Initial GTK4 / 4.0 port.wip/gtk4

This is quite rough, but it compiles. bg-crossfade is dropped.

21 files changed, 166 insertions, 785 deletions

diff --git a/docs/reference/gnome-desktop3/gnome-desktop3-docs.sgml b/docs/reference/gnome-desktop4/gnome-desktop4-docs.sgml
index e6e111e4..e6e111e4 100644
--- a/docs/reference/gnome-desktop3/gnome-desktop3-docs.sgml
+++ b/docs/reference/gnome-desktop4/gnome-desktop4-docs.sgml
diff --git a/docs/reference/gnome-desktop3/gnome-desktop3-sections.txt b/docs/reference/gnome-desktop4/gnome-desktop4-sections.txt
index 4f189fcd..af423bcd 100644
--- a/docs/reference/gnome-desktop3/gnome-desktop3-sections.txt
+++ b/docs/reference/gnome-desktop4/gnome-desktop4-sections.txt
@@ -18,7 +18,6 @@ gnome_bg_has_multiple_sizes
 gnome_bg_changes_with_time
 gnome_bg_create_frame_thumbnail
 gnome_bg_set_surface_as_root
-gnome_bg_set_surface_as_root_with_crossfade
 gnome_bg_get_surface_from_root
 GnomeBG
 GnomeBGClass
@@ -61,28 +60,6 @@ GNOME_DESKTOP_IS_THUMBNAIL_FACTORY_CLASS
 </SECTION>
 
 <SECTION>
-<FILE>gnome-bg-crossfade</FILE>
-<TITLE>GnomeBGCrossfade</TITLE>
-GnomeBGCrossfade
-GnomeBGCrossfadeClass
-gnome_bg_crossfade_new
-gnome_bg_crossfade_set_start_surface
-gnome_bg_crossfade_set_end_surface
-gnome_bg_crossfade_start
-gnome_bg_crossfade_is_started
-gnome_bg_crossfade_stop
-GnomeBGCrossfadePrivate
-<SUBSECTION Standard>
-GNOME_BG_CROSSFADE
-GNOME_IS_BG_CROSSFADE
-GNOME_TYPE_BG_CROSSFADE
-gnome_bg_crossfade_get_type
-GNOME_BG_CROSSFADE_CLASS
-GNOME_IS_BG_CROSSFADE_CLASS
-GNOME_BG_CROSSFADE_GET_CLASS
-</SECTION>
-
-<SECTION>
 <FILE>gnome-bg-slide-show</FILE>
 <TITLE>GnomeBGSlideShow</TITLE>
 GnomeBGSlideShow
diff --git a/docs/reference/gnome-desktop3/gnome-desktop3.types b/docs/reference/gnome-desktop4/gnome-desktop4.types
index dad5c940..056b1a3f 100644
--- a/docs/reference/gnome-desktop3/gnome-desktop3.types
+++ b/docs/reference/gnome-desktop4/gnome-desktop4.types
@@ -1,4 +1,3 @@
-gnome_bg_crossfade_get_type
 gnome_bg_get_type
 gnome_desktop_thumbnail_factory_get_type
 gnome_idle_monitor_get_type
diff --git a/docs/reference/gnome-desktop3/meson.build b/docs/reference/gnome-desktop4/meson.build
index cd89ae7c..16618660 100644
--- a/docs/reference/gnome-desktop3/meson.build
+++ b/docs/reference/gnome-desktop4/meson.build
@@ -6,8 +6,8 @@ ignored_headers = [
   'meta-xrandr-shared.h'
 ]
 
