), OS.gdk_screen_height ());
 }
 
 /**
  * Returns the display which the currently running thread is
  * the user-interface thread for, or null if the currently
  * running thread is not a user-interface thread for any display.
  *
  * @return the current display
  */
 public static synchronized Display getCurrent () {
   Thread current = Thread.currentThread ();
   for (int i=0; i<Displays.length; i++) {
     Display display = Displays [i];
     if (display != null && display.thread == current) return display;
   }
   return null;
 }
 
 /**
  * Returns the control which the on-screen pointer is currently
  * over top of, or null if it is not currently over one of the
  * controls built by the currently running application.
  *
  * @return the control under the cursor
  *
  * @exception SWTException <ul>
  *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
  *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
  * </ul>
  */
 public Control getCursorControl () {
   checkDevice();
   int[] x = new int[1], y = new int[1];
   long /*int*/ window = OS.gdk_window_at_pointer (x,y);
   if (window == 0) return null;
   long /*int*/ [] user_data = new long /*int*/ [1];
   OS.gdk_window_get_user_data (window, user_data);
   long /*int*/ handle = user_data [0];
   if (handle == 0) return null;
   do {
     Widget widget = getWidget (handle);
     if (widget != null && widget instanceof Control) {
       Control control = (Control) widget;
       if (control.isEnabled ()) return control;
    }
  } while ((handle = OS.gtk_widget_get_parent (handle)) != 0);
  return null;
}

boolean filterEvent (Event event) {
  if (filterTable != null) filterTable.sendEvent (event);
  return false;
}

boolean filters (int eventType) {
  if (filterTable == null) return false;
  return filterTable.hooks (eventType);
}

long /*int*/ filterProc (long /*int*/ xEvent, long /*int*/ gdkEvent, long /*int*/ data) {
  Widget widget = getWidget (data);
  if (widget == null) return 0;
  return widget.filterProc (xEvent, gdkEvent, data);
}

/**
 * Returns the location of the on-screen pointer relative
 * to the top left corner of the screen.
 *
 * @return the cursor location
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Point getCursorLocation () {
  checkDevice ();
  int [] x = new int [1], y = new int [1];
  OS.gdk_window_get_pointer (0, x, y, null);
  return new Point (x [0], y [0]);
}

/**
 * Returns an array containing the recommended cursor sizes.
 *
 * @return the array of cursor sizes
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 3.0
 */
public Point [] getCursorSizes () {
  checkDevice ();
  return new Point [] {new Point (16, 16), new Point (32, 32)}; 
}

/**
 * Returns the application defined property of the receiver
 * with the specified name, or null if it has not been set.
 * <p>
 * Applications may have associated arbitrary objects with the
 * receiver in this fashion. If the objects stored in the
 * properties need to be notified when the display is disposed
 * of, it is the application's responsibility provide a
 * <code>disposeExec()</code> handler which does so.
 * </p>
 *
 * @param key the name of the property
 * @return the value of the property or null if it has not been set
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the key is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #setData
 * @see #disposeExec
 */
public Object getData (String key) {
  checkDevice ();
  if (key == null) error (SWT.ERROR_NULL_ARGUMENT);
  if (key.equals (DISPATCH_EVENT_KEY)) {
    return dispatchEvents;
  }
  if (keys == null) return null;
  for (int i=0; i<keys.length; i++) {
    if (keys [i].equals (key)) return values [i];
  }
  return null;
}

/**
 * Returns the application defined, display specific data
 * associated with the receiver, or null if it has not been
 * set. The <em>display specific data</em> is a single,
 * unnamed field that is stored with every display. 
 * <p>
 * Applications may put arbitrary objects in this field. If
 * the object stored in the display specific data needs to
 * be notified when the display is disposed of, it is the
 * application's responsibility provide a
 * <code>disposeExec()</code> handler which does so.
 * </p>
 *
 * @return the display specific data
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #setData
 * @see #disposeExec
 */
public Object getData () {
  checkDevice ();
  return data;
}

/**
 * Returns a point whose x coordinate is the horizontal
 * dots per inch of the display, and whose y coordinate
 * is the vertical dots per inch of the display.
 *
 * @return the horizontal and vertical DPI
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 */
public Point getDPI () {
  checkDevice ();
  int widthMM = OS.gdk_screen_width_mm ();
  int width = OS.gdk_screen_width ();
  int dpi = Compatibility.round (254 * width, widthMM * 10);
  return new Point (dpi, dpi);
}

/**
 * Returns the default display. One is created (making the
 * thread that invokes this method its user-interface thread)
 * if it did not already exist.
 *
 * @return the default display
 */
public static synchronized Display getDefault () {
  if (Default == null) Default = new Display ();
  return Default;
}

static boolean isValidClass (Class clazz) {
  String name = clazz.getName ();
  int index = name.lastIndexOf ('.');
  return name.substring (0, index + 1).equals (PACKAGE_PREFIX);
}

/**
 * Returns the button dismissal alignment, one of <code>LEFT</code> or <code>RIGHT</code>.
 * The button dismissal alignment is the ordering that should be used when positioning the
 * default dismissal button for a dialog.  For example, in a dialog that contains an OK and
 * CANCEL button, on platforms where the button dismissal alignment is <code>LEFT</code>, the
 * button ordering should be OK/CANCEL.  When button dismissal alignment is <code>RIGHT</code>,
 * the button ordering should be CANCEL/OK.
 *
 * @return the button dismissal order
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.1
 */
public int getDismissalAlignment () {
  checkDevice ();
  return SWT.RIGHT;
}

/**
 * Returns the longest duration, in milliseconds, between
 * two mouse button clicks that will be considered a
 * <em>double click</em> by the underlying operating system.
 *
 * @return the double click time
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getDoubleClickTime () {
  checkDevice ();
  return DOUBLE_CLICK_TIME;
}

/**
 * Returns the control which currently has keyboard focus,
 * or null if keyboard events are not currently going to
 * any of the controls built by the currently running
 * application.
 *
 * @return the control under the cursor
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Control getFocusControl () {
  checkDevice ();
  Shell shell = getActiveShell ();
  if (shell == null) return null;
  long /*int*/ shellHandle = shell.shellHandle;
  long /*int*/ handle = OS.gtk_window_get_focus (shellHandle);
  if (handle == 0) return null;
  do {
    Widget widget = getWidget (handle);
    if (widget != null && widget instanceof Control) {
      Control control = (Control) widget;
      return control.isEnabled () ? control : null;
    }
  } while ((handle = OS.gtk_widget_get_parent (handle)) != 0);
  return null;
}

/**
 * Returns true when the high contrast mode is enabled.
 * Otherwise, false is returned.
 * <p>
 * Note: This operation is a hint and is not supported on
 * platforms that do not have this concept.
 * </p>
 *
 * @return the high contrast mode
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 3.0
 */
public boolean getHighContrast () {
  checkDevice ();
  return false;
}

public int getDepth () {
  checkDevice ();
  GdkVisual visual = new GdkVisual ();
  OS.memmove (visual, OS.gdk_visual_get_system());
  return visual.depth;
}

/**
 * Returns the maximum allowed depth of icons on this display.
 * On some platforms, this may be different than the actual
 * depth of the display.
 *
 * @return the maximum icon depth
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public int getIconDepth () {
  checkDevice ();
  return getDepth ();
}

