gtk/gdk/gdkwindow.c

/* GDK - The GIMP Drawing Kit
 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

/*
 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

#include "gdkwindow.h"
#include "gdkinternals.h"
#include "gdk.h"		/* For gdk_rectangle_union() */
#include "gdkpixmap.h"
#include "gdkdrawable.h"
#include "gdkpixmap.h"

#define USE_BACKING_STORE	/* Appears to work on Win32, too, now. */

typedef struct _GdkWindowPaint GdkWindowPaint;

struct _GdkWindowPaint
{
  GdkRegion *region;
  GdkPixmap *pixmap;
  gint x_offset;
  gint y_offset;
};

static const GdkPointerHooks default_pointer_hooks = {
  _gdk_windowing_window_get_pointer,
  _gdk_windowing_window_at_pointer
};

static const GdkPointerHooks *current_pointer_hooks = &default_pointer_hooks;

static GdkGC *gdk_window_create_gc      (GdkDrawable     *drawable,
                                         GdkGCValues     *values,
                                         GdkGCValuesMask  mask);
static void   gdk_window_draw_rectangle (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         gint             filled,
                                         gint             x,
                                         gint             y,
                                         gint             width,
                                         gint             height);
static void   gdk_window_draw_arc       (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         gint             filled,
                                         gint             x,
                                         gint             y,
                                         gint             width,
                                         gint             height,
                                         gint             angle1,
                                         gint             angle2);
static void   gdk_window_draw_polygon   (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         gint             filled,
                                         GdkPoint        *points,
                                         gint             npoints);
static void   gdk_window_draw_text      (GdkDrawable     *drawable,
                                         GdkFont         *font,
                                         GdkGC           *gc,
                                         gint             x,
                                         gint             y,
                                         const gchar     *text,
                                         gint             text_length);
static void   gdk_window_draw_text_wc   (GdkDrawable     *drawable,
                                         GdkFont         *font,
                                         GdkGC           *gc,
                                         gint             x,
                                         gint             y,
                                         const GdkWChar  *text,
                                         gint             text_length);
static void   gdk_window_draw_drawable  (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         GdkPixmap       *src,
                                         gint             xsrc,
                                         gint             ysrc,
                                         gint             xdest,
                                         gint             ydest,
                                         gint             width,
                                         gint             height);
static void   gdk_window_draw_points    (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         GdkPoint        *points,
                                         gint             npoints);
static void   gdk_window_draw_segments  (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         GdkSegment      *segs,
                                         gint             nsegs);
static void   gdk_window_draw_lines     (GdkDrawable     *drawable,
					 GdkGC           *gc,
					 GdkPoint        *points,
					 gint             npoints);
static void   gdk_window_draw_glyphs    (GdkDrawable      *drawable,
					 GdkGC            *gc,
					 PangoFont        *font,
					 gint              x,
					 gint              y,
					 PangoGlyphString *glyphs);

static void   gdk_window_draw_image     (GdkDrawable     *drawable,
                                         GdkGC           *gc,
                                         GdkImage        *image,
                                         gint             xsrc,
                                         gint             ysrc,
                                         gint             xdest,
                                         gint             ydest,
                                         gint             width,
                                         gint             height);

static GdkImage*  gdk_window_get_image  (GdkDrawable     *drawable,
                                         gint             x,
                                         gint             y,
                                         gint             width,
                                         gint             height);


static void   gdk_window_real_get_size  (GdkDrawable     *drawable,
                                         gint            *width,
                                         gint            *height);

static GdkVisual*   gdk_window_real_get_visual   (GdkDrawable *drawable);
static gint         gdk_window_real_get_depth    (GdkDrawable *drawable);
static void         gdk_window_real_set_colormap (GdkDrawable *drawable,
                                             GdkColormap *cmap);
static GdkColormap* gdk_window_real_get_colormap (GdkDrawable *drawable);

static GdkDrawable* gdk_window_get_composite_drawable (GdkDrawable *drawable,
						       gint         x,
						       gint         y,
						       gint         width,
						       gint         height,
						       gint        *composite_x_offset,
						       gint        *composite_y_offset);
static GdkRegion*   gdk_window_get_clip_region        (GdkDrawable *drawable);
static GdkRegion*   gdk_window_get_visible_region     (GdkDrawable *drawable);

static void gdk_window_free_paint_stack (GdkWindow *window);

static void gdk_window_init       (GdkWindowObject      *window);
static void gdk_window_class_init (GdkWindowObjectClass *klass);
static void gdk_window_finalize   (GObject              *object);

static gpointer parent_class = NULL;

GType
gdk_window_object_get_type (void)
{
  static GType object_type = 0;

  if (!object_type)
    {
      static const GTypeInfo object_info =
      {
        sizeof (GdkWindowObjectClass),
        (GBaseInitFunc) NULL,
        (GBaseFinalizeFunc) NULL,
        (GClassInitFunc) gdk_window_class_init,
        NULL,           /* class_finalize */
        NULL,           /* class_data */
        sizeof (GdkWindowObject),
        0,              /* n_preallocs */
        (GInstanceInitFunc) gdk_window_init,
      };
      
      object_type = g_type_register_static (GDK_TYPE_DRAWABLE,
                                            "GdkWindow",
                                            &object_info, 0);
    }
  
  return object_type;
}

static void
gdk_window_init (GdkWindowObject *window)
{
  /* 0-initialization is good for all other fields. */

  window->window_type = GDK_WINDOW_CHILD;

  window->state = GDK_WINDOW_STATE_WITHDRAWN;
  
  window->impl = g_object_new (_gdk_window_impl_get_type (), NULL);
}

static void
gdk_window_class_init (GdkWindowObjectClass *klass)
{
  GObjectClass *object_class = G_OBJECT_CLASS (klass);
  GdkDrawableClass *drawable_class = GDK_DRAWABLE_CLASS (klass);
  
  parent_class = g_type_class_peek_parent (klass);

  object_class->finalize = gdk_window_finalize;

  drawable_class->create_gc = gdk_window_create_gc;
  drawable_class->draw_rectangle = gdk_window_draw_rectangle;
  drawable_class->draw_arc = gdk_window_draw_arc;
  drawable_class->draw_polygon = gdk_window_draw_polygon;
  drawable_class->draw_text = gdk_window_draw_text;
  drawable_class->draw_text_wc = gdk_window_draw_text_wc;
  drawable_class->draw_drawable = gdk_window_draw_drawable;
  drawable_class->draw_points = gdk_window_draw_points;
  drawable_class->draw_segments = gdk_window_draw_segments;
  drawable_class->draw_lines = gdk_window_draw_lines;
  drawable_class->draw_glyphs = gdk_window_draw_glyphs;
  drawable_class->draw_image = gdk_window_draw_image;
  drawable_class->get_depth = gdk_window_real_get_depth;
  drawable_class->get_size = gdk_window_real_get_size;
  drawable_class->set_colormap = gdk_window_real_set_colormap;
  drawable_class->get_colormap = gdk_window_real_get_colormap;
  drawable_class->get_visual = gdk_window_real_get_visual;
  drawable_class->get_image = gdk_window_get_image;
  drawable_class->get_clip_region = gdk_window_get_clip_region;
  drawable_class->get_visible_region = gdk_window_get_visible_region;
  drawable_class->get_composite_drawable = gdk_window_get_composite_drawable;
}

static void
gdk_window_finalize (GObject *object)
{
  GdkWindow *window = GDK_WINDOW (object);
  GdkWindowObject *obj = (GdkWindowObject *) object;
  
  if (!GDK_WINDOW_DESTROYED (window))
    {
      if (GDK_WINDOW_TYPE (window) != GDK_WINDOW_FOREIGN)
	{
	  g_warning ("losing last reference to undestroyed window\n");
	  _gdk_window_destroy (window, FALSE);
	}
      else
	/* We use TRUE here, to keep us from actually calling
	 * XDestroyWindow() on the window
	 */
	_gdk_window_destroy (window, TRUE);
    }

  g_object_unref (G_OBJECT (obj->impl));
  obj->impl = NULL;
  