-gnome.gtkdoc('gnome-desktop3',
-  main_sgml: 'gnome-desktop3-docs.sgml',
+gnome.gtkdoc('gnome-desktop4',
+  main_sgml: 'gnome-desktop4-docs.sgml',
   ignore_headers: ignored_headers,
   scan_args: '--deprecated-guards="GNOME_DISABLE_DEPRECATED"',
   mkdb_args: ['--sgml-mode', '--output-format=xml'],
diff --git a/libgnome-desktop/gnome-bg-crossfade.c b/libgnome-desktop/gnome-bg-crossfade.c
deleted file mode 100644
index f254b313..00000000
--- a/libgnome-desktop/gnome-bg-crossfade.c
+++ /dev/null
@@ -1,543 +0,0 @@
-/* gnome-bg-crossfade.h - fade window background between two surfaces
- *
- * Copyright (C) 2008 Red Hat, Inc.
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Library General Public License
- * as published by the Free Software Foundation; either version 2 of
- * the License, or (at your option) any later version.
- *
- * This program 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
- * Library General Public License for more details.
- *
- * You should have received a copy of the GNU Library General Public
- * License along with this program; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
- * 02110-1301, USA.
- *
- * Author: Ray Strode <rstrode@redhat.com>
-*/
-
-#include <string.h>
-#include <math.h>
-#include <stdarg.h>
-
-#include <gio/gio.h>
-
-#include <gdk/gdk.h>
-#include <gtk/gtk.h>
-
-#include <cairo.h>
-
-#define GNOME_DESKTOP_USE_UNSTABLE_API
-#include "gnome-bg.h"
-#include "gnome-bg-crossfade.h"
-
-struct _GnomeBGCrossfadePrivate
-{
-	GdkWindow       *window;
-	int              width;
-	int              height;
-	cairo_surface_t *fading_surface;
-	cairo_surface_t *end_surface;
-	gdouble          start_time;
-	gdouble          total_duration;
-	guint            timeout_id;
-	guint            is_first_frame : 1;
-};
-
-enum {
-	PROP_0,
-	PROP_WIDTH,
-	PROP_HEIGHT,
-};
-
-enum {
-	FINISHED,
-	NUMBER_OF_SIGNALS
-};
-
-static guint signals[NUMBER_OF_SIGNALS] = { 0 };
-
-G_DEFINE_TYPE_WITH_PRIVATE (GnomeBGCrossfade, gnome_bg_crossfade, G_TYPE_OBJECT)
-
-static void
-gnome_bg_crossfade_set_property (GObject      *object,
-				 guint         property_id,
-				 const GValue *value,
-				 GParamSpec   *pspec)
-{
-	GnomeBGCrossfade *fade;
-
-	g_assert (GNOME_IS_BG_CROSSFADE (object));
-
-	fade = GNOME_BG_CROSSFADE (object);
-
-	switch (property_id)
-	{
-	case PROP_WIDTH:
-		fade->priv->width = g_value_get_int (value);
-		break;
-	case PROP_HEIGHT:
-		fade->priv->height = g_value_get_int (value);
-		break;
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-		break;
-	}
-}
-
-static void
-gnome_bg_crossfade_get_property (GObject    *object,
-			     guint       property_id,
-			     GValue     *value,
-			     GParamSpec *pspec)
-{
-	GnomeBGCrossfade *fade;
-
-	g_assert (GNOME_IS_BG_CROSSFADE (object));
-
-	fade = GNOME_BG_CROSSFADE (object);
-
-	switch (property_id)
-	{
-	case PROP_WIDTH:
-		g_value_set_int (value, fade->priv->width);
-		break;
-	case PROP_HEIGHT:
-		g_value_set_int (value, fade->priv->height);
-		break;
-
-	default:
-		G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
-		break;
-	}
-}
-
-static void
-gnome_bg_crossfade_finalize (GObject *object)
-{
-	GnomeBGCrossfade *fade;
-
-	fade = GNOME_BG_CROSSFADE (object);
-
-	gnome_bg_crossfade_stop (fade);
-
-	if (fade->priv->fading_surface != NULL) {
-		cairo_surface_destroy (fade->priv->fading_surface);
-		fade->priv->fading_surface = NULL;
-	}
-
-	if (fade->priv->end_surface != NULL) {
-		g_object_unref (fade->priv->end_surface);
-		fade->priv->end_surface = NULL;
-	}
-}
-
-static void
-gnome_bg_crossfade_class_init (GnomeBGCrossfadeClass *fade_class)
-{
-	GObjectClass *gobject_class;
-
-	gobject_class = G_OBJECT_CLASS (fade_class);
-
-	gobject_class->get_property = gnome_bg_crossfade_get_property;
-	gobject_class->set_property = gnome_bg_crossfade_set_property;
-	gobject_class->finalize = gnome_bg_crossfade_finalize;
-
-	/**
-	 * GnomeBGCrossfade:width:
-	 *
-	 * When a crossfade is running, this is width of the fading
-	 * surface.
-	 */
-	g_object_class_install_property (gobject_class,
-					 PROP_WIDTH,
-					 g_param_spec_int ("width",
-						           "Window Width",
-							    "Width of window to fade",
-							    0, G_MAXINT, 0,
-							    G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
-
-	/**
-	 * GnomeBGCrossfade:height:
-	 *
-	 * When a crossfade is running, this is height of the fading
-	 * surface.
-	 */
-	g_object_class_install_property (gobject_class,
-					 PROP_HEIGHT,
-					 g_param_spec_int ("height", "Window Height",
-						           "Height of window to fade on",
-							   0, G_MAXINT, 0,
-							   G_PARAM_CONSTRUCT_ONLY | G_PARAM_READWRITE));
-
-	/**