/**
 * Returns an array containing the recommended icon sizes.
 *
 * @return the array of icon sizes
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see Decorations#setImages(Image[])
 * 
 * @since 3.0
 */
public Point [] getIconSizes () {
  checkDevice ();
  return new Point [] {new Point (16, 16), new Point (32, 32)}; 
}

int getLastEventTime () {
  return OS.gtk_get_current_event_time ();
}

int getMessageCount () {
  return synchronizer.getMessageCount ();
}

/**
 * Returns an array of monitors attached to the device.
 * 
 * @return the array of monitors
 * 
 * @since 3.0
 */
public Monitor [] getMonitors () {
  checkDevice ();
  Monitor [] monitors = null;
  long /*int*/ screen = OS.gdk_screen_get_default ();
  if (screen != 0) {
    int monitorCount = OS.gdk_screen_get_n_monitors (screen);
    if (monitorCount > 0) {
      monitors = new Monitor [monitorCount];
      GdkRectangle dest = new GdkRectangle ();
      for (int i = 0; i < monitorCount; i++) {
        OS.gdk_screen_get_monitor_geometry (screen, i, dest);
        Monitor monitor = new Monitor ();
        monitor.handle = i;
        monitor.x = dest.x;
        monitor.y = dest.y;
        monitor.width = dest.width;
        monitor.height = dest.height;
        monitor.clientX = monitor.x;
        monitor.clientY = monitor.y;
        monitor.clientWidth = monitor.width;
        monitor.clientHeight = monitor.height;
        monitors [i] = monitor;
      }
    }
  }
  if (monitors == null) {
    /* No multimonitor support detected, default to one monitor */
    Monitor monitor = new Monitor ();
    Rectangle bounds = getBounds ();
    monitor.x = bounds.x;
    monitor.y = bounds.y;
    monitor.width = bounds.width;
    monitor.height = bounds.height;
    monitor.clientX = monitor.x;
    monitor.clientY = monitor.y;
    monitor.clientWidth = monitor.width;
    monitor.clientHeight = monitor.height;
    monitors = new Monitor [] { monitor };      
  }
  return monitors;
}

/**
 * Returns the primary monitor for that device.
 * 
 * @return the primary monitor
 * 
 * @since 3.0
 */
public Monitor getPrimaryMonitor () {
  checkDevice ();
  Monitor [] monitors = getMonitors ();
  return monitors [0];
}

/**
 * Returns an array containing all shells which have not been
 * disposed and have the receiver as their display.
 *
 * @return the receiver's shells
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Shell [] getShells () {
  checkDevice ();
  int length = 0;
  for (int i=0; i<widgetTable.length; i++) {
    Widget widget = widgetTable [i];
    if (widget != null && widget instanceof Shell) length++;
  }
  int index = 0;
  Shell [] result = new Shell [length];
  for (int i=0; i<widgetTable.length; i++) {
    Widget widget = widgetTable [i];
    if (widget != null && widget instanceof Shell) {
      int j = 0;
      while (j < index) {
        if (result [j] == widget) break;
        j++;
      }
      if (j == index) result [index++] = (Shell) widget;
    }
  }
  if (index == length) return result;
  Shell [] newResult = new Shell [index];
  System.arraycopy (result, 0, newResult, 0, index);
  return newResult;
}

/**
 * Returns the thread that has invoked <code>syncExec</code>
 * or null if no such runnable is currently being invoked by
 * the user-interface thread.
 * <p>
 * Note: If a runnable invoked by asyncExec is currently
 * running, this method will return null.
 * </p>
 *
 * @return the receiver's sync-interface thread
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Thread getSyncThread () {
  if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
  return synchronizer.syncThread;
}

/**
 * Returns the matching standard color for the given
 * constant, which should be one of the color constants
 * specified in class <code>SWT</code>. Any value other
 * than one of the SWT color constants which is passed
 * in will result in the color black. This color should
 * not be free'd because it was allocated by the system,
 * not the application.
 *
 * @param id the color constant
 * @return the matching color
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see SWT
 */
public Color getSystemColor (int id) {
  checkDevice ();
  GdkColor gdkColor = null;
  switch (id) {
    case SWT.COLOR_INFO_FOREGROUND:           gdkColor = COLOR_INFO_FOREGROUND; break;
    case SWT.COLOR_INFO_BACKGROUND:           gdkColor = COLOR_INFO_BACKGROUND; break;
    case SWT.COLOR_TITLE_FOREGROUND:          gdkColor = COLOR_TITLE_FOREGROUND; break;
    case SWT.COLOR_TITLE_BACKGROUND:          gdkColor = COLOR_TITLE_BACKGROUND; break;
    case SWT.COLOR_TITLE_BACKGROUND_GRADIENT:      gdkColor = COLOR_TITLE_BACKGROUND_GRADIENT; break;
    case SWT.COLOR_TITLE_INACTIVE_FOREGROUND:      gdkColor = COLOR_TITLE_INACTIVE_FOREGROUND; break;
    case SWT.COLOR_TITLE_INACTIVE_BACKGROUND:      gdkColor = COLOR_TITLE_INACTIVE_BACKGROUND; break;
    case SWT.COLOR_TITLE_INACTIVE_BACKGROUND_GRADIENT:  gdkColor = COLOR_TITLE_INACTIVE_BACKGROUND_GRADIENT; break;
    case SWT.COLOR_WIDGET_DARK_SHADOW:          gdkColor = COLOR_WIDGET_DARK_SHADOW; break;
    case SWT.COLOR_WIDGET_NORMAL_SHADOW:        gdkColor = COLOR_WIDGET_NORMAL_SHADOW; break;
    case SWT.COLOR_WIDGET_LIGHT_SHADOW:         gdkColor = COLOR_WIDGET_LIGHT_SHADOW; break;
    case SWT.COLOR_WIDGET_HIGHLIGHT_SHADOW:        gdkColor = COLOR_WIDGET_HIGHLIGHT_SHADOW; break;
    case SWT.COLOR_WIDGET_BACKGROUND:           gdkColor = COLOR_WIDGET_BACKGROUND; break;
    case SWT.COLOR_WIDGET_FOREGROUND:           gdkColor = COLOR_WIDGET_FOREGROUND; break;
    case SWT.COLOR_WIDGET_BORDER:             gdkColor = COLOR_WIDGET_BORDER; break;
    case SWT.COLOR_LIST_FOREGROUND:           gdkColor = COLOR_LIST_FOREGROUND; break;
    case SWT.COLOR_LIST_BACKGROUND:           gdkColor = COLOR_LIST_BACKGROUND; break;
    case SWT.COLOR_LIST_SELECTION:             gdkColor = COLOR_LIST_SELECTION; break;
    case SWT.COLOR_LIST_SELECTION_TEXT:         gdkColor = COLOR_LIST_SELECTION_TEXT; break;
    default:
      return super.getSystemColor (id);  
  }
  if (gdkColor == null) return super.getSystemColor (SWT.COLOR_BLACK);
  return Color.gtk_new (this, gdkColor);
}

/**
 * Returns the matching standard platform cursor for the given
 * constant, which should be one of the cursor constants
 * specified in class <code>SWT</code>. This cursor should
 * not be free'd because it was allocated by the system,
 * not the application.  A value of <code>null</code> will
 * be returned if the supplied constant is not an swt cursor
 * constant. 
 *
 * @param id the swt cursor constant
 * @return the corresponding cursor or <code>null</code>
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see SWT#CURSOR_ARROW
 * @see SWT#CURSOR_WAIT
 * @see SWT#CURSOR_CROSS
 * @see SWT#CURSOR_APPSTARTING
 * @see SWT#CURSOR_HELP
 * @see SWT#CURSOR_SIZEALL
 * @see SWT#CURSOR_SIZENESW
 * @see SWT#CURSOR_SIZENS
 * @see SWT#CURSOR_SIZENWSE
 * @see SWT#CURSOR_SIZEWE
 * @see SWT#CURSOR_SIZEN
 * @see SWT#CURSOR_SIZES
 * @see SWT#CURSOR_SIZEE
 * @see SWT#CURSOR_SIZEW
 * @see SWT#CURSOR_SIZENE
 * @see SWT#CURSOR_SIZESE
 * @see SWT#CURSOR_SIZESW
 * @see SWT#CURSOR_SIZENW
 * @see SWT#CURSOR_UPARROW
 * @see SWT#CURSOR_IBEAM
 * @see SWT#CURSOR_NO
 * @see SWT#CURSOR_HAND
 * 
 * @since 3.0
 */
public Cursor getSystemCursor (int id) {
  checkDevice ();
  if (!(0 <= id && id < cursors.length)) return null;
  if (cursors [id] == null) {
    cursors [id] = new Cursor (this, id);
  }
  return cursors [id];
}

