gtk2/docs/Changes-2.0.txt

Incompatible Changes from GTK+-1.2 to GTK+-2.0:

* gtk_container_get_toplevels() was removed and replaced with
  gtk_window_list_toplevels(), which has different memory management 
  on the return value (gtk_window_list_toplevels() copies the GList
  and also references each widget in the list, so you have to
  g_list_free() the list after first unref'ing each list member).

* The gdk_time* functions have been removed. This functionality
  has been unused since the main loop was moved into GLib
  prior to 1.2. 

* The signature for GtkPrintFunc (used for gtk_item_factory_dump_items)
  has been changed to take a 'const gchar *' instead of 'gchar *', to
  match what we do for glib, and other similar cases.

* The detail arguments in the GtkStyleClass structure are now 'const gchar *'.

* gtk_paned_set_gutter_size() has been removed, since the small handle tab
  has been changed to include the entire area previously occupied by
  the gutter.

* GDK no longer selects OwnerGrabButtonMask for button presses. This means  
  that the automatic grab that occurs when the user presses a button
  will have owner_events = FALSE, so all events are redirected to the
  grab window, even events that would normally go to  other windows of the
  window's owner.

* GtkColorSelectionDialog has now been moved into it's own set of files,
  gtkcolorseldialog.c and gtkcolorseldialog.h.

* gtk_widget_shape_combine_mask() now keeps a reference count on the 
  mask pixmap that is passed in.

* the GtkPatternSpec has been moved to glib as GPatternSpec, the pattern
  arguments to gtk_item_factory_dump_items() and gtk_item_factory_dump_rc()
  have thusly been changed to take a GPatternSpec instead of GtkPatternSpec.
  
* Type system changes:
  - GTK_TYPE_OBJECT is not a fundamental type anymore. Type checks of the
    style (GTK_FUNDAMENTAL_TYPE (some_type) == GTK_TYPE_OBJECT)
    will not work anymore. As a replacement, (GTK_TYPE_IS_OBJECT (some_type))
    can be used now.
  - The following types vanished: GTK_TYPE_ARGS, GTK_TYPE_CALLBACK,
    GTK_TYPE_C_CALLBACK, GTK_TYPE_FOREIGN. The corresponding GtkArg
    fields and field access macros are also gone.
  - The following type aliases vanished: GTK_TYPE_FLAT_FIRST,
    GTK_TYPE_FLAT_LAST, GTK_TYPE_STRUCTURED_FIRST, GTK_TYPE_STRUCTURED_LAST.
  - The type macros GTK_TYPE_MAKE() and GTK_TYPE_SEQNO() vanished, use of
    GTK_FUNDAMENTAL_TYPE() is discouraged. Instead, the corresponding GType
    API should be used: G_TYPE_FUNDAMENTAL(), G_TYPE_DERIVE_ID(),
    G_TYPE_BRANCH_SEQNO(). Note that the GLib type system doesn't build new
    type ids based on a global incremental sequential number anymore, but
    numbers new type ids sequentially per fundamental type branch.
  - The following type functions vanished/were replaced:
    Old Function		 Replacement
    gtk_type_query()		 - being investigated -
    gtk_type_set_varargs_type()	 -
    gtk_type_get_varargs_type()	 -
    gtk_type_check_object_cast() g_type_check_instance_cast()
    gtk_type_check_class_cast()	 g_type_check_class_cast()
    gtk_type_describe_tree()	 -
    gtk_type_describe_heritage() -
    gtk_type_free()		 -
    gtk_type_children_types()	 g_type_children()
    gtk_type_set_chunk_alloc()	 GTypeInfo.n_preallocs
    gtk_type_register_enum()	 g_enum_register_static()
    gtk_type_register_flags()	 g_flags_register_static()
    gtk_type_parent_class()	 g_type_parent() / g_type_class_peek_parent()
    Use of g_type_class_ref() / g_type_class_unref() and g_type_class_peek()
    is recommended over usage of gtk_type_class().
    Use of g_type_register_static() / g_type_register_dynamic() is recommended
    over usage of gtk_type_unique().