  G_OBJECT_CLASS (parent_class)->finalize (object);
}

/**
 * _gdk_window_destroy_hierarchy:
 * @window: a #GdkWindow
 * @recursing: If TRUE, then this is being called because a parent
 *            was destroyed. This generally means that the call to the windowing system
 *            to destroy the window can be omitted, since it will be destroyed as a result
 *            of the parent being destroyed. Unless @foreign_destroy
 *            
 * foreign_destroy: If TRUE, the window or a parent was destroyed by some external 
 *            agency. The window has already been destroyed and no windowing
 *            system calls should be made. (This may never happen for some
 *            windowing systems.)
 *
 * Internal function to destroy a window. Like gdk_window_destroy(), but does not
 * drop the reference count created by gdk_window_new().
 **/
static void
_gdk_window_destroy_hierarchy (GdkWindow *window,
			       gboolean   recursing,
			       gboolean   foreign_destroy)
{
  GdkWindowObject *private;
  GdkWindowObject *temp_private;
  GdkWindow *temp_window;
  GList *children;
  GList *tmp;
  
  g_return_if_fail (window != NULL);
  
  private = (GdkWindowObject*) window;
  
  switch (GDK_WINDOW_TYPE (window))
    {
    case GDK_WINDOW_TOPLEVEL:
    case GDK_WINDOW_CHILD:
    case GDK_WINDOW_DIALOG:
    case GDK_WINDOW_TEMP:
    case GDK_WINDOW_FOREIGN:
      if (!GDK_WINDOW_DESTROYED (window))
	{
	  private->state |= GDK_WINDOW_STATE_WITHDRAWN;
	  
	  if (private->parent)
	    {
	      GdkWindowObject *parent_private = (GdkWindowObject *)private->parent;
	      if (parent_private->children)
		parent_private->children = g_list_remove (parent_private->children, window);
	    }

	  _gdk_window_clear_update_area (window);
	  gdk_window_free_paint_stack (window);
	  
	  if (private->bg_pixmap &&
              private->bg_pixmap != GDK_PARENT_RELATIVE_BG &&
              private->bg_pixmap != GDK_NO_BG)
	    {
	      gdk_pixmap_unref (private->bg_pixmap);
	      private->bg_pixmap = NULL;
	    }
	  
	  if (GDK_WINDOW_TYPE (window) != GDK_WINDOW_FOREIGN)
	    {
	      children = tmp = private->children;
	      private->children = NULL;
	      
	      while (tmp)
		{
		  temp_window = tmp->data;
		  tmp = tmp->next;
		  
		  temp_private = (GdkWindowObject*) temp_window;
		  if (temp_private)
		    _gdk_window_destroy_hierarchy (temp_window, TRUE, foreign_destroy);
		}
	      
	      g_list_free (children);
	    }
	  
	  _gdk_windowing_window_destroy (window, recursing, foreign_destroy);
	  private->destroyed = TRUE;

	  if (private->filters)
	    {
	      tmp = private->filters;
	      
	      while (tmp)
		{
		  g_free (tmp->data);
		  tmp = tmp->next;
		}
	      
	      g_list_free (private->filters);
	      private->filters = NULL;
	    }

          gdk_drawable_set_colormap (GDK_DRAWABLE (window), NULL);
	}
      break;
      
    case GDK_WINDOW_ROOT:
      g_error ("attempted to destroy root window");
      break;
    }
}

/**
 * _gdk_window_destroy:
 * @window: a #GdkWindow
 * foreign_destroy: If TRUE, the window or a parent was destroyed by some external 
 *            agency. The window has already been destroyed and no windowing
 *            system calls should be made. (This may never happen for some
 *            windowing systems.)
 *
 * Internal function to destroy a window. Like gdk_window_destroy(), but does not
 * drop the reference count created by gdk_window_new().
 **/
void
_gdk_window_destroy (GdkWindow *window,
		     gboolean   foreign_destroy)
{
  _gdk_window_destroy_hierarchy (window, FALSE, foreign_destroy);
}

void
gdk_window_destroy (GdkWindow *window)
{
  _gdk_window_destroy_hierarchy (window, FALSE, FALSE);
  gdk_drawable_unref (window);
}

void
gdk_window_set_user_data (GdkWindow *window,
			  gpointer   user_data)
{
  g_return_if_fail (window != NULL);
  
  ((GdkWindowObject*)window)->user_data = user_data;
}

void
gdk_window_get_user_data (GdkWindow *window,
			  gpointer  *data)
{
  g_return_if_fail (window != NULL);
  
  *data = ((GdkWindowObject*)window)->user_data;
}

GdkWindowType
gdk_window_get_window_type (GdkWindow *window)
{
  g_return_val_if_fail (GDK_IS_WINDOW (window), (GdkWindowType) -1);
  
  return GDK_WINDOW_TYPE (window);
}

void
gdk_window_get_position (GdkWindow *window,
			 gint      *x,
			 gint      *y)
{
  GdkWindowObject *obj;
  
  g_return_if_fail (GDK_IS_WINDOW (window));
  
  obj = (GdkWindowObject*) window;
  
  if (x)
    *x = obj->x;
  if (y)
    *y = obj->y;
}

GdkWindow*
gdk_window_get_parent (GdkWindow *window)
{
  g_return_val_if_fail (GDK_IS_WINDOW (window), NULL);
  
  return (GdkWindow*) ((GdkWindowObject*) window)->parent;
}

GdkWindow*
gdk_window_get_toplevel (GdkWindow *window)
{
  GdkWindowObject *obj;
  
  g_return_val_if_fail (GDK_IS_WINDOW (window), NULL);

  obj = (GdkWindowObject *)window;
  while (GDK_WINDOW_TYPE (obj) == GDK_WINDOW_CHILD)
    obj = (GdkWindowObject *)obj->parent;
  
  return GDK_WINDOW (obj);
}

GList*
gdk_window_get_children (GdkWindow *window)
{
  g_return_val_if_fail (GDK_IS_WINDOW (window), NULL);

  if (GDK_WINDOW_DESTROYED (window))
    return NULL;

  return g_list_copy (GDK_WINDOW_OBJECT (window)->children);
}

GList *
gdk_window_peek_children (GdkWindow       *window)
{
  g_return_val_if_fail (GDK_IS_WINDOW (window), NULL);

  if (GDK_WINDOW_DESTROYED (window))
    return NULL;

  return GDK_WINDOW_OBJECT (window)->children;
}

void          
gdk_window_add_filter (GdkWindow     *window,
		       GdkFilterFunc  function,
		       gpointer       data)
{
  GdkWindowObject *private;
  GList *tmp_list;
  GdkEventFilter *filter;
  
  g_return_if_fail (window == NULL || GDK_IS_WINDOW (window));

  private = (GdkWindowObject*) window;
  if (private && GDK_WINDOW_DESTROYED (window))
    return;
  
  if (private)
    tmp_list = private->filters;
  else
    tmp_list = _gdk_default_filters;
  
  while (tmp_list)
    {
      filter = (GdkEventFilter *)tmp_list->data;
      if ((filter->function == function) && (filter->data == data))
	return;
      tmp_list = tmp_list->next;
    }
  
  filter = g_new (GdkEventFilter, 1);
  filter->function = function;
  filter->data = data;
  
  if (private)
    private->filters = g_list_append (private->filters, filter);
  else
    _gdk_default_filters = g_list_append (_gdk_default_filters, filter);
}

void
gdk_window_remove_filter (GdkWindow     *window,
			  GdkFilterFunc  function,
			  gpointer       data)
{
  GdkWindowObject *private;
  GList *tmp_list, *node;
  GdkEventFilter *filter;
  
  g_return_if_fail (window == NULL || GDK_IS_WINDOW (window));

  private = (GdkWindowObject*) window;
  
  if (private)
    tmp_list = private->filters;
  else
    tmp_list = _gdk_default_filters;
  
  while (tmp_list)
    {
      filter = (GdkEventFilter *)tmp_list->data;
      node = tmp_list;
      tmp_list = tmp_list->next;
      
      if ((filter->function == function) && (filter->data == data))
	{
	  if (private)
	    private->filters = g_list_remove_link (private->filters, node);
	  else
	    _gdk_default_filters = g_list_remove_link (_gdk_default_filters, node);
	  g_list_free_1 (node);
	  g_free (filter);
	  