/**
 * Returns the matching standard platform image for the given
 * constant, which should be one of the icon constants
 * specified in class <code>SWT</code>. This image should
 * not be free'd because it was allocated by the system,
 * not the application.  A value of <code>null</code> will
 * be returned either if the supplied constant is not an
 * swt icon constant or if the platform does not define an
 * image that corresponds to the constant. 
 *
 * @param id the swt icon constant
 * @return the corresponding image or <code>null</code>
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see SWT#ICON_ERROR
 * @see SWT#ICON_INFORMATION
 * @see SWT#ICON_QUESTION
 * @see SWT#ICON_WARNING
 * @see SWT#ICON_WORKING
 * 
 * @since 3.0
 */
public Image getSystemImage (int id) {
  long /*int*/ imagePixmap = 0, imageMask = 0;
  switch (id) {
    case SWT.ICON_ERROR:
      if (errorPixmap == 0) {
        long /*int*/[] image = createImage ("gtk-dialog-error");
        if (image != null) {
          errorPixmap = image [0];
          errorMask = image [1];
        }
      }
      imagePixmap = errorPixmap;
      imageMask = errorMask;
      break;
    case SWT.ICON_INFORMATION:
    case SWT.ICON_WORKING:
      if (infoPixmap == 0) {
        long /*int*/[] image = createImage ("gtk-dialog-info");
        if (image != null) {
          infoPixmap = image [0];
          infoMask = image [1];
        }
      }
      imagePixmap = infoPixmap;
      imageMask = infoMask;
      break;
    case SWT.ICON_QUESTION:
      if (questionPixmap == 0) {
        long /*int*/[] image = createImage ("gtk-dialog-question");
        if (image != null) {
          questionPixmap = image [0];
          questionMask = image [1];
        }
      }
      imagePixmap = questionPixmap;
      imageMask = questionMask;
      break;
    case SWT.ICON_WARNING:
      if (warningPixmap == 0) {
        long /*int*/[] image = createImage ("gtk-dialog-warning");
        if (image != null) {
          warningPixmap = image [0];
          warningMask = image [1];
        }
      }
      imagePixmap = warningPixmap;
      imageMask = warningMask;
      break;
  }
  if (imagePixmap == 0) return null;
  return Image.gtk_new (this, SWT.ICON, imagePixmap, imageMask);
}

void initializeSystemResources () {
  long /*int*/ shellHandle = OS.gtk_window_new (OS.GTK_WINDOW_TOPLEVEL);
  if (shellHandle == 0) SWT.error (SWT.ERROR_NO_HANDLES);
  OS.gtk_widget_realize (shellHandle);
  
  long /*int*/ tooltipShellHandle = OS.gtk_window_new (OS.GTK_WINDOW_POPUP);
  if (tooltipShellHandle == 0) SWT.error (SWT.ERROR_NO_HANDLES);
  byte[] gtk_tooltips = Converter.wcsToMbcs (null, "gtk-tooltips", true);
  OS.gtk_widget_set_name (tooltipShellHandle, gtk_tooltips);
  OS.gtk_widget_realize (tooltipShellHandle);

  GdkColor gdkColor;
  long /*int*/ style = OS.gtk_widget_get_style (shellHandle);  
  long /*int*/ tooltipStyle = OS.gtk_widget_get_style (tooltipShellHandle);
  
  defaultFont = OS.pango_font_description_copy (OS.gtk_style_get_font_desc (style));

  gdkColor = new GdkColor();
  OS.gtk_style_get_black (style, gdkColor);
  COLOR_WIDGET_DARK_SHADOW = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_dark (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_WIDGET_NORMAL_SHADOW = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_bg (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_WIDGET_LIGHT_SHADOW = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_light (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_WIDGET_HIGHLIGHT_SHADOW = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_fg (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_WIDGET_FOREGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_bg (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_WIDGET_BACKGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_text (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_TEXT_FOREGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_base (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_TEXT_BACKGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_text (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_LIST_FOREGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_base (style, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_LIST_BACKGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_text (style, OS.GTK_STATE_SELECTED, gdkColor);
  COLOR_LIST_SELECTION_TEXT = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_base (style, OS.GTK_STATE_SELECTED, gdkColor);
  COLOR_LIST_SELECTION = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_fg (tooltipStyle, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_INFO_FOREGROUND = gdkColor;

  gdkColor = new GdkColor();
  OS.gtk_style_get_bg (tooltipStyle, OS.GTK_STATE_NORMAL, gdkColor);
  COLOR_INFO_BACKGROUND = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_bg (style, OS.GTK_STATE_SELECTED, gdkColor);
  COLOR_TITLE_BACKGROUND = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_fg (style, OS.GTK_STATE_SELECTED, gdkColor);
  COLOR_TITLE_FOREGROUND = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_light (style, OS.GTK_STATE_SELECTED, gdkColor);
  COLOR_TITLE_BACKGROUND_GRADIENT = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_bg (style, OS.GTK_STATE_INSENSITIVE, gdkColor);
  COLOR_TITLE_INACTIVE_BACKGROUND = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_fg (style, OS.GTK_STATE_INSENSITIVE, gdkColor);
  COLOR_TITLE_INACTIVE_FOREGROUND = gdkColor;
  
  gdkColor = new GdkColor();
  OS.gtk_style_get_light (style, OS.GTK_STATE_INSENSITIVE, gdkColor);
  COLOR_TITLE_INACTIVE_BACKGROUND_GRADIENT = gdkColor;

  OS.gtk_widget_destroy (tooltipShellHandle);
  OS.gtk_widget_destroy (shellHandle);
}

/**
 * Returns a reasonable font for applications to use.
 * On some platforms, this will match the "default font"
 * or "system font" if such can be found.  This font
 * should not be free'd because it was allocated by the
 * system, not the application.
 * <p>
 * Typically, applications which want the default look
 * should simply not set the font on the widgets they
 * create. Widgets are always created with the correct
 * default font for the class of user-interface component
 * they represent.
 * </p>
 *
 * @return a font
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Font getSystemFont () {
  checkDevice ();
  return Font.gtk_new (this, defaultFont);
}

/**
 * Returns the single instance of the system tray.
 *
 * @return the receiver's user-interface thread
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 */
public Tray getSystemTray () {
  if (tray != null) return tray;
  return tray = new Tray (this, SWT.NULL);
}

/**
 * Returns the user-interface thread for the receiver.
 *
 * @return the receiver's user-interface thread
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public Thread getThread () {
  if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
  return thread;
}

Widget getWidget (long /*int*/ handle) {
  if (handle == 0) return null;
  long /*int*/ index = OS.g_object_get_qdata (handle, SWT_OBJECT_INDEX) - 1;
  if (0 <= index && index < widgetTable.length) return widgetTable [(int)/*64*/index];
  return null;  
}

/**
 * Initializes any internal resources needed by the
 * device.
 * <p>
 * This method is called after <code>create</code>.
 * </p>
 * 
 * @see #create
 */
protected void init () {
  super.init ();
  initializeCallbacks ();
  initializeSystemResources ();
  initializeWidgetTable ();
}

void initializeCallbacks () {
  windowCallback2 = new Callback (this, "windowProc", 2);
  windowProc2 = windowCallback2.getAddress ();
  if (windowProc2 == 0) SWT.error (SWT.ERROR_NO_MORE_CALLBACKS);
    
  windowCallback3 = new Callback (this, "windowProc", 3);
  windowProc3 = windowCallback3.getAddress ();
  if (windowProc3 == 0) SWT.error (SWT.ERROR_NO_MORE_CALLBACKS);  
  
  windowCallback4 = new Callback (this, "windowProc", 4);
  windowProc4 = windowCallback4.getAddress ();
  if (windowProc4 == 0) SWT.error (SWT.ERROR_NO_MORE_CALLBACKS);  
  
  windowCallback5 = new Callback (this, "windowProc", 5);
  windowProc5 = windowCallback5.getAddress ();
  if (windowProc5 == 0) SWT.error (SWT.ERROR_NO_MORE_CALLBACKS);
  
  timerCallback = new Callback (this, "timerProc", 1);
  timerProc = timerCallback.getAddress ();
  if (timerProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);

  windowTimerCallback = new Callback (this, "windowTimerProc", 1);
  windowTimerProc = windowTimerCallback.getAddress ();
  if (windowTimerProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);
  