* Object system changes:
  GtkObject derives from GObject, so is not the basic object type anymore.
  This imposes the following source incompatible changes:
  - GtkObject has no klass field anymore, an object's class can be retrived
    with the object's coresponding GTK_<OBJECT>_GET_CLASS (object) macro.
  - GtkObjectClass has no type field anymore, a class's type can be retrived
    with the GTK_CLASS_TYPE (class) macro.
  - GtkObjectClass does not introduce the finalize() and shutdown() methods
    anymore. While shutdown() is intended for GTK+ internal use only, finalize()
    is required by a variety of object implementations. GObjectClass.finalize
    should be overriden here, e.g.:
    static void gtk_label_finalize (GObject *gobject)
    {
      GtkLabel *label = GTK_LABEL (gobject);
      
      G_OBJECT_CLASS (parent_class)->finalize (object);
    }
    static void gtk_label_class_init (GtkLabelClass *class)
    {
      GObjectClass *gobject_class = G_OBJECT_CLASS (class);
      
      gobject_class->finalize = gtk_label_finalize;
    }

  - the GtkObject::destroy signal can now be emitted multiple times on an object.
    ::destroy implementations should check that make sure that they take this
    into account, by checking to make sure that resources are there before
    freeing them. For example:
    if (object->foo_data)
      { 
        g_free (object->foo_data);
        object->foo_data = NULL;
      }

    Also, ::destroy implementations have to release object references that
    the object holds. Code in finalize implementations such as:
    if (object->adjustment)
      {
        gtk_object_unref (object->adjustment);
        object->adjustment = NULL;
      }
    have to be moved into the ::destroy implementations. The reason for doing
    this is that all object reference cycles should be broken at destruction 
    time.

    Because the ::destroy signal can be emitted multiple times, it no longer
    makes sense to check if a widget has been destroyed using the 
    GTK_OBJECT_DESTROYED() macro, and this macro has been removed. If 
    catching destruction is still needed, it can be done with a signal
    connection to ::destroy.
    
* Signal system changes:
  The Gtk 2.0 signal merly proxies the GSignal system now.
  For future usage, direct use of the GSignal API is recommended,
  this avoids significant performance hits where GtkArg structures
  have to be converted into GValues. For language bindings,
  GSignal+GClosure provide a much more flexible and convenient
  mechanism to hook into signal emissions or install class default
  handlers, so the old GtkSignal API for language bindings is not
  supported anymore.
  Functions that got removed in the Gtk signal API:
  gtk_signal_n_emissions(), gtk_signal_n_emissions_by_name(),
  gtk_signal_set_funcs(), gtk_signal_handler_pending_by_id(),
  gtk_signal_add_emission_hook(), gtk_signal_add_emission_hook_full(),
  gtk_signal_remove_emission_hook(), gtk_signal_query().
  Also, the GtkCallbackMarshal argument to gtk_signal_connect_full() is
  not supported anymore.
  For many of the removed functions, similar variants are available
  in the g_signal_* namespace.
  The GSignal system perfomrs emissions in a slightly different manner than
  the old GtkSignal code. Signal handlers that are connected to signal "foo"
  on object "bar" while "foo" is being emitted, will not be called anymore
  during the emission they were connected within.

* Inserting and deleting text in GtkEntry though functions such
  as gtk_entry_insert_text() now leave the cursor at its original
  position in the text instead of moving it to the location of
  the insertion/deletion.

* The ->label field of GtkFrame widgets has been removed. (As part of
  a change to allow the arbitrary widgets in the title position.) The
  text can now be retrieved with the new function gtk_frame_get_text().

* The 'font' and 'font_set' declarations in RC files are now ignored. There
  is a new 'font_name' field that holds the string form of a Pango font

* A number of types in GDK have become subclasses of GObject. For the
  most part, this should not break anyone's code. However, it's now 
  possible/encouraged to use g_object_ref()/g_object_unref() and other
  GObject features with these GDK types. The converted types are:
  GdkWindow, GdkDrawable, GdkPixmap, GdkImage, GdkGC, GdkDragContext,
  GdkColormap

* All drawables including pixmaps used to have a type tag, the 
  GdkWindowType enumeration, which included GDK_WINDOW_PIXMAP.
  GdkWindowType is now a property of GdkWindow _only_, and there is
  no GDK_WINDOW_PIXMAP. You can use the GDK_IS_PIXMAP() macro to see 
  if you have a pixmap, if you need to know that.

* GtkStyle and GtkRcStyle are now subclasses of GObject as well.  This
  requires fairly extensive changes to theme engines quite badly, but
  shouldn't affect most other code.