	  return;
	}
    }
}

GList *
gdk_window_get_toplevels (void)
{
  GList *new_list = NULL;
  GList *tmp_list;
  
  tmp_list = ((GdkWindowObject *)_gdk_parent_root)->children;
  while (tmp_list)
    {
      new_list = g_list_prepend (new_list, tmp_list->data);
      tmp_list = tmp_list->next;
    }
  
  return new_list;
}

/*************************************************************
 * gdk_window_is_visible:
 *     Check if the given window is mapped.
 *   arguments:
 *     window: 
 *   results:
 *     is the window mapped
 *************************************************************/

gboolean 
gdk_window_is_visible (GdkWindow *window)
{
  g_return_val_if_fail (GDK_IS_WINDOW (window), FALSE);
  
  return GDK_WINDOW_IS_MAPPED (window);
}

/*************************************************************
 * gdk_window_is_viewable:
 *     Check if the window and all ancestors of the window
 *     are mapped. (This is not necessarily "viewable" in
 *     the X sense, since we only check as far as we have
 *     GDK window parents, not to the root window)
 *   arguments:
 *     window:
 *   results:
 *     is the window viewable
 *************************************************************/

gboolean 
gdk_window_is_viewable (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  
  g_return_val_if_fail (window != NULL, FALSE);
  g_return_val_if_fail (GDK_IS_WINDOW (window), FALSE);
  
  while (private && 
	 (private != (GdkWindowObject *)_gdk_parent_root) &&
	 (GDK_WINDOW_TYPE (private) != GDK_WINDOW_FOREIGN))
    {
      if (!GDK_WINDOW_IS_MAPPED (window))
	return FALSE;
      
      private = (GdkWindowObject *)private->parent;
    }
  
  return TRUE;
}

/**
 * gdk_window_get_state:
 * @window: a #GdkWindow
 * 
 * Gets the bitwise OR of the currently active window state flags,
 * from the #GdkWindowState enumeration.
 * 
 * Return value: window state bitfield
 **/
GdkWindowState
gdk_window_get_state (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  
  g_return_val_if_fail (GDK_IS_WINDOW (window), FALSE);
  
  return private->state;
}

/**
 * gdk_window_begin_paint_rect:
 * @window: a #GdkWindow
 * @rectangle: rectangle you intend to draw to
 *
 * A convenience wrapper around gdk_window_begin_paint_region() which
 * creates a rectangular region for you. See
 * gdk_window_begin_paint_region() for details.
 * 
 **/
void
gdk_window_begin_paint_rect (GdkWindow    *window,
			     GdkRectangle *rectangle)
{
  GdkRegion *region;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  region = gdk_region_rectangle (rectangle);
  gdk_window_begin_paint_region (window, region);
  gdk_region_destroy (region);
}

static GdkGC *
gdk_window_get_bg_gc (GdkWindow *window, GdkWindowPaint *paint)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  guint gc_mask = 0;
  GdkGCValues gc_values;

  if (private->bg_pixmap == GDK_PARENT_RELATIVE_BG && private->parent)
    {
      GdkWindowPaint tmp_paint = *paint;
      tmp_paint.x_offset += private->x;
      tmp_paint.y_offset += private->y;
      
      return gdk_window_get_bg_gc (GDK_WINDOW (private->parent), &tmp_paint);
    }
  else if (private->bg_pixmap && private->bg_pixmap != GDK_PARENT_RELATIVE_BG && private->bg_pixmap != GDK_NO_BG)
    {
      gc_values.fill = GDK_TILED;
      gc_values.tile = private->bg_pixmap;
      gc_values.ts_x_origin = - paint->x_offset;
      gc_values.ts_y_origin = - paint->y_offset;
      
      gc_mask = GDK_GC_FILL | GDK_GC_TILE | GDK_GC_TS_X_ORIGIN | GDK_GC_TS_Y_ORIGIN;
    }
  else
    {
      gc_values.foreground = private->bg_color;
      gc_mask = GDK_GC_FOREGROUND;
    }

  return gdk_gc_new_with_values (paint->pixmap, &gc_values, gc_mask);
}

static void
gdk_window_paint_init_bg (GdkWindow      *window,
			  GdkWindowPaint *paint,
			  GdkRegion      *init_region)
{
  GdkGC *tmp_gc;
  
  tmp_gc = gdk_window_get_bg_gc (window, paint);

  gdk_region_offset (init_region,
                     - paint->x_offset,
                     - paint->y_offset);
  gdk_gc_set_clip_region (tmp_gc, init_region);

  gdk_draw_rectangle (paint->pixmap, tmp_gc, TRUE, 0, 0, -1, -1);
  gdk_gc_unref (tmp_gc);
}

#ifdef GDK_WINDOWING_X11
#include "x11/gdkx.h"
#endif

/**
 * gdk_window_begin_paint_region:
 * @window: a #GdkWindow
 * @region: region you intend to draw to
 *
 * Indicates that you are beginning the process of redrawing @region.
 * A backing store (offscreen buffer) large enough to contain @region
 * will be created. The backing store will be initialized with the
 * background color or background pixmap for @window. Then, all
 * drawing operations performed on @window will be diverted to the
 * backing store.  When you call gdk_window_end_paint(), the backing
 * store will be copied to @window, making it visible onscreen. Only
 * the part of @window contained in @region will be modified; that is,
 * drawing operations are clipped to @region.
 *
 * The net result of all this is to remove flicker, because the user
 * sees the finished product appear all at once when you call
 * gdk_window_end_paint(). If you draw to @window directly without
 * calling gdk_window_begin_paint_region(), the user may see flicker
 * as individual drawing operations are performed in sequence.  The
 * clipping and background-initializing features of
 * gdk_window_begin_paint_region() are conveniences for the
 * programmer, so you can avoid doing that work yourself.
 *
 * When using GTK+, the widget system automatically places calls to
 * gdk_window_begin_paint_region() and gdk_window_end_paint() around
 * emissions of the expose_event signal. That is, if you're writing an
 * expose event handler, you can assume that the exposed area in
 * #GdkEventExpose has already been cleared to the window background,
 * is already set as the clip region, and already has a backing store.
 * Therefore in most cases, application code need not call
 * gdk_window_begin_paint_region(). (You can disable the automatic
 * calls around expose events on a widget-by-widget basis by calling
 * gtk_widget_set_double_buffered().)
 *
 * If you call this function multiple times before calling the
 * matching gdk_window_end_paint(), the backing stores are pushed onto
 * a stack. gdk_window_end_paint() copies the topmost backing store
 * onscreen, subtracts the topmost region from all other regions in
 * the stack, and pops the stack. All drawing operations affect only
 * the topmost backing store in the stack. One matching call to
 * gdk_window_end_paint() is required for each call to
 * gdk_window_begin_paint_region().
 * 
 **/
void	      
gdk_window_begin_paint_region (GdkWindow *window,
			       GdkRegion *region)
{
#ifdef USE_BACKING_STORE
  GdkWindowObject *private = (GdkWindowObject *)window;
  GdkRectangle clip_box;
  GdkWindowPaint *paint;
  GdkRegion *init_region;
  GdkGC *tmp_gc;
  