  mouseHoverCallback = new Callback (this, "mouseHoverProc", 1);
  mouseHoverProc = mouseHoverCallback.getAddress ();
  if (mouseHoverProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);

  caretCallback = new Callback(this, "caretProc", 1);
  caretProc = caretCallback.getAddress();
  if (caretProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);

  menuPositionCallback = new Callback(this, "menuPositionProc", 5);
  menuPositionProc = menuPositionCallback.getAddress();
  if (menuPositionProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);

  shellMapCallback = new Callback(this, "shellMapProc", 3);
  shellMapProc = shellMapCallback.getAddress();
  if (shellMapProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);
  
  treeSelectionCallback = new Callback(this, "treeSelectionProc", 4);
  treeSelectionProc = treeSelectionCallback.getAddress();
  if (treeSelectionProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);
  
  textCellDataCallback = new Callback (this, "textCellDataProc", 5);
  textCellDataProc = textCellDataCallback.getAddress ();
  if (textCellDataProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);
  
  pixbufCellDataCallback = new Callback (this, "pixbufCellDataProc", 5);
  pixbufCellDataProc = pixbufCellDataCallback.getAddress ();
  if (pixbufCellDataProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);

  checkIfEventCallback = new Callback (this, "checkIfEventProc", 3);
  checkIfEventProc = checkIfEventCallback.getAddress ();
  if (checkIfEventProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);

  filterCallback = new Callback (this, "filterProc", 3);
  filterProc = filterCallback.getAddress ();
  if (filterProc == 0) error (SWT.ERROR_NO_MORE_CALLBACKS);
}

void initializeWidgetTable () {
  indexTable = new int [GROW_SIZE];
  widgetTable = new Widget [GROW_SIZE];
  for (int i=0; i<GROW_SIZE-1; i++) indexTable [i] = i + 1;
  indexTable [GROW_SIZE - 1] = -1;
}

/**   
 * Invokes platform specific functionality to dispose a GC handle.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Display</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param hDC the platform specific GC handle
 * @param data the platform specific GC data 
 */
public void internal_dispose_GC (long /*int*/ gdkGC, GCData data) {
  OS.g_object_unref (gdkGC);
}

/**   
 * Invokes platform specific functionality to allocate a new GC handle.
 * <p>
 * <b>IMPORTANT:</b> This method is <em>not</em> part of the public
 * API for <code>Display</code>. It is marked public only so that it
 * can be shared within the packages provided by SWT. It is not
 * available on all platforms, and should never be called from
 * application code.
 * </p>
 *
 * @param data the platform specific GC data 
 * @return the platform specific GC handle
 * 
 * @exception SWTError <ul>
 *    <li>ERROR_NO_HANDLES if a handle could not be obtained for image creation</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public long /*int*/ internal_new_GC (GCData data) {
  if (isDisposed()) SWT.error(SWT.ERROR_DEVICE_DISPOSED);
  long /*int*/ root = OS.GDK_ROOT_PARENT ();
  long /*int*/ gdkGC = OS.gdk_gc_new (root);
  if (gdkGC == 0) SWT.error (SWT.ERROR_NO_HANDLES);
  if (data != null) {
    int mask = SWT.LEFT_TO_RIGHT | SWT.RIGHT_TO_LEFT;
    if ((data.style & mask) == 0) {
      data.style |= SWT.LEFT_TO_RIGHT;
    }
    data.device = this;
    data.drawable = root;
    data.font = defaultFont;
  }
  return gdkGC;
}

boolean isValidThread () {
  return thread == Thread.currentThread ();
}

/**
 * Maps a point from one coordinate system to another.
 * When the control is null, coordinates are mapped to
 * the display.
 * <p>
 * NOTE: On right-to-left platforms where the coordinate
 * systems are mirrored, special care needs to be taken
 * when mapping coordinates from one control to another
 * to ensure the result is correctly mirrored.
 * 
 * Mapping a point that is the origin of a rectangle and
 * then adding the width and height is not equivalent to
 * mapping the rectangle.  When one control is mirrored
 * and the other is not, adding the width and height to a
 * point that was mapped causes the rectangle to extend
 * in the wrong direction.  Mapping the entire rectangle
 * instead of just one point causes both the origin and
 * the corner of the rectangle to be mapped.
 * </p>
 * 
 * @param from the source <code>Control</code> or <code>null</code>
 * @param to the destination <code>Control</code> or <code>null</code>
 * @param point to be mapped 
 * @return point with mapped coordinates 
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the rectangle is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.1.2
 */
public Point map (Control from, Control to, Point point) {
  checkDevice ();
  if (point == null) error (SWT.ERROR_NULL_ARGUMENT);  
  return map (from, to, point.x, point.y);
}

/**
 * Maps a point from one coordinate system to another.
 * When the control is null, coordinates are mapped to
 * the display.
 * <p>
 * NOTE: On right-to-left platforms where the coordinate
 * systems are mirrored, special care needs to be taken
 * when mapping coordinates from one control to another
 * to ensure the result is correctly mirrored.
 * 
 * Mapping a point that is the origin of a rectangle and
 * then adding the width and height is not equivalent to
 * mapping the rectangle.  When one control is mirrored
 * and the other is not, adding the width and height to a
 * point that was mapped causes the rectangle to extend
 * in the wrong direction.  Mapping the entire rectangle
 * instead of just one point causes both the origin and
 * the corner of the rectangle to be mapped.
 * </p>
 * 
 * @param from the source <code>Control</code> or <code>null</code>
 * @param to the destination <code>Control</code> or <code>null</code>
 * @param x coordinates to be mapped
 * @param y coordinates to be mapped
 * @return point with mapped coordinates
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.1.2
 */
public Point map (Control from, Control to, int x, int y) {
  checkDevice ();
  if (from != null && from.isDisposed()) error (SWT.ERROR_INVALID_ARGUMENT);
  if (to != null && to.isDisposed()) error (SWT.ERROR_INVALID_ARGUMENT);
  Point point = new Point (x, y);
  if (from != null) {
    long /*int*/ eventHandle = from.eventHandle ();
    OS.gtk_widget_realize (eventHandle);
    long /*int*/ window = OS.GTK_WIDGET_WINDOW (eventHandle);
    int [] origin_x = new int [1], origin_y = new int [1];
    OS.gdk_window_get_origin (window, origin_x, origin_y);
    point.x += origin_x [0];
    point.y += origin_y [0];
  }
  if (to != null) {
    long /*int*/ eventHandle = to.eventHandle ();
    OS.gtk_widget_realize (eventHandle);
    long /*int*/ window = OS.GTK_WIDGET_WINDOW (eventHandle);
    int [] origin_x = new int [1], origin_y = new int [1];
    OS.gdk_window_get_origin (window, origin_x, origin_y);
    point.x -= origin_x [0];
    point.y -= origin_y [0];
  }
  return point;
}

/**
 * Maps a point from one coordinate system to another.
 * When the control is null, coordinates are mapped to
 * the display.
 * <p>
 * NOTE: On right-to-left platforms where the coordinate
 * systems are mirrored, special care needs to be taken
 * when mapping coordinates from one control to another
 * to ensure the result is correctly mirrored.
 * 
 * Mapping a point that is the origin of a rectangle and
 * then adding the width and height is not equivalent to
 * mapping the rectangle.  When one control is mirrored
 * and the other is not, adding the width and height to a
 * point that was mapped causes the rectangle to extend
 * in the wrong direction.  Mapping the entire rectangle
 * instead of just one point causes both the origin and
 * the corner of the rectangle to be mapped.
 * </p>
 * 
 * @param from the source <code>Control</code> or <code>null</code>
 * @param to the destination <code>Control</code> or <code>null</code>
 * @param rectangle to be mapped
 * @return rectangle with mapped coordinates
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the rectangle is null</li>
 *    <li>ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.1.2
 */
public Rectangle map (Control from, Control to, Rectangle rectangle) {
  checkDevice();
  if (rectangle == null) error (SWT.ERROR_NULL_ARGUMENT);
  return map (from, to, rectangle.x, rectangle.y, rectangle.width, rectangle.height);
}

static char mbcsToWcs (char ch) {
  int key = ch & 0xFFFF;
  if (key <= 0x7F) return ch;
  byte [] buffer;
  if (key <= 0xFF) {
    buffer = new byte [1];
    buffer [0] = (byte) key;
  } else {
    buffer = new byte [2];
    buffer [0] = (byte) ((key >> 8) & 0xFF);
    buffer [1] = (byte) (key & 0xFF);
  }
  char [] result = Converter.mbcsToWcs (null, buffer);
  if (result.length == 0) return 0;
  return result [0];
}

long /*int*/ menuPositionProc (long /*int*/ menu, long /*int*/ x, long /*int*/ y, long /*int*/ push_in, long /*int*/ user_data) {
  Widget widget = getWidget (menu);
  if (widget == null) return 0;
  return widget.menuPositionProc (menu, x, y, push_in, user_data);  
}