-	 * GnomeBGCrossfade::finished:
-	 * @fade: the #GnomeBGCrossfade that received the signal
-	 * @window: the #GdkWindow the crossfade happend on.
-	 *
-	 * When a crossfade finishes, @window will have a copy
-	 * of the end surface as its background, and this signal will
-	 * get emitted.
-	 */
-	signals[FINISHED] = g_signal_new ("finished",
-					  G_OBJECT_CLASS_TYPE (gobject_class),
-					  G_SIGNAL_RUN_LAST, 0, NULL, NULL,
-					  g_cclosure_marshal_VOID__OBJECT,
-					  G_TYPE_NONE, 1, G_TYPE_OBJECT);
-}
-
-static void
-gnome_bg_crossfade_init (GnomeBGCrossfade *fade)
-{
-	fade->priv = gnome_bg_crossfade_get_instance_private (fade);
-
-	fade->priv->fading_surface = NULL;
-	fade->priv->end_surface = NULL;
-	fade->priv->timeout_id = 0;
-}
-
-/**
- * gnome_bg_crossfade_new:
- * @width: The width of the crossfading window
- * @height: The height of the crossfading window
- *
- * Creates a new object to manage crossfading a
- * window background between two #cairo_surface_ts.
- *
- * Return value: the new #GnomeBGCrossfade
- **/
-GnomeBGCrossfade *
-gnome_bg_crossfade_new (int width,
-			int height)
-{
-	GObject *object;
-
-	object = g_object_new (GNOME_TYPE_BG_CROSSFADE,
-			       "width", width,
-			       "height", height, NULL);
-
-	return (GnomeBGCrossfade *) object;
-}
-
-static cairo_surface_t *
-tile_surface (cairo_surface_t *surface,
-	      int              width,
-	      int              height)
-{
-	cairo_surface_t *copy;
-	cairo_t *cr;
-
-        if (surface == NULL) {
-                copy = gdk_window_create_similar_surface (gdk_get_default_root_window (),
-                                                          CAIRO_CONTENT_COLOR,
-                                                          width, height);
-        } else {
-                copy = cairo_surface_create_similar (surface,
-                                                     cairo_surface_get_content (surface),
-                                                     width, height);
-        }
-
-	cr = cairo_create (copy);
-
-	if (surface != NULL) {
-		cairo_pattern_t *pattern;
-		cairo_set_source_surface (cr, surface, 0.0, 0.0);
-		pattern = cairo_get_source (cr);
-		cairo_pattern_set_extend (pattern, CAIRO_EXTEND_REPEAT);
-	} else {
-		GtkStyle *style;
-		style = gtk_widget_get_default_style ();
-		gdk_cairo_set_source_color (cr, &style->bg[GTK_STATE_NORMAL]);
-	}
-
-	cairo_paint (cr);
-
-	if (cairo_status (cr) != CAIRO_STATUS_SUCCESS) {
-		cairo_surface_destroy (copy);
-		copy = NULL;
-	}
-	cairo_destroy (cr);
-
-	return copy;
-}
-
-/**
- * gnome_bg_crossfade_set_start_surface:
- * @fade: a #GnomeBGCrossfade
- * @surface: The cairo surface to fade from
- *
- * Before initiating a crossfade with gnome_bg_crossfade_start()
- * a start and end surface have to be set.  This function sets
- * the surface shown at the beginning of the crossfade effect.
- *
- * Return value: %TRUE if successful, or %FALSE if the surface
- * could not be copied.
- **/
-gboolean
-gnome_bg_crossfade_set_start_surface (GnomeBGCrossfade *fade,
-				      cairo_surface_t  *surface)
-{
-	g_return_val_if_fail (GNOME_IS_BG_CROSSFADE (fade), FALSE);
-
-	if (fade->priv->fading_surface != NULL) {
-		cairo_surface_destroy (fade->priv->fading_surface);
-		fade->priv->fading_surface = NULL;
-	}
-
-	fade->priv->fading_surface = tile_surface (surface,
-						   fade->priv->width,
-						   fade->priv->height);
-
-	return fade->priv->fading_surface != NULL;
-}
-
-static gdouble
-get_current_time (void)
-{
-	const double microseconds_per_second = (double) G_USEC_PER_SEC;
-	double timestamp;
-	GTimeVal now;
-
-	g_get_current_time (&now);
-
-	timestamp = ((microseconds_per_second * now.tv_sec) + now.tv_usec) /
-	            microseconds_per_second;
-
-	return timestamp;
-}
-
-/**
- * gnome_bg_crossfade_set_end_surface:
- * @fade: a #GnomeBGCrossfade
- * @surface: The cairo surface to fade to
- *
- * Before initiating a crossfade with gnome_bg_crossfade_start()
- * a start and end surface have to be set.  This function sets
- * the surface shown at the end of the crossfade effect.
- *
- * Return value: %TRUE if successful, or %FALSE if the surface
- * could not be copied.
- **/
-gboolean
-gnome_bg_crossfade_set_end_surface (GnomeBGCrossfade *fade,
-				    cairo_surface_t  *surface)
-{
-	g_return_val_if_fail (GNOME_IS_BG_CROSSFADE (fade), FALSE);
-
-	if (fade->priv->end_surface != NULL) {
-		cairo_surface_destroy (fade->priv->end_surface);
-		fade->priv->end_surface = NULL;
-	}
-
-	fade->priv->end_surface = tile_surface (surface,
-					        fade->priv->width,
-					        fade->priv->height);
-
-	/* Reset timer in case we're called while animating