  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  if (GDK_WINDOW_DESTROYED (window))
    return;
  
  paint = g_new (GdkWindowPaint, 1);

  paint->region = gdk_region_copy (region);

  init_region = gdk_region_copy (region);
  gdk_region_get_clipbox (paint->region, &clip_box);

  if (private->paint_stack)
    {
      gint old_width, old_height;
      GdkWindowPaint *tmp_paint = private->paint_stack->data;
      GdkRectangle old_rect, new_rect;
      GSList *tmp_list;

      gdk_drawable_get_size (tmp_paint->pixmap, &old_width, &old_height);
      old_rect.x = tmp_paint->x_offset;
      old_rect.y = tmp_paint->y_offset;
      old_rect.width = old_width;
      old_rect.height = old_height;

      gdk_rectangle_union (&clip_box, &old_rect, &new_rect);

      if (new_rect.width > old_rect.width || new_rect.height > old_rect.height)
	{
	  paint->pixmap = gdk_pixmap_new (window,
                                          new_rect.width, new_rect.height, -1);
          tmp_gc = gdk_gc_new (paint->pixmap);
	  gdk_draw_drawable (paint->pixmap, tmp_gc, tmp_paint->pixmap,
			     0, 0,
			     old_rect.x - new_rect.x, old_rect.y - new_rect.y,
                             old_rect.width, old_rect.height);
          gdk_gc_unref (tmp_gc);
	  gdk_drawable_unref (tmp_paint->pixmap);

	  paint->x_offset = new_rect.x;
	  paint->y_offset = new_rect.y;
	  
	  tmp_list = private->paint_stack;
	  while (tmp_list)
	    {
	      tmp_paint = tmp_list->data;
	      gdk_region_subtract (init_region, tmp_paint->region);

	      tmp_paint->pixmap = paint->pixmap;
	      tmp_paint->x_offset = paint->x_offset;
	      tmp_paint->y_offset = paint->y_offset;
              
	      tmp_list = tmp_list->next;
	    }
	}
      else
	{
	  paint->x_offset = tmp_paint->x_offset;
	  paint->y_offset = tmp_paint->y_offset;
	  paint->pixmap = tmp_paint->pixmap;

	  tmp_list = private->paint_stack;
	  while (tmp_list)
	    {
	      tmp_paint = tmp_list->data;
	      gdk_region_subtract (init_region, tmp_paint->region);

	      tmp_list = tmp_list->next;
	    }
	}
    }
  else
    {
      paint->x_offset = clip_box.x;
      paint->y_offset = clip_box.y;
      paint->pixmap = gdk_pixmap_new (window, clip_box.width, clip_box.height, -1);
    }

  if (!gdk_region_empty (init_region))
    gdk_window_paint_init_bg (window, paint, init_region);
  
  gdk_region_destroy (init_region);
  
  private->paint_stack = g_slist_prepend (private->paint_stack, paint);
#endif /* USE_BACKING_STORE */
}

/**
 * gdk_window_end_paint:
 * @window: a #GdkWindow
 *
 * Indicates that the backing store created by the most recent call to
 * gdk_window_begin_paint_region() should be copied onscreen and
 * deleted, leaving the next-most-recent backing store or no backing
 * store at all as the active paint region. See
 * gdk_window_begin_paint_region() for full details. It is an error to
 * call this function without a matching
 * gdk_window_begin_paint_region() first.
 * 
 **/
void
gdk_window_end_paint (GdkWindow *window)
{
#ifdef USE_BACKING_STORE
  GdkWindowObject *private = (GdkWindowObject *)window;
  GdkWindowPaint *paint;
  GdkGC *tmp_gc;
  GdkRectangle clip_box;
  gint x_offset, y_offset;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  if (GDK_WINDOW_DESTROYED (window))
    return;

  if (private->paint_stack == NULL)
    {
      g_warning (G_STRLOC": no preceding call to gdk_window_begin_paint_region(), see documentation");
      return;
    }

  paint = private->paint_stack->data;
  private->paint_stack = g_slist_delete_link (private->paint_stack, private->paint_stack);

  gdk_region_get_clipbox (paint->region, &clip_box);

  tmp_gc = gdk_gc_new (window);

  _gdk_windowing_window_get_offsets (window, &x_offset, &y_offset);

  gdk_gc_set_clip_region (tmp_gc, paint->region);
  gdk_gc_set_clip_origin (tmp_gc, -x_offset, -y_offset);

  gdk_draw_drawable (private->impl, tmp_gc, paint->pixmap,
                     clip_box.x - paint->x_offset,
                     clip_box.y - paint->y_offset,
                     clip_box.x - x_offset, clip_box.y - y_offset,
                     clip_box.width, clip_box.height);
  gdk_gc_unref (tmp_gc);

  if (private->paint_stack)
    {
      GSList *tmp_list = private->paint_stack;
      while (tmp_list)
	{
	  GdkWindowPaint *tmp_paint = tmp_list->data;
	  gdk_region_subtract (tmp_paint->region, paint->region);
          
	  tmp_list = tmp_list->next;
	}
    }
  else
    gdk_drawable_unref (paint->pixmap);

  gdk_region_destroy (paint->region);
  g_free (paint);
#endif /* USE_BACKING_STORE */
}

static void
gdk_window_free_paint_stack (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  
  if (private->paint_stack)
    {
      GSList *tmp_list = private->paint_stack;

      while (tmp_list)
	{
	  GdkWindowPaint *paint = tmp_list->data;

	  if (tmp_list == private->paint_stack)
	    gdk_drawable_unref (paint->pixmap);
		  
	  gdk_region_destroy (paint->region);
	  g_free (paint);

	  tmp_list = tmp_list->next;
	}

      g_slist_free (private->paint_stack);
      private->paint_stack = NULL;
    }
}

static void
gdk_window_get_offsets (GdkWindow *window,
			gint      *x_offset,
			gint      *y_offset)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      *x_offset = paint->x_offset;
      *y_offset = paint->y_offset;
    }
  else
    _gdk_windowing_window_get_offsets (window, x_offset, y_offset);
}

/**
 * gdk_window_get_internal_paint_info:
 * @window: a #GdkWindow
 * @real_drawable: location to store the drawable to which drawing should be done.
 * @x_offset: location to store the X offset between coordinates in @window, and
 *            the underlying window system primitive coordinates for *@real_drawable.
 * @y_offset: location to store the Y offset between coordinates in @window, and
 *            the underlying window system primitive coordinates for *@real_drawable.
 * 
 * If you bypass the GDK layer and use windowing system primitives to
 * draw directly onto a #GdkWindow, then you need to deal with two
 * details: there may be an offset between GDK coordinates and windowing
 * system coordinates, and GDK may have redirected drawing to a offscreen
 * pixmap as the result of a gdk_window_begin_paint_region() calls.
 * This function allows retrieving the information you need to compensate
 * for these effects.
 *
 * This function exposes details of the GDK implementation, and is thus
 * likely to change in future releases of GDK.
 **/
void
gdk_window_get_internal_paint_info (GdkWindow    *window,
				    GdkDrawable **real_drawable,
				    gint         *x_offset,
				    gint         *y_offset)
{
  gint x_off, y_off;
  
  GdkWindowObject *private;

  g_return_if_fail (GDK_IS_WINDOW (window));

  private = (GdkWindowObject *)window;

  if (real_drawable)
    {
      if (private->paint_stack)
	{
	  GdkWindowPaint *paint = private->paint_stack->data;
	  *real_drawable = paint->pixmap;
	}
      else
	*real_drawable = window;
    }

  gdk_window_get_offsets (window, &x_off, &y_off);

  if (x_offset)
    *x_offset = x_off;
  if (y_offset)
    *y_offset = y_off;
}

#define OFFSET_GC(gc)                                         \
    gint x_offset, y_offset; 				      \
    gint old_clip_x = gc->clip_x_origin;    \
    gint old_clip_y = gc->clip_y_origin;    \
    gint old_ts_x = gc->ts_x_origin;        \
    gint old_ts_y = gc->ts_y_origin;        \
    gdk_window_get_offsets (drawable, &x_offset, &y_offset);  \
    if (x_offset != 0 || y_offset != 0)             	      \
      {                                                       \
        gdk_gc_set_clip_origin (gc, old_clip_x - x_offset,    \
	  	                old_clip_y - y_offset);       \
        gdk_gc_set_ts_origin (gc, old_ts_x - x_offset,        \
	  	              old_ts_y - y_offset);           \
      }