/**
 * Maps a point from one coordinate system to another.
 * When the control is null, coordinates are mapped to
 * the display.
 * <p>
 * NOTE: On right-to-left platforms where the coordinate
 * systems are mirrored, special care needs to be taken
 * when mapping coordinates from one control to another
 * to ensure the result is correctly mirrored.
 * 
 * Mapping a point that is the origin of a rectangle and
 * then adding the width and height is not equivalent to
 * mapping the rectangle.  When one control is mirrored
 * and the other is not, adding the width and height to a
 * point that was mapped causes the rectangle to extend
 * in the wrong direction.  Mapping the entire rectangle
 * instead of just one point causes both the origin and
 * the corner of the rectangle to be mapped.
 * </p>
 * 
 * @param from the source <code>Control</code> or <code>null</code>
 * @param to the destination <code>Control</code> or <code>null</code>
 * @param x coordinates to be mapped
 * @param y coordinates to be mapped
 * @param width coordinates to be mapped
 * @param height coordinates to be mapped
 * @return rectangle with mapped coordinates
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_INVALID_ARGUMENT - if the Control from or the Control to have been disposed</li> 
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.1.2
 */
public Rectangle map (Control from, Control to, int x, int y, int width, int height) {
  checkDevice();
  if (from != null && from.isDisposed()) error (SWT.ERROR_INVALID_ARGUMENT);
  if (to != null && to.isDisposed()) error (SWT.ERROR_INVALID_ARGUMENT);
  Rectangle rect = new Rectangle (x, y, width, height);
  if (from != null) {
    long /*int*/ eventHandle = from.eventHandle ();
    OS.gtk_widget_realize (eventHandle);
    long /*int*/ window = OS.GTK_WIDGET_WINDOW (eventHandle);
    int [] origin_x = new int [1], origin_y = new int [1];
    OS.gdk_window_get_origin (window, origin_x, origin_y);
    rect.x += origin_x [0];
    rect.y += origin_y [0];
  }
  if (to != null) {
    long /*int*/ eventHandle = to.eventHandle ();
    OS.gtk_widget_realize (eventHandle);
    long /*int*/ window = OS.GTK_WIDGET_WINDOW (eventHandle);
    int [] origin_x = new int [1], origin_y = new int [1];
    OS.gdk_window_get_origin (window, origin_x, origin_y);
    rect.x -= origin_x [0];
    rect.y -= origin_y [0];
  }
  return rect;
}

long /*int*/ mouseHoverProc (long /*int*/ handle) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.hoverProc (handle);
}

/**
 * Generate a low level system event.
 * 
 * <code>post</code> is used to generate low level keyboard
 * and mouse events. The intent is to enable automated UI
 * testing by simulating the input from the user.  Most
 * SWT applications should never need to call this method.
 * 
 * <p>
 * <b>Event Types:</b>
 * <p>KeyDown, KeyUp
 * <p>The following fields in the <code>Event</code> apply:
 * <ul>
 * <li>(in) type KeyDown or KeyUp</li>
 * <p> Either one of:
 * <li>(in) character a character that corresponds to a keyboard key</li>
 * <li>(in) keyCode the key code of the key that was typed,
 *          as defined by the key code constants in class <code>SWT</code></li>
 * </ul>
 * <p>MouseDown, MouseUp</p>
 * <p>The following fields in the <code>Event</code> apply:
 * <ul>
 * <li>(in) type MouseDown or MouseUp
 * <li>(in) button the button that is pressed or released
 * </ul>
 * <p>MouseMove</p>
 * <p>The following fields in the <code>Event</code> apply:
 * <ul>
 * <li>(in) type MouseMove
 * <li>(in) x the x coordinate to move the mouse pointer to in screen coordinates
 * <li>(in) y the y coordinate to move the mouse pointer to in screen coordinates
 * </ul>
 * </dl>
 * 
 * @param event the event to be generated
 * 
 * @return true if the event was generated or false otherwise
 * 
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the event is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @since 3.0
 * 
 */
public boolean post (Event event) {
  if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
  if (event == null) error (SWT.ERROR_NULL_ARGUMENT);
  if (!OS.GDK_WINDOWING_X11()) return false;
  long /*int*/ xDisplay = OS.GDK_DISPLAY ();
  int type = event.type;
  switch (type) {
    case SWT.KeyDown:
    case SWT.KeyUp: {
      int keyCode = 0;
      long /*int*/ keysym = untranslateKey (event.keyCode);
      if (keysym != 0) keyCode = OS.XKeysymToKeycode (xDisplay, keysym);
      if (keyCode == 0) {
        char key = event.character;
        switch (key) {
          case '\r': keysym = OS.GDK_Return; break;
          default: keysym = wcsToMbcs (key);
        }
        keyCode = OS.XKeysymToKeycode (xDisplay, keysym);
        if (keyCode == 0) return false;
      }
      OS.XTestFakeKeyEvent (xDisplay, keyCode, type == SWT.KeyDown, 0);
      return true;
    }
    case SWT.MouseDown:
    case SWT.MouseMove: 
    case SWT.MouseUp: {
      if (type == SWT.MouseMove) {
        OS.XTestFakeMotionEvent (xDisplay, -1, event.x, event.y, 0);
      } else {
        int button = event.button;
        if (button < 1 || button > 3) return false;
        OS.XTestFakeButtonEvent (xDisplay, button, type == SWT.MouseDown, 0);
      }
      return true;
    }
  }
  return false;
}

void postEvent (Event event) {
  /*
  * Place the event at the end of the event queue.
  * This code is always called in the Display's
  * thread so it must be re-enterant but does not
  * need to be synchronized.
  */
  if (eventQueue == null) eventQueue = new Event [4];
  int index = 0;
  int length = eventQueue.length;
  while (index < length) {
    if (eventQueue [index] == null) break;
    index++;
  }
  if (index == length) {
    Event [] newQueue = new Event [length + 4];
    System.arraycopy (eventQueue, 0, newQueue, 0, length);
    eventQueue = newQueue;
  }
  eventQueue [index] = event;
}

void putGdkEvents () {
  if (gdkEventCount != 0) {
    for (int i = 0; i < gdkEventCount; i++) {
      if (gdkEventWidgets [i] == null || !gdkEventWidgets [i].isDisposed ()) {
        OS.gdk_event_put (gdkEvents [i]);
        OS.gdk_event_free (gdkEvents [i]);
      }
    }
    gdkEvents = null;
    gdkEventWidgets = null;
    gdkEventCount = 0;
  }
}

/**
 * Reads an event from the operating system's event queue,
 * dispatches it appropriately, and returns <code>true</code>
 * if there is potentially more work to do, or <code>false</code>
 * if the caller can sleep until another event is placed on
 * the event queue.
 * <p>
 * In addition to checking the system event queue, this method also
 * checks if any inter-thread messages (created by <code>syncExec()</code>
 * or <code>asyncExec()</code>) are waiting to be processed, and if
 * so handles them before returning.
 * </p>
 *
 * @return <code>false</code> if the caller can sleep upon return from this method
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #sleep
 * @see #wake
 */
public boolean readAndDispatch () {
  checkDevice ();
  runPopups ();
  int status = OS.gtk_events_pending ();
  if (status != 0) {
    OS.gtk_main_iteration ();
    runDeferredEvents ();
    return true;
  }
  return runAsyncMessages ();
}

synchronized void register () {
  for (int i=0; i<Displays.length; i++) {
    if (Displays [i] == null) {
      Displays [i] = this;
      return;
    }
  }
  Display [] newDisplays = new Display [Displays.length + 4];
  System.arraycopy (Displays, 0, newDisplays, 0, Displays.length);
  newDisplays [Displays.length] = this;
  Displays = newDisplays;
}