-	 */
-	fade->priv->start_time = get_current_time ();
-	return fade->priv->end_surface != NULL;
-}
-
-static gboolean
-animations_are_disabled (GnomeBGCrossfade *fade)
-{
-	GtkSettings *settings;
-	GdkScreen *screen;
-	gboolean are_enabled;
-
-	g_assert (fade->priv->window != NULL);
-
-	screen = gdk_window_get_screen (fade->priv->window);
-
-	settings = gtk_settings_get_for_screen (screen);
-
-	g_object_get (settings, "gtk-enable-animations", &are_enabled, NULL);
-
-	return !are_enabled;
-}
-
-static void
-draw_background (GnomeBGCrossfade *fade)
-{
-	if (gdk_window_get_window_type (fade->priv->window) == GDK_WINDOW_ROOT) {
-		g_warning ("Crossfade is not supported on ROOT window!");
-	} else {
-		gdk_window_invalidate_rect (fade->priv->window, NULL, FALSE);
-		gdk_window_process_updates (fade->priv->window, FALSE);
-	}
-}
-
-static gboolean
-on_tick (GnomeBGCrossfade *fade)
-{
-	gdouble now, percent_done;
-	cairo_t *cr;
-	cairo_status_t status;
-
-	g_return_val_if_fail (GNOME_IS_BG_CROSSFADE (fade), FALSE);
-
-	now = get_current_time ();
-
-	percent_done = (now - fade->priv->start_time) / fade->priv->total_duration;
-	percent_done = CLAMP (percent_done, 0.0, 1.0);
-
-	/* If it's taking a long time to get to the first frame,
-	 * then lengthen the duration, so the user will get to see
-	 * the effect.
-	 */
-	if (fade->priv->is_first_frame && percent_done > .33) {
-		fade->priv->is_first_frame = FALSE;
-		fade->priv->total_duration *= 1.5;
-		return on_tick (fade);
-	}
-
-	if (fade->priv->fading_surface == NULL) {
-		return FALSE;
-	}
-
-	if (animations_are_disabled (fade)) {
-		return FALSE;
-	}
-
-	/* We accumulate the results in place for performance reasons.
-	 *
-	 * This means 1) The fade is exponential, not linear (looks good!)
-	 * 2) The rate of fade is not independent of frame rate. Slower machines
-	 * will get a slower fade (but never longer than .75 seconds), and
-	 * even the fastest machines will get *some* fade because the framerate
-	 * is capped.
-	 */
-	cr = cairo_create (fade->priv->fading_surface);
-
-	cairo_set_source_surface (cr, fade->priv->end_surface,
-				  0.0, 0.0);
-	cairo_paint_with_alpha (cr, percent_done);
-
-	status = cairo_status (cr);
-	cairo_destroy (cr);
-
-	if (status == CAIRO_STATUS_SUCCESS) {
-		draw_background (fade);
-	}
-	return percent_done <= .99;
-}
-
-static void
-on_finished (GnomeBGCrossfade *fade)
-{
-        cairo_pattern_t *pattern;
-
-	if (fade->priv->timeout_id == 0)
-		return;
-
-	g_assert (fade->priv->end_surface != NULL);
-
-        pattern = cairo_pattern_create_for_surface (fade->priv->end_surface);
-	gdk_window_set_background_pattern (fade->priv->window, pattern);
-        cairo_pattern_destroy (pattern);
-
-	draw_background (fade);
-
-	cairo_surface_destroy (fade->priv->end_surface);
-	fade->priv->end_surface = NULL;
-
-	g_assert (fade->priv->fading_surface != NULL);
-
-	cairo_surface_destroy (fade->priv->fading_surface);
-	fade->priv->fading_surface = NULL;
-
-	fade->priv->timeout_id = 0;
-	g_signal_emit (fade, signals[FINISHED], 0, fade->priv->window);
-}
-
-/**
- * gnome_bg_crossfade_start:
- * @fade: a #GnomeBGCrossfade
- * @window: The #GdkWindow to draw crossfade on
- *
- * This function initiates a quick crossfade between two surfaces on
- * the background of @window.  Before initiating the crossfade both
- * gnome_bg_crossfade_start() and gnome_bg_crossfade_end() need to
- * be called. If animations are disabled, the crossfade is skipped,
- * and the window background is set immediately to the end surface.
- **/
-void
-gnome_bg_crossfade_start (GnomeBGCrossfade *fade,
-			  GdkWindow        *window)
-{
-	GSource *source;
-	GMainContext *context;
-        cairo_pattern_t *pattern;
-
-	g_return_if_fail (GNOME_IS_BG_CROSSFADE (fade));
-	g_return_if_fail (window != NULL);
-	g_return_if_fail (fade->priv->fading_surface != NULL);
-	g_return_if_fail (fade->priv->end_surface != NULL);
-	g_return_if_fail (!gnome_bg_crossfade_is_started (fade));
-	g_return_if_fail (gdk_window_get_window_type (window) != GDK_WINDOW_FOREIGN);
-
-	source = g_timeout_source_new (1000 / 60.0);
-	g_source_set_callback (source,
-			       (GSourceFunc) on_tick,
-			       fade,
-			       (GDestroyNotify) on_finished);
-	context = g_main_context_default ();
-	fade->priv->timeout_id = g_source_attach (source, context);
-	g_source_unref (source);
-
-	fade->priv->window = window;
-        pattern = cairo_pattern_create_for_surface (fade->priv->fading_surface);
-	gdk_window_set_background_pattern (fade->priv->window, pattern);
-        cairo_pattern_destroy (pattern);
-
-	draw_background (fade);
-
-	fade->priv->is_first_frame = TRUE;