#define RESTORE_GC(gc)                                      \
    if (x_offset != 0 || y_offset != 0)       		    \
     {                                                      \
       gdk_gc_set_clip_origin (gc, old_clip_x, old_clip_y); \
       gdk_gc_set_ts_origin (gc, old_ts_x, old_ts_y);       \
     }

static GdkGC *
gdk_window_create_gc (GdkDrawable     *drawable,
                      GdkGCValues     *values,
                      GdkGCValuesMask  mask)
{
  g_return_val_if_fail (GDK_IS_WINDOW (drawable), NULL);
  
  if (GDK_WINDOW_DESTROYED (drawable))
    return NULL;

  return gdk_gc_new_with_values (((GdkWindowObject *) drawable)->impl,
                                 values, mask);
}

static void
gdk_window_draw_rectangle (GdkDrawable *drawable,
			   GdkGC       *gc,
			   gint         filled,
			   gint         x,
			   gint         y,
			   gint         width,
			   gint         height)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_rectangle (paint->pixmap, gc, filled,
			  x - x_offset, y - y_offset, width, height);
    }
  else
    gdk_draw_rectangle (private->impl, gc, filled,
                        x - x_offset, y - y_offset, width, height);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_arc (GdkDrawable *drawable,
		     GdkGC       *gc,
		     gint         filled,
		     gint         x,
		     gint         y,
		     gint         width,
		     gint         height,
		     gint         angle1,
		     gint         angle2)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_arc (paint->pixmap, gc, filled,
		    x - x_offset, y - y_offset,
		    width, height, angle1, angle2);
    }
  else
    gdk_draw_arc (private->impl, gc, filled,
                  x - x_offset, y - y_offset,
                  width, height, angle1, angle2);
  RESTORE_GC (gc);
}

static void
gdk_window_draw_polygon (GdkDrawable *drawable,
			 GdkGC       *gc,
			 gint         filled,
			 GdkPoint    *points,
			 gint         npoints)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  GdkPoint *new_points;
  
  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (x_offset != 0 || y_offset != 0)
    {
      int i;
      
      new_points = g_new (GdkPoint, npoints);
      for (i=0; i<npoints; i++)
	{
	  new_points[i].x = points[i].x - x_offset;
	  new_points[i].y = points[i].y - y_offset;
	}
    }
  else
    new_points = points;

  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_polygon (paint->pixmap, gc, filled, new_points, npoints);

    }
  else
    gdk_draw_polygon (private->impl, gc, filled, new_points, npoints);
  
  if (new_points != points)
    g_free (new_points);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_text (GdkDrawable *drawable,
		      GdkFont     *font,
		      GdkGC       *gc,
		      gint         x,
		      gint         y,
		      const gchar *text,
		      gint         text_length)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_text (paint->pixmap, font, gc, 
		     x - x_offset, y - y_offset, text, text_length);

    }
  else
    gdk_draw_text (private->impl, font, gc,
                   x - x_offset, y - y_offset, text, text_length);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_text_wc (GdkDrawable    *drawable,
			 GdkFont        *font,
			 GdkGC          *gc,
			 gint            x,
			 gint            y,
			 const GdkWChar *text,
			 gint            text_length)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_text_wc (paint->pixmap, font, gc, 
			x - x_offset, y - y_offset, text, text_length);
    }
  else
    gdk_draw_text_wc (private->impl, font, gc,
                      x - x_offset, y - y_offset, text, text_length);
  
  RESTORE_GC (gc);
}

static GdkDrawable*
gdk_window_get_composite_drawable (GdkDrawable *window,
                                   gint         x,
                                   gint         y,
                                   gint         width,
                                   gint         height,
                                   gint        *composite_x_offset,
                                   gint        *composite_y_offset)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  GdkWindowPaint *paint;
  GdkRegion *buffered_region;
  GSList *tmp_list;
  GdkPixmap *buffer;
  GdkPixmap *tmp_pixmap;
  GdkRectangle rect;
  GdkRegion *rect_region;
  GdkGC *tmp_gc;
  gint windowing_x_offset, windowing_y_offset;
  gint buffer_x_offset, buffer_y_offset;

  if (GDK_WINDOW_DESTROYED (window) || private->paint_stack == NULL)
    {
      /* No backing store */
      _gdk_windowing_window_get_offsets (window,
                                         composite_x_offset,
                                         composite_y_offset);
      
      return GDK_DRAWABLE (g_object_ref (G_OBJECT (window)));
    }
  
  buffered_region = NULL;
  buffer = NULL;

  /* All GtkWindowPaint structs have the same pixmap and offsets, just
   * get the first one. (should probably be cleaned up so that the
   * pixmap is stored in the window)
   */
  paint = private->paint_stack->data;
  buffer = paint->pixmap;
  buffer_x_offset = paint->x_offset;
  buffer_y_offset = paint->y_offset;
  
  tmp_list = private->paint_stack;
  while (tmp_list != NULL)
    {
      paint = tmp_list->data;
      
      if (buffered_region == NULL)
        buffered_region = gdk_region_copy (paint->region);
      else
        gdk_region_union (buffered_region, paint->region);

      tmp_list = g_slist_next (tmp_list);
    }

  /* See if the buffered part is overlapping the part we want
   * to get
   */
  rect.x = x;
  rect.y = y;
  rect.width = width;
  rect.height = height;

  rect_region = gdk_region_rectangle (&rect);
  
  gdk_region_intersect (buffered_region, rect_region);

  gdk_region_destroy (rect_region);

  if (gdk_region_empty (buffered_region))
    {
      gdk_region_destroy (buffered_region);

      _gdk_windowing_window_get_offsets (window,
                                         composite_x_offset,
                                         composite_y_offset);

      return GDK_DRAWABLE (g_object_ref (G_OBJECT (window)));
    }
  
  tmp_pixmap = gdk_pixmap_new (window,
                               width, height,
                               -1);

  tmp_gc = gdk_gc_new (tmp_pixmap);

  _gdk_windowing_window_get_offsets (window,
                                     &windowing_x_offset,
                                     &windowing_y_offset);
  
  /* Copy the current window contents */
  gdk_draw_drawable (tmp_pixmap,
                     tmp_gc,
                     private->impl,
                     x - windowing_x_offset,
                     y - windowing_y_offset,
                     0, 0,
                     width, height);

  /* Make buffered_region relative to the tmp_pixmap */
  gdk_region_offset (buffered_region,
                     - x,
                     - y);
  
  /* Set the clip mask to avoid drawing over non-buffered areas of
   * tmp_pixmap. 
   */
  
  gdk_gc_set_clip_region (tmp_gc, buffered_region);
  gdk_region_destroy (buffered_region);
  
  /* Draw backing pixmap onto the tmp_pixmap, offsetting
   * appropriately.
   */
  gdk_draw_drawable (tmp_pixmap,
                     tmp_gc,
                     buffer,
                     x - buffer_x_offset,
                     y - buffer_y_offset,
                     0, 0,
                     width, height);
  
  /* Set these to location of tmp_pixmap within the window */
  *composite_x_offset = x;
  *composite_y_offset = y;

  g_object_unref (G_OBJECT (tmp_gc));
  
  return tmp_pixmap;
}

static GdkRegion*
gdk_window_get_clip_region (GdkDrawable *drawable)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  GdkRegion *result;

  result = gdk_drawable_get_clip_region (private->impl);

  if (private->paint_stack)
    {
      GdkRegion *paint_region = gdk_region_new ();
      GSList *tmp_list = private->paint_stack;

      while (tmp_list)
	{
	  GdkWindowPaint *paint = tmp_list->data;
	  
	  gdk_region_union (paint_region, paint->region);

          tmp_list = tmp_list->next;
	}

      gdk_region_intersect (result, paint_region);
      gdk_region_destroy (paint_region);
    }

  return result;
}

static GdkRegion*
gdk_window_get_visible_region (GdkDrawable *drawable)
{
  GdkWindowObject *private = (GdkWindowObject*) drawable;
  
  return gdk_drawable_get_visible_region (private->impl);
}

static void
gdk_window_draw_drawable (GdkDrawable *drawable,
			  GdkGC       *gc,
			  GdkPixmap   *src,
			  gint         xsrc,
			  gint         ysrc,
			  gint         xdest,
			  gint         ydest,
			  gint         width,
			  gint         height)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  OFFSET_GC (gc);
  
  if (GDK_WINDOW_DESTROYED (drawable))
    return;

  /* If we have a backing pixmap draw to that */
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_drawable (paint->pixmap, gc,
                         src, xsrc, ysrc,
			 xdest - x_offset, ydest - y_offset, width, height);