/**
 * Releases any internal resources back to the operating
 * system and clears all fields except the device handle.
 * <p>
 * Disposes all shells which are currently open on the display. 
 * After this method has been invoked, all related related shells
 * will answer <code>true</code> when sent the message
 * <code>isDisposed()</code>.
 * </p><p>
 * When a device is destroyed, resources that were acquired
 * on behalf of the programmer need to be returned to the
 * operating system.  For example, if the device allocated a
 * font to be used as the system font, this font would be
 * freed in <code>release</code>.  Also,to assist the garbage
 * collector and minimize the amount of memory that is not
 * reclaimed when the programmer keeps a reference to a
 * disposed device, all fields except the handle are zero'd.
 * The handle is needed by <code>destroy</code>.
 * </p>
 * This method is called before <code>destroy</code>.
 * 
 * @see #dispose
 * @see #destroy
 */
protected void release () {
  sendEvent (SWT.Dispose, new Event ());
  Shell [] shells = getShells ();
  for (int i=0; i<shells.length; i++) {
    Shell shell = shells [i];
    if (!shell.isDisposed ())  shell.dispose ();
  }
  if (tray != null) tray.dispose ();
  tray = null;
  while (readAndDispatch ()) {}
  if (disposeList != null) {
    for (int i=0; i<disposeList.length; i++) {
      if (disposeList [i] != null) disposeList [i].run ();
    }
  }
  disposeList = null;
  synchronizer.releaseSynchronizer ();
  synchronizer = null;
  releaseDisplay ();
  super.release ();
}

void releaseDisplay () {
  windowCallback2.dispose ();  windowCallback2 = null;
  windowCallback3.dispose ();  windowCallback3 = null;
  windowCallback4.dispose ();  windowCallback4 = null;
  windowCallback5.dispose ();  windowCallback5 = null;
  
  /* Dispose xfilter callback */
  filterCallback.dispose(); filterCallback = null;
  filterProc = 0;

  /* Dispose checkIfEvent callback */
  checkIfEventCallback.dispose(); checkIfEventCallback = null;
  checkIfEventProc = 0;
  
  /* Dispose preedit window */
  if (preeditWindow != 0) OS.gtk_widget_destroy (preeditWindow);
  imControl = null;

  /* Dispose the menu callback */
  menuPositionCallback.dispose (); menuPositionCallback = null;
  menuPositionProc = 0;

  /* Dispose the shell map callback */
  shellMapCallback.dispose (); shellMapCallback = null;
  shellMapProc = 0;
  
  /* Dispose GtkTreeView callbacks */
  treeSelectionCallback.dispose (); treeSelectionCallback = null;
  treeSelectionProc = 0;
  textCellDataCallback.dispose (); textCellDataCallback = null;
  textCellDataProc = 0;
  pixbufCellDataCallback.dispose (); pixbufCellDataCallback = null;
  pixbufCellDataProc = 0;

  /* Dispose the caret callback */
  if (caretId != 0) OS.gtk_timeout_remove (caretId);
  caretId = 0;
  caretProc = 0;
  caretCallback.dispose ();
  caretCallback = null;
  
  /* Dispose the timer callback */
  if (timerIds != null) {
    for (int i=0; i<timerIds.length; i++) {
      if (timerIds [i] != 0) OS.gtk_timeout_remove (timerIds [i]);
    }
  }
  timerIds = null;
  timerList = null;
  timerProc = 0;
  timerCallback.dispose ();
  timerCallback = null;
  windowTimerProc = 0;
  windowTimerCallback.dispose ();
  windowTimerCallback = null;
  
  /* Dispose mouse hover callback */
  if (mouseHoverId != 0) OS.gtk_timeout_remove (mouseHoverId);
  mouseHoverId = 0;
  mouseHoverHandle = mouseHoverProc = 0;
  mouseHoverCallback.dispose ();
  mouseHoverCallback = null;

  thread = null;
  windowProc2 = windowProc3 = windowProc4 = windowProc5 = 0;
  
  /* Dispose the default font */
  if (defaultFont != 0) OS.pango_font_description_free (defaultFont);
  defaultFont = 0;
  
  /* Dispose the System Images */
  if (errorPixmap != 0) {
    OS.g_object_unref (errorPixmap);
    OS.g_object_unref (errorMask);
  }
  if (infoPixmap != 0) {
    OS.g_object_unref (infoPixmap);
    OS.g_object_unref (infoMask);
  }
  if (questionPixmap != 0) {
    OS.g_object_unref (questionPixmap);
    OS.g_object_unref (questionMask);
  }
  if (warningPixmap != 0) {
    OS.g_object_unref (warningPixmap);
    OS.g_object_unref (warningMask);
  }
  errorPixmap = infoPixmap = questionPixmap = warningPixmap = 0;
  errorMask = infoMask = questionMask = warningMask = 0;
  
  /* Release the System Cursors */
  for (int i = 0; i < cursors.length; i++) {
    if (cursors [i] != null) cursors [i].dispose ();
  }
  cursors = null;

  COLOR_WIDGET_DARK_SHADOW = COLOR_WIDGET_NORMAL_SHADOW = COLOR_WIDGET_LIGHT_SHADOW =
  COLOR_WIDGET_HIGHLIGHT_SHADOW = COLOR_WIDGET_BACKGROUND = COLOR_WIDGET_BORDER =
  COLOR_LIST_FOREGROUND = COLOR_LIST_BACKGROUND = COLOR_LIST_SELECTION = COLOR_LIST_SELECTION_TEXT =
  COLOR_INFO_BACKGROUND = null;
  
  /* Dispose the event callback */
  OS.gdk_event_handler_set (0, 0, 0);
  eventCallback.dispose ();  eventCallback = null;
}

/**
 * Removes the listener from the collection of listeners who will
 * be notifed when an event of the given type occurs anywhere in
 * this display.
 *
 * @param eventType the type of event to listen for
 * @param listener the listener which should no longer be notified when the event occurs
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 * </ul>
 *
 * @see Listener
 * @see #addFilter
 * @see #addListener
 * 
 * @since 3.0
 */
public void removeFilter (int eventType, Listener listener) {
  checkDevice ();
  if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
  if (filterTable == null) return;
  filterTable.unhook (eventType, listener);
  if (filterTable.size () == 0) filterTable = null;
}

long /*int*/ removeGdkEvent () {
  if (gdkEventCount == 0) return 0;
  long /*int*/ event = gdkEvents [0];
  --gdkEventCount;
  System.arraycopy (gdkEvents, 1, gdkEvents, 0, gdkEventCount);
  System.arraycopy (gdkEventWidgets, 1, gdkEventWidgets, 0, gdkEventCount);
  gdkEvents [gdkEventCount] = 0;
  gdkEventWidgets [gdkEventCount] = null;
  if (gdkEventCount == 0) {
    gdkEvents = null;
    gdkEventWidgets = null;
  }
  return event;
}

/**
 * Removes the listener from the collection of listeners who will
 * be notifed when an event of the given type occurs.
 *
 * @param eventType the type of event to listen for
 * @param listener the listener which should no longer be notified when the event occurs
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see Listener
 * @see #addListener
 * 
 * @since 2.0 
 */
public void removeListener (int eventType, Listener listener) {
  checkDevice ();
  if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
  if (eventTable == null) return;
  eventTable.unhook (eventType, listener);
}

void removeMouseHoverTimeout (long /*int*/ handle) {
  if (handle != mouseHoverHandle) return;
  if (mouseHoverId != 0) OS.gtk_timeout_remove (mouseHoverId);
  mouseHoverId = 0;
  mouseHoverHandle = 0;
}

void removePopup (Menu menu) {
  if (popups == null) return;
  for (int i=0; i<popups.length; i++) {
    if (popups [i] == menu) {
      popups [i] = null;
      return;
    }
  }
}