-	fade->priv->total_duration = .75;
-	fade->priv->start_time = get_current_time ();
-}
-
-
-/**
- * gnome_bg_crossfade_is_started:
- * @fade: a #GnomeBGCrossfade
- *
- * This function reveals whether or not @fade is currently
- * running on a window.  See gnome_bg_crossfade_start() for
- * information on how to initiate a crossfade.
- *
- * Return value: %TRUE if fading, or %FALSE if not fading
- **/
-gboolean
-gnome_bg_crossfade_is_started (GnomeBGCrossfade *fade)
-{
-	g_return_val_if_fail (GNOME_IS_BG_CROSSFADE (fade), FALSE);
-
-	return fade->priv->timeout_id != 0;
-}
-
-/**
- * gnome_bg_crossfade_stop:
- * @fade: a #GnomeBGCrossfade
- *
- * This function stops any in progress crossfades that may be
- * happening.  It's harmless to call this function if @fade is
- * already stopped.
- **/
-void
-gnome_bg_crossfade_stop (GnomeBGCrossfade *fade)
-{
-	g_return_if_fail (GNOME_IS_BG_CROSSFADE (fade));
-
-	if (!gnome_bg_crossfade_is_started (fade))
-		return;
-
-	g_assert (fade->priv->timeout_id != 0);
-	g_source_remove (fade->priv->timeout_id);
-	fade->priv->timeout_id = 0;
-}
diff --git a/libgnome-desktop/gnome-bg-crossfade.h b/libgnome-desktop/gnome-bg-crossfade.h
deleted file mode 100644
index 119047da..00000000
--- a/libgnome-desktop/gnome-bg-crossfade.h
+++ /dev/null
@@ -1,76 +0,0 @@
-/* gnome-bg-crossfade.h - fade window background between two surfaces
-
-   Copyright 2008, Red Hat, Inc.
-
-   This file is part of the Gnome Library.
-
-   The Gnome Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Library General Public License as
-   published by the Free Software Foundation; either version 2 of the
-   License, or (at your option) any later version.
-
-   The Gnome 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
-   Library General Public License for more details.
-
-   You should have received a copy of the GNU Library General Public
-   License along with the Gnome Library; see the file COPYING.LIB.  If not,
-   write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
-   Boston, MA 02110-1301, USA.
-
-   Author: Ray Strode <rstrode@redhat.com>
-*/
-
-#ifndef __GNOME_BG_CROSSFADE_H__
-#define __GNOME_BG_CROSSFADE_H__
-
-#ifndef GNOME_DESKTOP_USE_UNSTABLE_API
-#error    GnomeBGCrossfade is unstable API. You must define GNOME_DESKTOP_USE_UNSTABLE_API before including gnome-bg-crossfade.h
-#endif
-
-#include <gdk/gdk.h>
-
-G_BEGIN_DECLS
-
-#define GNOME_TYPE_BG_CROSSFADE            (gnome_bg_crossfade_get_type ())
-#define GNOME_BG_CROSSFADE(obj)            (G_TYPE_CHECK_INSTANCE_CAST ((obj), GNOME_TYPE_BG_CROSSFADE, GnomeBGCrossfade))
-#define GNOME_BG_CROSSFADE_CLASS(klass)    (G_TYPE_CHECK_CLASS_CAST ((klass),  GNOME_TYPE_BG_CROSSFADE, GnomeBGCrossfadeClass))
-#define GNOME_IS_BG_CROSSFADE(obj)         (G_TYPE_CHECK_INSTANCE_TYPE ((obj), GNOME_TYPE_BG_CROSSFADE))
-#define GNOME_IS_BG_CROSSFADE_CLASS(klass) (G_TYPE_CHECK_CLASS_TYPE ((klass),  GNOME_TYPE_BG_CROSSFADE))
-#define GNOME_BG_CROSSFADE_GET_CLASS(obj)  (G_TYPE_INSTANCE_GET_CLASS ((obj),  GNOME_TYPE_BG_CROSSFADE, GnomeBGCrossfadeClass))
-
-typedef struct _GnomeBGCrossfadePrivate GnomeBGCrossfadePrivate;
-typedef struct _GnomeBGCrossfade GnomeBGCrossfade;
-typedef struct _GnomeBGCrossfadeClass GnomeBGCrossfadeClass;
-
-struct _GnomeBGCrossfade
-{
-	GObject parent_object;
-
-	GnomeBGCrossfadePrivate *priv;
-};
-
-struct _GnomeBGCrossfadeClass
-{
-	GObjectClass parent_class;
-
-	void (* finished) (GnomeBGCrossfade *fade, GdkWindow *window);
-};
-
-G_DEFINE_AUTOPTR_CLEANUP_FUNC(GnomeBGCrossfade, g_object_unref)
-
-GType             gnome_bg_crossfade_get_type              (void);
-GnomeBGCrossfade *gnome_bg_crossfade_new (int width, int height);
-gboolean          gnome_bg_crossfade_set_start_surface (GnomeBGCrossfade *fade,
-                                                        cairo_surface_t *surface);
-gboolean          gnome_bg_crossfade_set_end_surface (GnomeBGCrossfade *fade,
-                                                      cairo_surface_t *surface);
-void              gnome_bg_crossfade_start (GnomeBGCrossfade *fade,
-                                            GdkWindow        *window);
-gboolean          gnome_bg_crossfade_is_started (GnomeBGCrossfade *fade);
-void              gnome_bg_crossfade_stop (GnomeBGCrossfade *fade);
-
-G_END_DECLS
-
-#endif
diff --git a/libgnome-desktop/gnome-bg.c b/libgnome-desktop/gnome-bg.c
index 6a453b63..96f5cb78 100644
--- a/libgnome-desktop/gnome-bg.c
+++ b/libgnome-desktop/gnome-bg.c
@@ -40,7 +40,6 @@ Author: Soren Sandmann <sandmann@redhat.com>
 #define GNOME_DESKTOP_USE_UNSTABLE_API
 #include "gnome-bg.h"
 #include "gnome-bg-slide-show.h"
-#include "gnome-bg-crossfade.h"
 