    }
  else
    gdk_draw_drawable (private->impl, gc,
                       src, xsrc, ysrc,
                       xdest - x_offset, ydest - y_offset,
                       width, height);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_points (GdkDrawable *drawable,
			GdkGC       *gc,
			GdkPoint    *points,
			gint         npoints)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  GdkPoint *new_points;
  
  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (x_offset != 0 || y_offset != 0)
    {
      gint i;

      new_points = g_new (GdkPoint, npoints);
      for (i=0; i<npoints; i++)
	{
	  new_points[i].x = points[i].x - x_offset;
	  new_points[i].y = points[i].y - y_offset;
	}
    }
  else
    new_points = points;

  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_points (paint->pixmap, gc, new_points, npoints);
    }
  else
    gdk_draw_points (private->impl, gc, points, npoints);

  if (new_points != points)
    g_free (new_points);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_segments (GdkDrawable *drawable,
			  GdkGC       *gc,
			  GdkSegment  *segs,
			  gint         nsegs)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  GdkSegment *new_segs;

  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (x_offset != 0 || y_offset != 0)
    {
      gint i;

      new_segs = g_new (GdkSegment, nsegs);
      for (i=0; i<nsegs; i++)
	{
	  new_segs[i].x1 = segs[i].x1 - x_offset;
	  new_segs[i].y1 = segs[i].y1 - y_offset;
	  new_segs[i].x2 = segs[i].x2 - x_offset;
	  new_segs[i].y2 = segs[i].y2 - y_offset;
	}
    }
  else
    new_segs = segs;

  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_segments (paint->pixmap, gc, new_segs, nsegs);
    }
  else
    gdk_draw_segments (private->impl, gc, new_segs, nsegs);
  
  if (new_segs != segs)
    g_free (new_segs);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_lines (GdkDrawable *drawable,
		       GdkGC       *gc,
		       GdkPoint    *points,
		       gint         npoints)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;
  GdkPoint *new_points;

  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (x_offset != 0 || y_offset != 0)
    {
      gint i;

      new_points = g_new (GdkPoint, npoints);
      for (i=0; i<npoints; i++)
	{
	  new_points[i].x = points[i].x - x_offset;
	  new_points[i].y = points[i].y - y_offset;
	}
    }
  else
    new_points = points;

  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_lines (paint->pixmap, gc, new_points, npoints);
    }
  else
    gdk_draw_lines (private->impl, gc, new_points, npoints);

  if (new_points != points)
    g_free (new_points);

  RESTORE_GC (gc);
}

static void
gdk_window_draw_glyphs (GdkDrawable      *drawable,
			GdkGC            *gc,
			PangoFont        *font,
			gint              x,
			gint              y,
			PangoGlyphString *glyphs)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;

  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;

      gdk_draw_glyphs (paint->pixmap, gc, font, x - x_offset, y - y_offset, glyphs);
    }
  else
    gdk_draw_glyphs (private->impl, gc, font,
                     x - x_offset, y - y_offset, glyphs);

  RESTORE_GC (gc);
}

/* Fixme - this is just like gdk_window_paint_init_bg */
static void
gdk_window_clear_backing_rect (GdkWindow *window,
			       gint       x,
			       gint       y,
			       gint       width,
			       gint       height)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  GdkWindowPaint *paint = private->paint_stack->data;
  GdkGC *tmp_gc;

  if (GDK_WINDOW_DESTROYED (window))
    return;
  
  tmp_gc = gdk_window_get_bg_gc (window, paint);
  gdk_draw_rectangle (paint->pixmap, tmp_gc, TRUE,
		      x - paint->x_offset, y - paint->y_offset, width, height);
  gdk_gc_unref (tmp_gc);
}

void
gdk_window_clear (GdkWindow *window)
{
  gint width, height;
  
  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  gdk_drawable_get_size (GDK_DRAWABLE (window), &width, &height);
  
  gdk_window_clear_area (window, 0, 0,
                         width, height);
}

void
gdk_window_clear_area (GdkWindow *window,
		       gint       x,
		       gint       y,
		       gint       width,
		       gint       height)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));
  
  if (private->paint_stack)
    gdk_window_clear_backing_rect (window, x, y, width, height);
  else
    _gdk_windowing_window_clear_area (window, x, y, width, height);
}

void
gdk_window_clear_area_e (GdkWindow *window,
		         gint       x,
		         gint       y,
		         gint       width,
		         gint       height)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));
  
  if (private->paint_stack)
    gdk_window_clear_backing_rect (window, x, y, width, height);

  _gdk_windowing_window_clear_area_e (window, x, y, width, height);
}

static void
gdk_window_draw_image (GdkDrawable *drawable,
                       GdkGC       *gc,
                       GdkImage    *image,
                       gint         xsrc,
                       gint         ysrc,
                       gint         xdest,
                       gint         ydest,
                       gint         width,
                       gint         height)
{
  GdkWindowObject *private = (GdkWindowObject *)drawable;

  OFFSET_GC (gc);

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  if (private->paint_stack)
    {
      GdkWindowPaint *paint = private->paint_stack->data;
      gdk_draw_image (paint->pixmap, gc, image, xsrc, ysrc,
                      xdest - x_offset, ydest - y_offset,
                      width, height);

    }
  else
    gdk_draw_image (private->impl, gc, image, xsrc, ysrc,
                    xdest - x_offset, ydest - y_offset,
                    width, height);

  RESTORE_GC (gc);
}


static void
gdk_window_real_get_size (GdkDrawable *drawable,
                          gint *width,
                          gint *height)
{
  g_return_if_fail (GDK_IS_WINDOW (drawable));

  gdk_drawable_get_size (GDK_WINDOW_OBJECT (drawable)->impl,
                         width, height);
}

static GdkVisual*
gdk_window_real_get_visual (GdkDrawable *drawable)
{
  GdkColormap *colormap;

  g_return_val_if_fail (GDK_IS_WINDOW (drawable), NULL);

  colormap = gdk_drawable_get_colormap (drawable);
  return colormap ? gdk_colormap_get_visual (colormap) : NULL;
}

static gint
gdk_window_real_get_depth (GdkDrawable *drawable)
{
  gint depth;
  
  g_return_val_if_fail (GDK_IS_WINDOW (drawable), 0);

  depth = ((GdkWindowObject *)GDK_WINDOW (drawable))->depth;

  if (depth == 0)
    {
      g_print ("0 depth for type %s\n", g_type_name (G_OBJECT_TYPE (drawable)));
      G_BREAKPOINT ();
    }

  return depth;
}

static void
gdk_window_real_set_colormap (GdkDrawable *drawable,
                              GdkColormap *cmap)
{
  g_return_if_fail (GDK_IS_WINDOW (drawable));  

  if (GDK_WINDOW_DESTROYED (drawable))
    return;
  
  gdk_drawable_set_colormap (((GdkWindowObject*)drawable)->impl, cmap);
}

static GdkColormap*
gdk_window_real_get_colormap (GdkDrawable *drawable)
{
  g_return_val_if_fail (GDK_IS_WINDOW (drawable), NULL);

  if (GDK_WINDOW_DESTROYED (drawable))
    return NULL;
  
  return gdk_drawable_get_colormap (((GdkWindowObject*)drawable)->impl);
}
                      
static GdkImage*
gdk_window_get_image (GdkDrawable *drawable,
                      gint         x,
                      gint         y,
                      gint         width,
                      gint         height)
{
  gint x_offset, y_offset;
  
  g_return_val_if_fail (GDK_IS_WINDOW (drawable), NULL);
  
  if (GDK_WINDOW_DESTROYED (drawable))
    return NULL;

  /* If we're here, a composite image was not necessary, so
   * we can ignore the paint stack.
   */
  
  _gdk_windowing_window_get_offsets (drawable, &x_offset, &y_offset);
  
  return gdk_drawable_get_image (((GdkWindowObject*)drawable)->impl,
                                 x - x_offset,
                                 y - y_offset,
                                 width, height);
}

/* Code for dirty-region queueing
 */

static GSList *update_windows = NULL;
static guint update_idle = 0;
static gboolean debug_updates = FALSE;

static void
gdk_window_process_updates_internal (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  gboolean save_region = FALSE;