Widget removeWidget (long /*int*/ handle) {
  if (handle == 0) return null;
  Widget widget = null;
  int index = (int)/*64*/ OS.g_object_get_qdata (handle, SWT_OBJECT_INDEX) - 1;
  if (0 <= index && index < widgetTable.length) {
    widget = widgetTable [index];
    widgetTable [index] = null;
    indexTable [index] = freeSlot;
    freeSlot = index;
    OS.g_object_set_qdata (handle, SWT_OBJECT_INDEX, 0);
  }
  return widget;  
}

boolean runAsyncMessages () {
  return synchronizer.runAsyncMessages ();
}

boolean runDeferredEvents () {
  /*
  * Run deferred events.  This code is always
  * called in the Display's thread so it must
  * be re-enterant but need not be synchronized.
  */
  while (eventQueue != null) {
    
    /* Take an event off the queue */
    Event event = eventQueue [0];
    if (event == null) break;
    int length = eventQueue.length;
    System.arraycopy (eventQueue, 1, eventQueue, 0, --length);
    eventQueue [length] = null;

    /* Run the event */
    Widget widget = event.widget;
    if (widget != null && !widget.isDisposed ()) {
      Widget item = event.item;
      if (item == null || !item.isDisposed ()) {
        widget.sendEvent (event);
      }
    }

    /*
    * At this point, the event queue could
    * be null due to a recursive invokation
    * when running the event.
    */
  }

  /* Clear the queue */
  eventQueue = null;
  return true;
}

boolean runPopups () {
  if (popups == null) return false;
  boolean result = false;
  while (popups != null) {
    Menu menu = popups [0];
    if (menu == null) break;
    int length = popups.length;
    System.arraycopy (popups, 1, popups, 0, --length);
    popups [length] = null;
    runDeferredEvents ();
    menu._setVisible (true);
    result = true;
  }
  popups = null;
  return result;
}

/**
 * On platforms which support it, sets the application name
 * to be the argument. On Motif, for example, this can be used
 * to set the name used for resource lookup.
 *
 * @param name the new app name
 */
public static void setAppName (String name) {
  APP_NAME = name;
}

/**
 * Sets the location of the on-screen pointer relative to the top left corner
 * of the screen.  <b>Note: It is typically considered bad practice for a
 * program to move the on-screen pointer location.</b>
 *
 * @param x the new x coordinate for the cursor
 * @param y the new y coordinate for the cursor
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.1
 */
public void setCursorLocation (int x, int y) {
  checkDevice ();
  /* This is not supported on GTK */
}

/**
 * Sets the location of the on-screen pointer relative to the top left corner
 * of the screen.  <b>Note: It is typically considered bad practice for a
 * program to move the on-screen pointer location.</b>
 *
 * @param point new position
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_NULL_ARGUMENT - if the point is null
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @since 2.0
 */
public void setCursorLocation (Point point) {
  checkDevice ();
  if (point == null) error (SWT.ERROR_NULL_ARGUMENT);
  setCursorLocation (point.x, point.y);
}

/**
 * Sets the application defined property of the receiver
 * with the specified name to the given argument.
 * <p>
 * Applications may have associated arbitrary objects with the
 * receiver in this fashion. If the objects stored in the
 * properties need to be notified when the display is disposed
 * of, it is the application's responsibility provide a
 * <code>disposeExec()</code> handler which does so.
 * </p>
 *
 * @param key the name of the property
 * @param value the new value for the property
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the key is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #setData
 * @see #disposeExec
 */
public void setData (String key, Object value) {
  checkDevice ();
  if (key == null) error (SWT.ERROR_NULL_ARGUMENT);

  if (key.equals (DISPATCH_EVENT_KEY)) {
    if (value == null || value instanceof int []) {
      dispatchEvents = (int []) value;
      if (value == null) putGdkEvents ();
      return;
    }
  }

  /* Remove the key/value pair */
  if (value == null) {
    if (keys == null) return;
    int index = 0;
    while (index < keys.length && !keys [index].equals (key)) index++;
    if (index == keys.length) return;
    if (keys.length == 1) {
      keys = null;
      values = null;
    } else {
      String [] newKeys = new String [keys.length - 1];
      Object [] newValues = new Object [values.length - 1];
      System.arraycopy (keys, 0, newKeys, 0, index);
      System.arraycopy (keys, index + 1, newKeys, index, newKeys.length - index);
      System.arraycopy (values, 0, newValues, 0, index);
      System.arraycopy (values, index + 1, newValues, index, newValues.length - index);
      keys = newKeys;
      values = newValues;
    }
    return;
  }
  
  /* Add the key/value pair */
  if (keys == null) {
    keys = new String [] {key};
    values = new Object [] {value};
    return;
  }
  for (int i=0; i<keys.length; i++) {
    if (keys [i].equals (key)) {
      values [i] = value;
      return;
    }
  }
  String [] newKeys = new String [keys.length + 1];
  Object [] newValues = new Object [values.length + 1];
  System.arraycopy (keys, 0, newKeys, 0, keys.length);
  System.arraycopy (values, 0, newValues, 0, values.length);
  newKeys [keys.length] = key;
  newValues [values.length] = value;
  keys = newKeys;
  values = newValues;
}

/**
 * Sets the application defined, display specific data
 * associated with the receiver, to the argument.
 * The <em>display specific data</em> is a single,
 * unnamed field that is stored with every display. 
 * <p>
 * Applications may put arbitrary objects in this field. If
 * the object stored in the display specific data needs to
 * be notified when the display is disposed of, it is the
 * application's responsibility provide a
 * <code>disposeExec()</code> handler which does so.
 * </p>
 *
 * @param data the new display specific data
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #getData
 * @see #disposeExec
 */
public void setData (Object data) {
  checkDevice ();
  this.data = data;
}

/**
 * Sets the synchronizer used by the display to be
 * the argument, which can not be null.
 *
 * @param synchronizer the new synchronizer for the display (must not be null)
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the synchronizer is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 */
public void setSynchronizer (Synchronizer synchronizer) {
  checkDevice ();
  if (synchronizer == null) error (SWT.ERROR_NULL_ARGUMENT);
  if (this.synchronizer != null) {
    this.synchronizer.runAsyncMessages();
  }
  this.synchronizer = synchronizer;
}

void showIMWindow (Control control) {
  imControl = control;
  if (preeditWindow == 0) { 
    preeditWindow = OS.gtk_window_new (OS.GTK_WINDOW_POPUP);
    if (preeditWindow == 0) error (SWT.ERROR_NO_HANDLES);
    preeditLabel = OS.gtk_label_new (null);
    if (preeditLabel == 0) error (SWT.ERROR_NO_HANDLES);
    OS.gtk_container_add (preeditWindow, preeditLabel);
    OS.gtk_widget_show (preeditLabel);
  }
  long /*int*/ [] preeditString = new long /*int*/ [1];
  long /*int*/ [] pangoAttrs = new long /*int*/ [1];
  long /*int*/ imHandle = control.imHandle ();
  OS.gtk_im_context_get_preedit_string (imHandle, preeditString, pangoAttrs, null);
  if (preeditString [0] != 0 && OS.strlen (preeditString [0]) > 0) {
    OS.gtk_widget_modify_bg (preeditWindow,  OS.GTK_STATE_NORMAL, control.getBackgroundColor ());
    OS.gtk_widget_modify_fg (preeditLabel,  OS.GTK_STATE_NORMAL, control.getForegroundColor ());    
    OS.gtk_widget_modify_font (preeditLabel, control.getFontDescription ());
    if (pangoAttrs [0] != 0) OS.gtk_label_set_attributes (preeditLabel, pangoAttrs[0]);
    OS.gtk_label_set_text (preeditLabel, preeditString [0]);
    Point point = control.toDisplay (control.getIMCaretPos ());
    OS.gtk_window_move (preeditWindow, point.x, point.y);    
    GtkRequisition requisition = new GtkRequisition ();
    OS.gtk_widget_size_request (preeditLabel, requisition);
    OS.gtk_window_resize (preeditWindow, requisition.width, requisition.height);
    OS.gtk_widget_show (preeditWindow);
  } else {
    OS.gtk_widget_hide (preeditWindow);
  }    
  if (preeditString [0] != 0) OS.g_free (preeditString [0]);
  if (pangoAttrs [0] != 0) OS.pango_attr_list_unref (pangoAttrs [0]);  
}