 #define BG_KEY_PRIMARY_COLOR      "primary-color"
 #define BG_KEY_SECONDARY_COLOR    "secondary-color"
@@ -148,7 +147,7 @@ static gboolean   is_different         (GnomeBG               *bg,
 static time_t     get_mtime            (const char            *filename);
 static GdkPixbuf *create_img_thumbnail (GnomeBG               *bg,
 					GnomeDesktopThumbnailFactory *factory,
-					GdkScreen             *screen,
+					GdkDisplay             *display,
 					int                    dest_width,
 					int                    dest_height,
 					int		       frame_num);
@@ -879,7 +878,7 @@ draw_once (GnomeBG   *bg,
 	GdkPixbuf   *pixbuf;
 	gint         num_monitor;
 
-	/* we just draw on the whole screen */
+	/* we just draw on the whole display */
 	num_monitor = 0;
 
 	rect.x = 0;
@@ -972,17 +971,17 @@ gnome_bg_get_pixmap_size (GnomeBG   *bg,
 /**
  * gnome_bg_create_surface:
  * @bg: GnomeBG 
- * @window: 
+ * @surface: 
  * @width: 
  * @height:
  *
- * Create a surface that can be set as background for @window.
+ * Create a surface that can be set as background for @surface.
  *
  * Returns: %NULL on error (e.g. out of X connections)
  **/
 cairo_surface_t *
 gnome_bg_create_surface (GnomeBG	    *bg,
-		 	 GdkWindow   *window,
+		 	 GdkSurface   *gdk_surface,
 			 int	     width,
 			 int	     height)
 {
@@ -992,9 +991,9 @@ gnome_bg_create_surface (GnomeBG	    *bg,
 	cairo_t *cr;
 	