  /* If an update got queued during update processing, we can get a
   * window in the update queue that has an empty update_area.
   * just ignore it.
   */
  if (private->update_area)
    {
      GdkRegion *update_area = private->update_area;
      private->update_area = NULL;
      
      if (_gdk_event_func && gdk_window_is_viewable (window))
	{
	  GdkEvent event;
	  GdkRectangle window_rect;
	  GdkRegion *expose_region;
	  GdkRegion *window_region;
          gint width, height;

          if (debug_updates)
            {
              /* Make sure we see the red invalid area before redrawing. */
              gdk_flush ();
              g_usleep (70000);
            }
          
          gdk_drawable_get_size (GDK_DRAWABLE (private), &width, &height);
          
	  window_rect.x = 0;
	  window_rect.y = 0;
	  window_rect.width = width;
	  window_rect.height = height;

	  save_region = _gdk_windowing_window_queue_antiexpose (window, update_area);
      
	  event.expose.type = GDK_EXPOSE;
	  event.expose.window = gdk_window_ref (window);
	  event.expose.count = 0;

	  if (save_region)
	    expose_region = gdk_region_copy (update_area);
	  else
	    expose_region = update_area;
	  window_region = gdk_region_rectangle (&window_rect);
	  gdk_region_intersect (expose_region,
				window_region);
	  gdk_region_destroy (window_region);
	  
	  event.expose.region = expose_region;
	  gdk_region_get_clipbox (expose_region, &event.expose.area);
	  
	  if (!gdk_region_empty (expose_region))
	    {
	      (*_gdk_event_func) (&event, _gdk_event_data);
	    }

	  if (expose_region != update_area)
	    gdk_region_destroy (expose_region);
	  gdk_window_unref (window);
	}
      if (!save_region)
	gdk_region_destroy (update_area);
    }
}

/**
 * gdk_window_process_all_updates:
 *
 * Calls gdk_window_process_updates() for all windows (see #GdkWindow)
 * in the application.
 * 
 **/
void
gdk_window_process_all_updates (void)
{
  GSList *old_update_windows = update_windows;
  GSList *tmp_list = update_windows;

  if (update_idle)
    g_source_remove (update_idle);
  
  update_windows = NULL;
  update_idle = 0;

  while (tmp_list)
    {
      gdk_window_process_updates_internal (tmp_list->data);
      tmp_list = tmp_list->next;
    }

  g_slist_free (old_update_windows);

  gdk_flush();
}

static gboolean
gdk_window_update_idle (gpointer data)
{
  gdk_window_process_all_updates ();
  
  return FALSE;
}

/**
 * gdk_window_process_updates:
 * @window: a #GdkWindow
 * @update_children: whether to also process updates for child windows
 *
 * Sends one or more expose events to @window. The areas in each 
 * expose event will cover the entire update area for the window (see
 * gdk_window_invalidate_region() for details). Normally GDK calls
 * gdk_window_process_all_updates() on your behalf, so there's no
 * need to call this function unless you want to force expose events
 * to be delivered immediately and synchronously (vs. the usual
 * case, where GDK delivers them in an idle handler). Occasionally
 * this is useful to produce nicer scrolling behavior, for example.
 * 
 **/
void
gdk_window_process_updates (GdkWindow *window,
			    gboolean   update_children)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));
  
  if (private->update_area)
    {      
      gdk_window_process_updates_internal (window);
      update_windows = g_slist_remove (update_windows, window);
    }

  if (update_children)
    {
      GList *tmp_list = private->children;
      while (tmp_list)
	{
	  gdk_window_process_updates (tmp_list->data, TRUE);
	  tmp_list = tmp_list->next;
	}
    }
}

/**
 * gdk_window_invalidate_rect:
 * @window: a #GdkWindow
 * @rect: rectangle to invalidate
 * @invalidate_children: whether to also invalidate child windows
 *
 * A convenience wrapper around gdk_window_invalidate_region() which
 * invalidates a rectangular region. See
 * gdk_window_invalidate_region() for details.
 * 
 **/
void
gdk_window_invalidate_rect   (GdkWindow    *window,
			      GdkRectangle *rect,
			      gboolean      invalidate_children)
{
  GdkRectangle window_rect;
  GdkRegion *region;
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  if (GDK_WINDOW_DESTROYED (window))
    return;
  
  if (private->input_only || !GDK_WINDOW_IS_MAPPED (window))
    return;

  if (!rect)
    {
      window_rect.x = 0;
      window_rect.y = 0;
      gdk_drawable_get_size (GDK_DRAWABLE (window),
                             &window_rect.width,
                             &window_rect.height);
      rect = &window_rect;
    }

  region = gdk_region_rectangle (rect);
  gdk_window_invalidate_region (window, region, invalidate_children);
  gdk_region_destroy (region);
}

/**
 * gdk_window_invalidate_region:
 * @window: a #GdkWindow
 * @region: a #GdkRegion
 * @invalidate_children: %TRUE to also invalidate child windows 
 *
 * Adds @region to the update area for @window. The update area is the
 * region that needs to be redrawn, or "dirty region." The call
 * gdk_window_process_updates() sends one or more expose events to the
 * window, which together cover the entire update area. An
 * application would normally redraw the contents of @window in
 * response to those expose events.
 *
 * GDK will call gdk_window_process_all_updates() on your behalf
 * whenever your program returns to the main loop and becomes idle, so
 * normally there's no need to do that manually, you just need to
 * invalidate regions that you know should be redrawn.
 *
 * The @invalidate_children parameter controls whether the region of
 * each child window that intersects @region will also be invalidated.
 * If %FALSE, then the update area for child windows will remain
 * unaffected.
 *
 **/
void
gdk_window_invalidate_region (GdkWindow *window,
			      GdkRegion *region,
			      gboolean   invalidate_children)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  GdkRegion *visible_region;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  if (GDK_WINDOW_DESTROYED (window))
    return;
  
  if (private->input_only || !GDK_WINDOW_IS_MAPPED (window))
    return;

  visible_region = gdk_drawable_get_visible_region (window);
  gdk_region_intersect (visible_region, region);

  if (!gdk_region_empty (visible_region))
    {
      if (debug_updates)
        {
          /* Draw ugly color all over the newly-invalid region */
          GdkRectangle ugly_rect;
          GdkGC *ugly_gc;
          GdkColor ugly_color = { 0, 60000, 10000, 10000 };
          
          ugly_gc = gdk_gc_new (window);

          gdk_gc_set_rgb_fg_color (ugly_gc, &ugly_color);
          
	  gdk_region_get_clipbox (visible_region, &ugly_rect);

          gdk_draw_rectangle (window,
                              ugly_gc,
                              TRUE,
                              ugly_rect.x, ugly_rect.y,
                              ugly_rect.width, ugly_rect.height);
          
          g_object_unref (G_OBJECT (ugly_gc));
        }
      
      if (private->update_area)
	{
	  gdk_region_union (private->update_area, visible_region);
	}
      else
	{
	  update_windows = g_slist_prepend (update_windows, window);
	  private->update_area = gdk_region_copy (visible_region);
	  
	  if (!private->update_freeze_count && !update_idle)
	    update_idle = g_idle_add_full (GDK_PRIORITY_REDRAW,
					   gdk_window_update_idle, NULL, NULL);
	}
      
      if (invalidate_children)
	{
	  GList *tmp_list;
	  
	  tmp_list = private->children;
	  while (tmp_list)
	    {
	      GdkWindowObject *child = tmp_list->data;
	      tmp_list = tmp_list->next;
	      
	      if (!child->input_only)
		{
		  GdkRegion *child_region;
		  gint x, y;

		  gdk_window_get_position ((GdkWindow *)child, &x, &y);