* xthickness/ythickness have moved from GtkStyleClass to GtkStyle
  (from class to instance). This gives themes a bit more flexibility
  and is generally more of the Right Thing. You can trivially fix
  your code with s/style->klass->xthickness/style->xthickness/g and 
  same for ythickness.

* Some GtkStyle draw_ methods have been removed (cross, oval, ramp) 
  and others have been added (expander, layout). This will require
  changes to theme engines.

* If you were using private GDK types, they have been rearranged
  significantly. You shouldn't use private types. ;-) 

* The visual for a widget, and also the default visual is now derived
  from the colormap for the widget and the default colormap. 
  gtk_widget_set_visual(), gtk_widget_set_default_visual(), gtk_widget_push_visual() 
  and gtk_widget_pop_visual() now do nothing. Since the visual always
  had to match that of the colormap, it is safe to simply delete
  all references to these functions.

* A number of functions in GDK have been renamed for consistency and
  clarity. #defines to provide backwards compatibility have been
  included, but can be disabled by defineing GDK_DISABLE_DEPRECATED.

  #define gdk_draw_pixmap                gdk_draw_drawable
  #define gdk_draw_bitmap                gdk_draw_drawable

  #define gdk_window_get_size            gdk_drawable_get_size
  #define gdk_window_get_type            gdk_window_get_window_type
  #define gdk_window_get_colormap        gdk_drawable_get_colormap
  #define gdk_window_set_colormap        gdk_drawable_set_colormap
  #define gdk_window_get_visual          gdk_drawable_get_visual

  #define gdk_window_ref                 gdk_drawable_ref
  #define gdk_window_unref               gdk_drawable_unref
  #define gdk_bitmap_ref                 gdk_drawable_ref
  #define gdk_bitmap_unref               gdk_drawable_unref
  #define gdk_pixmap_ref                 gdk_drawable_ref
  #define gdk_pixmap_unref               gdk_drawable_unref

  #define gdk_gc_destroy                 gdk_gc_unref
  #define gdk_image_destroy              gdk_image_unref
  #define gdk_cursor_destroy             gdk_cursor_unref

  (Note that g_object_ref() and g_object_unref() may be used for all of
  the above _ref and _unref functions.)

  #define gdk_window_copy_area(drawable,gc,x,y,source_drawable,source_x,source_y,width,height) \
     gdk_draw_pixmap(drawable,gc,source_drawable,source_x,source_y,x,y,width,height)

  #define gdk_rgb_get_cmap               gdk_rgb_get_colormap
  
  gtk_widget_popup() was removed, it was only usable for GtkWindows, and
  there the same effect can be achived by gtk_widget_set_uposition() and
  gtk_widget_show().

* gdk_pixmap_foreign_new() no longer calls XFreePixmap() on the 
  pixmap when the GdkPixmap is finalized. This change corresponds
  to the behavior of gdk_window_foreign_new(), and fixes a lot
  of problems with code where the pixmap wasn't supposed to be
  freed. If XFreePixmap() is needed, it can be done using the
  destroy-notification facilities of g_object_set_data().

* GtkProgress/GtkProgressBar had serious problems in GTK 1.2.
  - Only 3 or 4 functions are really needed for 95% of progress  
    interfaces; GtkProgress[Bar] had about 25 functions, and 
    didn't even include these 3 or 4.
  - In activity mode, the API involves setting the adjustment 
    to any random value, just to have the side effect of 
    calling the progress bar update function - the adjustment
    is totally ignored in activity mode
  - You set the activity step as a pixel value, which means to 
    set the activity step you basically need to connect to 
    size_allocate
  - There are ctree_set_expander_style()-functions, to randomly 
    change look-and-feel for no good reason
  - The split between GtkProgress and GtkProgressBar makes no sense 
    to me whatsoever.
  This was a big wart on GTK and made people waste lots of time,
  both learning and using the interface.
  So, we have added what we feel is the correct API, and marked all the
  rest deprecated. However, the changes are 100% backward-compatible and
  should break no existing code.
  The following 5 functions are the new programming interface and you 
  should consider changing your code to use them:
  void       gtk_progress_bar_pulse                (GtkProgressBar *pbar);
  void       gtk_progress_bar_set_text             (GtkProgressBar *pbar,
                                                    const gchar    *text);
  void       gtk_progress_bar_set_fraction         (GtkProgressBar *pbar,
                                                    gfloat          fraction);

  void       gtk_progress_bar_set_pulse_step       (GtkProgressBar *pbar,
                                                    gfloat          fraction);
  void       gtk_progress_bar_set_orientation      (GtkProgressBar *pbar,
						    GtkProgressBarOrientation orientation);

* The GtkNotebookPage structure has been removed from the public header files;
  this was never meant to be a public structure, and all functionality that
  could be done by accessing the struct fields of this structure should be 
  accesible otherwise.