 	g_return_val_if_fail (bg != NULL, NULL);
-	g_return_val_if_fail (window != NULL, NULL);
+	g_return_val_if_fail (surface != NULL, NULL);
 
-	scale = gdk_window_get_scale_factor (window);
+	scale = gdk_monitor_get_scale_factor (gdk_surface);
 
         if (bg->pixbuf_cache &&
             gdk_pixbuf_get_width (bg->pixbuf_cache) != width &&
@@ -1005,7 +1004,7 @@ gnome_bg_create_surface (GnomeBG	    *bg,
 
 	/* has the side effect of loading and caching pixbuf only when in tile mode */
 	gnome_bg_get_pixmap_size (bg, width, height, &pm_width, &pm_height);
-	surface = gdk_window_create_similar_surface (window,
+	surface = gdk_surface_create_similar_surface (gdk_surface,
                                                      CAIRO_CONTENT_COLOR,
                                                      pm_width, pm_height);
 
@@ -1018,16 +1017,16 @@ gnome_bg_create_surface (GnomeBG	    *bg,
 	}
 	else {
 		GdkPixbuf *pixbuf;
-		cairo_surface_t *pixbuf_surface;
+		// cairo_surface_t *pixbuf_surface;
 		
 		pixbuf = gdk_pixbuf_new (GDK_COLORSPACE_RGB, FALSE, 8,
 					 scale * width, scale * height);
 		gnome_bg_draw (bg, pixbuf);
 
-		pixbuf_surface = gdk_cairo_surface_create_from_pixbuf (pixbuf, 0, window);
-		cairo_set_source_surface (cr, pixbuf_surface, 0, 0);
+	    // pixbuf_surface = gdk_cairo_region_create_from_surface (surface);
+		gdk_cairo_set_source_pixbuf (cr, pixbuf, 0, 0);
 
-		cairo_surface_destroy (pixbuf_surface);
+	    // cairo_surface_destroy (pixbuf_surface);
 		g_object_unref (pixbuf);
 	}
 
@@ -1164,7 +1163,7 @@ fit_factor (int from_width, int from_height,
 GdkPixbuf *
 gnome_bg_create_thumbnail (GnomeBG               *bg,
 		           GnomeDesktopThumbnailFactory *factory,
-			   GdkScreen             *screen,
+			   GdkDisplay             *display,
 			   int                    dest_width,
 			   int                    dest_height)
 {
@@ -1178,7 +1177,7 @@ gnome_bg_create_thumbnail (GnomeBG               *bg,
 	draw_color (bg, result);
 	
 	if (bg->placement != G_DESKTOP_BACKGROUND_STYLE_NONE) {
-		thumb = create_img_thumbnail (bg, factory, screen, dest_width, dest_height, -1);
+		thumb = create_img_thumbnail (bg, factory, display, dest_width, dest_height, -1);
 		
 		if (thumb) {
 			draw_image_for_thumb (bg, thumb, result);
@@ -1566,7 +1565,7 @@ static GdkPixbuf *
 scale_thumbnail (GDesktopBackgroundStyle placement,
 		 const char *filename,
 		 GdkPixbuf *thumb,
-		 GdkScreen *screen,
+		 GdkDisplay *display,
 		 int	    dest_width,
 		 int	    dest_height)
 {
@@ -1584,9 +1583,21 @@ scale_thumbnail (GDesktopBackgroundStyle placement,
 	
 	if (get_thumb_annotations (thumb, &o_width, &o_height)		||
 	    (filename && get_original_size (filename, &o_width, &o_height))) {
-		
-		int scr_height = gdk_screen_get_height (screen);
-		int scr_width = gdk_screen_get_width (screen);
+
+		GListModel* monitors = gdk_display_get_monitors (display);
+		GdkMonitor *monitor;
+		GdkRectangle scr_rect = { 0, };
+		int i = 0;
+		for (i = 1; i < g_list_model_get_n_items (monitors); i++) {
+    		GdkRectangle rect;
+    		monitor = g_list_model_get_item (monitors, i);
+    		gdk_monitor_get_geometry (monitor, &rect);
+    		gdk_rectangle_union (&scr_rect, &rect, &scr_rect);
+    		g_object_unref (monitor);
+  		}
+		int scr_height = scr_rect.height;
+		int scr_width = scr_rect.width;
+
 		int thumb_width = gdk_pixbuf_get_width (thumb);
 		int thumb_height = gdk_pixbuf_get_height (thumb);
 		double screen_to_dest = fit_factor (scr_width, scr_height,
@@ -1630,7 +1641,7 @@ scale_thumbnail (GDesktopBackgroundStyle placement,
 static GdkPixbuf *
 create_img_thumbnail (GnomeBG                      *bg,
 		      GnomeDesktopThumbnailFactory *factory,
-		      GdkScreen                    *screen,
+		      GdkDisplay                    *display,
 		      int                           dest_width,
 		      int                           dest_height,
 		      int                           frame_num)
@@ -1645,7 +1656,7 @@ create_img_thumbnail (GnomeBG                      *bg,
 			result = scale_thumbnail (bg->placement,
 						  bg->filename,
 						  thumb,
-						  screen,
+						  display,
 						  dest_width,
 						  dest_height);
 			g_object_unref (thumb);
@@ -1688,7 +1699,7 @@ create_img_thumbnail (GnomeBG                      *bg,
 						thumb = scale_thumbnail (bg->placement,
 									 file1,
 									 tmp,
-									 screen,
+									 display,
 									 dest_width,
 									 dest_height);
 						g_object_unref (tmp);
@@ -1705,14 +1716,14 @@ create_img_thumbnail (GnomeBG                      *bg,
 						thumb1 = scale_thumbnail (bg->placement,
 									  file1,
 									  p1,
-									  screen,
+									  display,
 									  dest_width,
 									  dest_height);
 