		  /* This copy could be saved with a little more complexity */
		  child_region = gdk_region_copy (visible_region);
		  gdk_region_offset (child_region, -x, -y);
		  
		  gdk_window_invalidate_region ((GdkWindow *)child, child_region, TRUE);
		  
		  gdk_region_destroy (child_region);
		}
	    }
	}
    }
  
  gdk_region_destroy (visible_region);
}

/**
 * gdk_window_get_update_area:
 * @window: a #GdkWindow
 * 
 * Transfers ownership of the update area from @window to the caller
 * of the function. That is, after calling this function, @window will
 * no longer have an invalid/dirty region; the update area is removed
 * from @window and handed to you. If a window has no update area,
 * gdk_window_get_update_area() returns %NULL. You are responsible for
 * calling gdk_region_destroy() on the returned region if it's non-%NULL.
 * 
 * Return value: the update area for @window
 **/
GdkRegion *
gdk_window_get_update_area (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;
  GdkRegion *tmp_region;

  g_return_val_if_fail (window != NULL, NULL);
  g_return_val_if_fail (GDK_IS_WINDOW (window), NULL);

  if (private->update_area)
    {
      tmp_region = private->update_area;
      private->update_area = NULL;

      update_windows = g_slist_remove (update_windows, window);
      
      return tmp_region;
    }
  else
    return NULL;
}

/**
 * _gdk_window_clear_update_area:
 * @window: a #GdkWindow.
 * 
 * Internal function to clear the update area for a window. This
 * is called when the window is hidden or destroyed.
 **/
void
_gdk_window_clear_update_area (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  if (private->update_area)
    {
      update_windows = g_slist_remove (update_windows, window);
      
      gdk_region_destroy (private->update_area);
      private->update_area = NULL;
    }
}

void
gdk_window_freeze_updates (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));

  private->update_freeze_count++;
}

void
gdk_window_thaw_updates (GdkWindow *window)
{
  GdkWindowObject *private = (GdkWindowObject *)window;

  g_return_if_fail (window != NULL);
  g_return_if_fail (GDK_IS_WINDOW (window));
  g_return_if_fail (private->update_freeze_count > 0);

  private->update_freeze_count--;
  if (!private->update_freeze_count && private->update_area && !update_idle)
    update_idle = g_idle_add_full (GDK_PRIORITY_REDRAW,
				   gdk_window_update_idle, NULL, NULL);
}

/**
 * gdk_window_set_debug_updates:
 * @setting: %TRUE to turn on update debugging
 *
 * With update debugging enabled, calls to
 * gdk_window_invalidate_region() clear the invalidated region of the
 * screen to a noticeable color, and GDK pauses for a short time
 * before sending exposes to windows during
 * gdk_window_process_updates().  The net effect is that you can see
 * the invalid region for each window and watch redraws as they
 * occur. This allows you to diagnose inefficiencies in your application.
 *
 * In essence, because the GDK rendering model prevents all flicker,
 * if you are redrawing the same region 400 times you may never
 * notice, aside from noticing a speed problem. Enabling update
 * debugging causes GTK to flicker slowly and noticeably, so you can
 * see exactly what's being redrawn when, in what order.
 *
 * The --gtk-debug=updates command line option passed to GTK+ programs
 * enables this debug option at application startup time. That's
 * usually more useful than calling gdk_window_set_debug_updates()
 * yourself, though you might want to use this function to enable
 * updates sometime after application startup time.
 * 
 **/
void
gdk_window_set_debug_updates (gboolean setting)
{
  debug_updates = setting;
}

/**
 * gdk_window_constrain_size:
 * @geometry: a #GdkGeometry structure
 * @flags: a mask indicating what portions of @geometry are set
 * @width: desired width of window
 * @height: desired height of the window
 * @new_width: location to store resulting width
 * @new_height: location to store resulting height
 * 
 * Constrains a desired width and height according to a 
 * set of geometry hints (such as minimum and maximum size).
 */
void
gdk_window_constrain_size (GdkGeometry *geometry,
			   guint        flags,
			   gint         width,
			   gint         height,
			   gint        *new_width,
			   gint        *new_height)
{
  /* This routine is partially borrowed from fvwm.
   *
   * Copyright 1993, Robert Nation
   *     You may use this code for any purpose, as long as the original
   *     copyright remains in the source code and all documentation
   *
   * which in turn borrows parts of the algorithm from uwm
   */
  gint min_width = 0;
  gint min_height = 0;
  gint base_width = 0;
  gint base_height = 0;
  gint xinc = 1;
  gint yinc = 1;
  gint max_width = G_MAXINT;
  gint max_height = G_MAXINT;
  
#define FLOOR(value, base)	( ((gint) ((value) / (base))) * (base) )

  if ((flags & GDK_HINT_BASE_SIZE) && (flags & GDK_HINT_MIN_SIZE))
    {
      base_width = geometry->base_width;
      base_height = geometry->base_height;
      min_width = geometry->min_width;
      min_height = geometry->min_height;
    }
  else if (flags & GDK_HINT_BASE_SIZE)
    {
      base_width = geometry->base_width;
      base_height = geometry->base_height;
      min_width = geometry->base_width;
      min_height = geometry->base_height;
    }
  else if (flags & GDK_HINT_MIN_SIZE)
    {
      base_width = geometry->min_width;
      base_height = geometry->min_height;
      min_width = geometry->min_width;
      min_height = geometry->min_height;
    }

  if (flags & GDK_HINT_MAX_SIZE)
    {
      max_width = geometry->max_width ;
      max_height = geometry->max_height;
    }

  if (flags & GDK_HINT_RESIZE_INC)
    {
      xinc = MAX (xinc, geometry->width_inc);
      yinc = MAX (yinc, geometry->height_inc);
    }
  
  /* clamp width and height to min and max values
   */
  width = CLAMP (width, min_width, max_width);
  height = CLAMP (height, min_height, max_height);
  
  /* shrink to base + N * inc
   */
  width = base_width + FLOOR (width - base_width, xinc);
  height = base_height + FLOOR (height - base_height, yinc);

  /* constrain aspect ratio, according to:
   *
   *                width     
   * min_aspect <= -------- <= max_aspect
   *                height    
   */
  
  if (flags & GDK_HINT_ASPECT &&
      geometry->min_aspect > 0 &&
      geometry->max_aspect > 0)
    {
      gint delta;

      if (geometry->min_aspect * height > width)
	{
	  delta = FLOOR (height - width * geometry->min_aspect, yinc);
	  if (height - delta >= min_height)
	    height -= delta;
	  else
	    { 
	      delta = FLOOR (height * geometry->min_aspect - width, xinc);
	      if (width + delta <= max_width) 
		width += delta;
	    }
	}
      
      if (geometry->max_aspect * height < width)
	{
	  delta = FLOOR (width - height * geometry->max_aspect, xinc);
	  if (width - delta >= min_width) 
	    width -= delta;
	  else
	    {
	      delta = FLOOR (width / geometry->max_aspect - height, yinc);
	      if (height + delta <= max_height)
		height += delta;
	    }
	}
    }

#undef FLOOR
  
  *new_width = width;
  *new_height = height;
}

/**
 * gdk_set_pointer_hooks:
 * @new_hooks: a table of pointer to functions for getting
 *   quantities related to the current pointer position,
 *   or %NULL to restore the default table.
 * 
 * This function allows for hooking into the operation
 * of getting the current location of the pointer. This
 * is only useful for such low-level tools as an
 * event recorder. Applications should never have any
 * reason to use this facility
 * 
 * Return value: the previous pointer hook table
 **/
GdkPointerHooks *
gdk_set_pointer_hooks (const GdkPointerHooks *new_hooks)
{
  const GdkPointerHooks *result = current_pointer_hooks;

  if (new_hooks)
    current_pointer_hooks = new_hooks;
  else
    current_pointer_hooks = &default_pointer_hooks;

  return (GdkPointerHooks *)result;
}

GdkWindow*
gdk_window_get_pointer (GdkWindow	  *window,
			gint		  *x,
			gint		  *y,
			GdkModifierType *mask)
{
  g_return_val_if_fail (window == NULL || GDK_IS_WINDOW (window), NULL);
  
  return current_pointer_hooks->get_pointer (window, x, y, mask); 
}

GdkWindow*
gdk_window_at_pointer (gint *win_x,
		       gint *win_y)
{
  return current_pointer_hooks->window_at_pointer (win_x, win_y);
}

GdkWindow *
gdk_get_default_root_window (void)
{
  return _gdk_parent_root;
}