* GtkMenuPositionFunc has a new parameter push_in which controls how
  menus placed outside the screen is handled. If this is set to true and
  part of the menu is outside the screen then Gtk+ pushes it into the visible
  area. Otherwise the menu is cut of at the end of the visible screen area.

  Regardles of what happens to the size of the menu, the result is always
  that the items are placed in the same place as if the menu was placed
  outside the screen, using menu scrolling if necessary.
  
* The "draw" signal and virtual method on GtkWidget has been removed.
  All drawing should now occur by invalidating a region of the widget
  (call gdk_window_invalidate_rect() or gtk_widget_queue_draw() for
  example to invalidate a region). GTK+ merges all invalid regions,
  and sends expose events to the widget in an idle handler for the
  invalid regions. gtk_widget_draw() is deprecated but still works; it
  adds the passed-in area to the invalid region and immediately sends
  expose events for the current invalid region. 
  Most widgets will work fine if you just delete their "draw"
  implementation, since they will already have working expose_event
  implementations. The draw method was rarely called in practice
  anyway.

* The GdkExposeEvent has a new region field. This can be used instead
  of the area field if you want a more exact representation of the
  area to update.

* Sending synthetic exposes using gtk_widget_event is no longer allowed.
  If you just need an expose call you should use gdk_window_invalidate_rect()
  or gdk_window_invalidate_region() instead. For the case of container
  widgets that need to propagate expose events to NO_WINDOW children
  you can either use gtk_container_propagate_expose(), or chain to the
  default container expose handler.
 
* The draw_default and draw_focus methods/signals on GtkWidget are
  gone; simply draw things in your expose handler. 
  gtk_widget_draw_focus() and gtk_widget_draw_default() wrapper
  functions are also gone; just queue a draw on the widget,  
  or the part affected by the focus/default anyway.
  Also, GtkWidget now has default implementations for focus_in_event
  and focus_out_event. These set/unset GTK_HAS_FOCUS, and queue a
  draw. So if your focus in/out handler just does that, you can delete
  it.

* GtkText and GtkTree are buggy and broken. We don't recommend using
  them, and changing old code to avoid them is a good idea. The
  recommended alternatives are GtkTextView and GtkTreeView.  The
  broken widgets are not declared in the headers by default; to use
  them, define the symbol GTK_ENABLE_BROKEN during compilation.  In
  some future release, these widgets will be removed from GTK+.

* GdkColorContext is gone; you probably weren't using it anyway.
  Use GdkColormap and the gdk_rgb_* functions instead.

* GtkMenuBar now draws the GtkContainer::border_width space outside
  the frame, not inside the frame

* In GTK 1.2, if an event handler returned TRUE it prevented
  propagation of that event to parent widgets. That is, the 
  event signal would not be emitted on parent widgets. In 
  GTK 2.0, if an event handler returns TRUE, the current signal 
  emission on the current widget is immediately stopped. That is,
  other callbacks connected to the signal will not be invoked.

* gtk_toolbar_new() no longer has arguments. This function 
  was broken because the default GtkToolbarStyle (icons, text, both)
  is now a user preference, which is overridden when you call
  gtk_toolbar_set_style(). The constructor forced everyone to 
  override the preference, which was undesirable. So to port
  your app, decide if you want to force the toolbar style 
  or conform to the user's global defaults; if you want to force
  it, call gtk_toolbar_set_style().

  The orientation arg was removed from toolbar_new() as well, just
  because it wasn't very useful and we were breaking the function
  anyway so had an opportunity to lose it. Call
  gtk_toolbar_set_orientation() to set toolbar orientation.

* GtkRange/GtkScrollbar/GtkScale were rewritten; this means that most
  theme engines won't draw them properly, and any custom subclasses of
  these widgets will need a rewrite (though if you could figure out
  how to subclass the old version of GtkRange, you have our
  respect). Also, GtkTroughType is gone.