/**
 * Causes the user-interface thread to <em>sleep</em> (that is,
 * to be put in a state where it does not consume CPU cycles)
 * until an event is received or it is otherwise awakened.
 *
 * @return <code>true</code> if an event requiring dispatching was placed on the queue.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #wake
 */
public boolean sleep () {
  checkDevice ();
  //TODO need to sleep waiting for the next event
  do {
    if (getMessageCount () != 0) break;
    if (OS.gtk_events_pending () != 0) break;
    try {
      synchronized (OS_LOCK) {
        OS_LOCK.wait (50);
      }
    } catch (Exception e) {
      return false;
    }
  } while (!wake);
  wake = false;
  return true;
}

/**
 * Causes the <code>run()</code> method of the runnable to
 * be invoked by the user-interface thread after the specified
 * number of milliseconds have elapsed. If milliseconds is less
 * than zero, the runnable is not executed.
 *
 * @param milliseconds the delay before running the runnable
 * @param runnable code to run on the user-interface thread
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the runnable is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #asyncExec
 */
public void timerExec (int milliseconds, Runnable runnable) {
  checkDevice ();
  if (runnable == null) error (SWT.ERROR_NULL_ARGUMENT);
  if (timerList == null) timerList = new Runnable [4];
  if (timerIds == null) timerIds = new int [4];  
  int index = 0;
  while (index < timerList.length) {
    if (timerList [index] == runnable) break;
    index++;
  }
  if (index != timerList.length) {
    OS.gtk_timeout_remove (timerIds [index]);
    timerList [index] = null;
    timerIds [index] = 0;
    if (milliseconds < 0) return;
  } else {
    if (milliseconds < 0) return;
    index = 0;
    while (index < timerList.length) {
      if (timerList [index] == null) break;
      index++;
    }
    if (index == timerList.length) {
      Runnable [] newTimerList = new Runnable [timerList.length + 4];
      System.arraycopy (timerList, 0, newTimerList, 0, timerList.length);
      timerList = newTimerList;
      int [] newTimerIds = new int [timerIds.length + 4];
      System.arraycopy (timerIds, 0, newTimerIds, 0, timerIds.length);
      timerIds = newTimerIds;
    }
  }
  int timerId = OS.gtk_timeout_add (milliseconds, timerProc, index);
  if (timerId != 0) {
    timerIds [index] = timerId;
    timerList [index] = runnable;
  }
}

long /*int*/ timerProc (long /*int*/ i) {
  if (timerList == null) return 0;
  int index = (int)/*64*/i;
  if (0 <= index && index < timerList.length) {
    Runnable runnable = timerList [index];
    timerList [index] = null;
    timerIds [index] = 0;
    if (runnable != null) runnable.run ();
  }
  return 0;
}

long /*int*/ caretProc (long /*int*/ clientData) {
  caretId = 0;
  if (currentCaret == null) {
    return 0;
  }
  if (currentCaret.blinkCaret()) {
    int blinkRate = currentCaret.blinkRate;
    caretId = OS.gtk_timeout_add (blinkRate, caretProc, 0);
  } else {
    currentCaret = null;
  }
  return 0;
}

long /*int*/ pixbufCellDataProc (long /*int*/ tree_column, long /*int*/ cell, long /*int*/ tree_model, long /*int*/ iter, long /*int*/ data) {
  Widget widget = getWidget (data);
  if (widget == null) return 0;
  return widget.pixbufCellDataProc (tree_column, cell, tree_model, iter, data);
}
long /*int*/ textCellDataProc (long /*int*/ tree_column, long /*int*/ cell, long /*int*/ tree_model, long /*int*/ iter, long /*int*/ data) {
  Widget widget = getWidget (data);
  if (widget == null) return 0;
  return widget.textCellDataProc (tree_column, cell, tree_model, iter, data);
}

long /*int*/ treeSelectionProc (long /*int*/ model, long /*int*/ path, long /*int*/ iter, long /*int*/ data) {
  Widget widget = getWidget (data);
  if (widget == null) return 0;
  return widget.treeSelectionProc (model, path, iter, treeSelection, treeSelectionLength++);
}

void sendEvent (int eventType, Event event) {
  if (eventTable == null && filterTable == null) {
    return;
  }
  if (event == null) event = new Event ();
  event.display = this;
  event.type = eventType;
  if (event.time == 0) event.time = getLastEventTime ();
  if (!filterEvent (event)) {
    if (eventTable != null) eventTable.sendEvent (event);
  }
}

void setCurrentCaret (Caret caret) {
  if (caretId != 0) OS.gtk_timeout_remove(caretId);
  caretId = 0;
  currentCaret = caret;
  if (caret == null) return;
  int blinkRate = currentCaret.blinkRate;
  caretId = OS.gtk_timeout_add (blinkRate, caretProc, 0); 
}

long /*int*/ shellMapProc (long /*int*/ handle, long /*int*/ arg0, long /*int*/ user_data) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.shellMapProc (handle, arg0, user_data);
}

/**
 * Causes the <code>run()</code> method of the runnable to
 * be invoked by the user-interface thread at the next 
 * reasonable opportunity. The thread which calls this method
 * is suspended until the runnable completes.
 *
 * @param runnable code to run on the user-interface thread.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_FAILED_EXEC - if an exception occured when executing the runnable</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 *
 * @see #asyncExec
 */
public void syncExec (Runnable runnable) {
  if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
  synchronizer.syncExec (runnable);
}

static int translateKey (int key) {
  for (int i=0; i<KeyTable.length; i++) {
    if (KeyTable [i] [0] == key) return KeyTable [i] [1];
  }
  return 0;
}

static int untranslateKey (int key) {
  for (int i=0; i<KeyTable.length; i++) {
    if (KeyTable [i] [1] == key) return KeyTable [i] [0];
  }
  return 0;
}

/**
 * Forces all outstanding paint requests for the display
 * to be processed before this method returns.
 *
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see Control#update
 */
public void update () {
  checkDevice ();
  flushExposes (0, true);
  OS.gdk_window_process_all_updates ();
}

/**
 * If the receiver's user-interface thread was <code>sleep</code>'ing, 
 * causes it to be awakened and start running again. Note that this
 * method may be called from any thread.
 * 
 * @exception SWTException <ul>
 *    <li>ERROR_DEVICE_DISPOSED - if the receiver has been disposed</li>
 * </ul>
 * 
 * @see #sleep
 */
public void wake () {
  if (isDisposed ()) error (SWT.ERROR_DEVICE_DISPOSED);
  if (thread == Thread.currentThread ()) return;
  wakeThread ();
}

void wakeThread () {
  wake = true;
  // NOT IMPLEMENTED - need to wake up the event loop
}

static char wcsToMbcs (char ch) {
  int key = ch & 0xFFFF;
  if (key <= 0x7F) return ch;
  byte [] buffer = Converter.wcsToMbcs (null, new char [] {ch}, false);
  if (buffer.length == 1) return (char) buffer [0];
  if (buffer.length == 2) {
    return (char) (((buffer [0] & 0xFF) << 8) | (buffer [1] & 0xFF));
  }
  return 0;
}

long /*int*/ windowProc (long /*int*/ handle, long /*int*/ user_data) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.windowProc (handle, user_data);
}

long /*int*/ windowProc (long /*int*/ handle, long /*int*/ arg0, long /*int*/ user_data) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.windowProc (handle, arg0, user_data);
}

long /*int*/ windowProc (long /*int*/ handle, long /*int*/ arg0, long /*int*/ arg1, long /*int*/ user_data) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.windowProc (handle, arg0, arg1, user_data);
}

long /*int*/ windowProc (long /*int*/ handle, long /*int*/ arg0, long /*int*/ arg1, long /*int*/ arg2, long /*int*/ user_data) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.windowProc (handle, arg0, arg1, arg2, user_data);
}

long /*int*/ windowTimerProc (long /*int*/ handle) {
  Widget widget = getWidget (handle);
  if (widget == null) return 0;
  return widget.timerProc (handle);
}

}