* The GtkContainer::focus signal/virtualfunction and
  gtk_container_focus() call were replaced by 
  GtkWidget::focus and gtk_widget_child_focus(). 
  The semantics are the same, so you should be able to just 
  replace "container_class->focus = mywidget_focus" with 
  "widget_class->focus = mywidget_focus" and replace 
  gtk_container_focus() calls with gtk_widget_child_focus() calls.

  The purpose of this change was to allow non-containers to have 
  focusable elements.
 
* gtk_rc_set_image_loader() and gtk_rc_load_image() has been removed, now 
  that GTK+ includes decent image loading capabilities itself.

* An extra GtkSettings argument has been added to
  gtk_rc_find_pixmap_in_path(). This function is only actually useful
  from a theme engine during parsing, at which point the GtkSettings
  is provided.

* The child argument facility in gtkcontainer.c has been converted
  to a child property facility using GParamSpec and other facilities
  for GObject.   

   - The set_child_arg and get_child_arg virtual methods have been
     replaced with set_child_property / get_child_property, which
     work similar to GObject->set_property/get_property.

   - Other removed functions with the replacements:

     gtk_container_add_child_arg_type => gtk_container_class_install_child_property
     gtk_container_query_child_args   => gtk_container_class_list_child_properties
     gtk_container_child_getv         => gtk_container_child_set_property
     gtk_container_child_setv         => gtk_container_child_get_property
     gtk_container_add_with_args      => gtk_container_add_with_properties
     gtk_container_addv               => gtk_container_add / gtk_container_child_set_property

* gdk_image_get() (or rather its replacement,
  gdk_drawable_get_image()) now handles errors properly by returning
  NULL, previously it would crash. Also, a window being offscreen is
  no longer considered an error; instead, the area being contains
  undefined contents for the offscreen areas. In most cases, code
  using gdk_image_get() should really be ported to
  gdk_pixbuf_get_from_drawable().

* gtk_widget_set_usize() has been renamed to
  gtk_widget_set_size_request(), however the old name still exists
  unless you define GTK_DISABLE_DEPRECATED.

* gtk_widget_set_uposition() is deprecated; use gtk_window_move(), 
  gtk_fixed_put(), or gtk_layout_put() instead.

* gtk_window_set_policy() is deprecated. To get the effect of
  "allow_shrink", call gtk_widget_set_size_request(window, 0, 0).  To
  get the effect of "allow_grow", call
  gtk_window_set_resizable(window, TRUE). You didn't want the effect
  of auto_shrink, it made no sense. But maybe if you were using it you
  want to use gtk_window_resize (window, 1, 1) to snap a window back
  to its minimum size (the 1, 1 will be rounded up to the minimum
  window size).

* The core GTK+ now takes care of handling mapping, unmapping and
  realizing the child widgets of containers in
  gtk_widget_set_parent(). In most cases, this allows container
  implementations to be simplifid by removing the code in add()
  methods to map and realize children. However, there are 
  a couple of things to watch out for here:

   - If the parent is realized before the add() happens, 
     gtk_widget_set_parent_window() must be called before
     gtk_widget_set_parent(), since gtk_widget_set_parent()
     will realize the child.

   - If a container depended on its children not being mapped
     unless it did so itself (for example, GtkNotebook only
     mapped the current page), then the new function
     gtk_widget_set_child_visible() must be called to keep
     widgets that should not be mapped not mapped.

  As part of this change, most containers also will no longer need
  custom implementations of the map() and unmap() virtual
  functions. The only cases where this is necessary are:

   - For !NO_WINDOW widgets, if you create children of widget->window 
     and don't map them in realize() then you must map them
     in map(). [ In almost all cases, you can simply map the
     windows in realize() ]

   - For NO_WINDOW widgets, if you create windows in your realize()
     method, you must map then in map() and unmap them in unmap().

* gtk_widget_set_default_style (), gtk_widget_push_style (),
  and gtk_widget_pop_style () have been removed, since they
  did not work properly with themes and there were better
  alternatives for modifying the appearance of widgets.

  You should generally use gtk_widget_modify_fg/bg/base/text/font
  instead.
  
* gtk_image_new() now takes no arguments and creates an empty GtkImage
  widget. To create a GtkImage widget from a GdkImage (the least
  common usage of GdkImage), use gtk_image_new_from_image.

* GTK_SELECTION_EXTENDED is now deprecated, and neither the
  GtkList/GtkTree nor the GtkCList/GtkCTree support
  GTK_SELECTION_EXTENDED anymore.  However, the old extended behavior
  replaces MULTIPLE behavior.

* The following variables are no longer exported from GDK. (Other variables
  are also no longer exported; the following are the ones found used
  externally in a large sample of GTK+ code.)

   Variable                               Replacement
   ========                               ===========
   gdk_null_window_warnings               None - did nothing in GTK+-1.2.
   gdk_leader_window                      None - private variable
   gdk_screen                             gdk_x11_get_default_screen ()
   gdk_root_window                        gdk_x11_get_default_root_xwindow ()
   gdk_root_parent                        gdk_get_default_root_window ()
   gdk_error_code/gdk_error_warnings      gdk_error_trap_push()/pop()
   gdk_display_name                       gdk_get_display ()
   gdk_wm_delete_window                   gdk_atom_intern ("WM_DELETE_WINDOW", FALSE)
   gdk_wm_take_focus                      gdk_atom_intern ("WM_TAKE_FOCUS", FALSE)
   gdk_wm_protocols                       gdk_atom_intern ("WM_PROTOCOLS", FALSE)
   
* The handling of Colormaps and widgets has been changed:

    - The default colormap for widgets is now the GdkRGB colormap, not
      the system default colormap. If you try to use resources created for  
      a widget (e.g., widget->style) with a window using the system
      colormap, errors will result on some machines.

    - gtk_widget_push/pop_colormap() only cause the colormap to be
      explicitely set on toplevel widgets not on all widgets. The
      colormap for other widgets (when not set using 
      gtk_widget_set_colormap()), is determined by finding the nearest
      ancestor with a colormap set on it explicitely, or if that
      fails, the default colormap.

* The default selected day for GtkCalendar is now the current day in the
  month, not the first day in the month. The current month and year
  were already used.

* GDK is no longer put into threaded mode automatically when 
  g_thread_init() has been called. In order to use the 
  global GDK thread mutex with gdk_threads_enter() and 
  gdk_threads_leave(), you must call gdk_threads_init() explicitely.

  If you aren't using GDK and GTK+ functions from multiple threads,
  there is no reason to call gdk_threads_init().

* The GtkPreviewInfo struct has had its visual and colormap fields
  removed.  Also, gtk_preview_get_cmap() and gtk_preview_get_visual()
  are deprecated, as GdkRgb works on any colormap and visual.  You no
  longer need to gtk_widget_push_cmap (gtk_preview_get_cmap ()) in
  your code.

* The GtkBox, GtkTable, and GtkAlignment widgets now call
  gtk_widget_set_redraw_on_allocate (widget, FALSE); on themselves.
  If you want to actually draw contents in a widget derived from
  one of these widgets, you'll probably want to change this
  in your init() function.

* A number of widgets are now NO_WINDOW widgets (most importantly
  GtkButton, but also GtkRange and GtkNotebook)

  This has a couple of effects:

   - If you are deriving from one of these widgets, you need to
     adapt your code appropriately -- for instance, drawing coordinates
     start from widget->allocation.x, widget->allocation.y.

   - If you are embedding one of these widgets in a custom widget,
     you must make sure you call gtk_container_propagate_expose()
     correctly, as you must for any NO_WINDOW widgets.

  GtkFixed is a little special; it is now created by default as
  a NO_WINDOW widget, but if you do 

    gtk_fixed_set_has_window (fixed, TRUE);

  after creating a fixed widget, it will create a window and
  handle it properly.

* GtkLayout no longer has the xoffset, yoffset fields, which used
  to store the difference between world and window coordinates for
  layout->bin_window. These coordinate systems are now always
  the same.

* gtk_paint_focus(), gtk_draw_focus() and GtkStyle::draw_focus()
  have been changed a bit:

   - A GtkStateType argument has been added to gtk_paint_focus()
   - The default implementation of GtkStyle::draw_focus virtual
     function now draws a focus rectangle whose width is 
     determinted by the GtkWidget::focus-width style property.
   - The rectangle passed in is the bounding box, instead of
     the rectangle used in the gdk_draw_rectangle() call, so it is
     no longer necessary to subtract 1 from the width and height.