 						thumb2 = scale_thumbnail (bg->placement,
 									  file2,
 									  p2,
-									  screen,
+									  display,
 									  dest_width,
 									  dest_height);
 
@@ -2268,7 +2279,7 @@ gnome_bg_changes_with_time (GnomeBG *bg)
 GdkPixbuf *
 gnome_bg_create_frame_thumbnail (GnomeBG			*bg,
 				 GnomeDesktopThumbnailFactory	*factory,
-				 GdkScreen			*screen,
+				 GdkDisplay			*display,
 				 int				 dest_width,
 				 int				 dest_height,
 				 int				 frame_num)
@@ -2304,7 +2315,7 @@ gnome_bg_create_frame_thumbnail (GnomeBG			*bg,
 	draw_color (bg, result);
 
 	if (bg->placement != G_DESKTOP_BACKGROUND_STYLE_NONE) {
-		thumb = create_img_thumbnail (bg, factory, screen, dest_width, dest_height, frame_num + skipped);
+		thumb = create_img_thumbnail (bg, factory, display, dest_width, dest_height, frame_num + skipped);
 
 		if (thumb) {
 			draw_image_for_thumb (bg, thumb, result);
diff --git a/libgnome-desktop/gnome-bg.h b/libgnome-desktop/gnome-bg.h
index a51ccbee..fd6d18c9 100644
--- a/libgnome-desktop/gnome-bg.h
+++ b/libgnome-desktop/gnome-bg.h
@@ -33,7 +33,6 @@
 #include <gio/gio.h>
 #include <gdesktop-enums.h>
 #include <libgnome-desktop/gnome-desktop-thumbnail.h>
-#include <libgnome-desktop/gnome-bg-crossfade.h>
 #include <gdesktop-enums.h>
 
 G_BEGIN_DECLS
@@ -78,7 +77,7 @@ const gchar *    gnome_bg_get_filename          (GnomeBG               *bg);
 void             gnome_bg_draw                  (GnomeBG               *bg,
 						 GdkPixbuf             *dest);
 cairo_surface_t *gnome_bg_create_surface        (GnomeBG               *bg,
-						 GdkWindow             *window,
+						 GdkSurface             *surface,
 						 int                    width,
 						 int                    height);
 gboolean         gnome_bg_get_image_size        (GnomeBG               *bg,
@@ -89,7 +88,7 @@ gboolean         gnome_bg_get_image_size        (GnomeBG               *bg,
 						 int                   *height);
 GdkPixbuf *      gnome_bg_create_thumbnail      (GnomeBG               *bg,
 						 GnomeDesktopThumbnailFactory *factory,
-						 GdkScreen             *screen,
+						 GdkDisplay             *screen,
 						 int                    dest_width,
 						 int                    dest_height);
 gboolean         gnome_bg_is_dark               (GnomeBG               *bg,
@@ -99,7 +98,7 @@ gboolean         gnome_bg_has_multiple_sizes    (GnomeBG               *bg);
 gboolean         gnome_bg_changes_with_time     (GnomeBG               *bg);
 GdkPixbuf *      gnome_bg_create_frame_thumbnail (GnomeBG              *bg,
 						 GnomeDesktopThumbnailFactory *factory,
-						 GdkScreen             *screen,
+						 GdkDisplay             *screen,
 						 int                    dest_width,
 						 int                    dest_height,
 						 int                    frame_num);
diff --git a/libgnome-desktop/gnome-desktop-3.0-uninstalled.pc.in b/libgnome-desktop/gnome-desktop-4.0-uninstalled.pc.in
index 2f1c6803..9587196d 100644
--- a/libgnome-desktop/gnome-desktop-3.0-uninstalled.pc.in
+++ b/libgnome-desktop/gnome-desktop-4.0-uninstalled.pc.in
@@ -3,9 +3,9 @@ exec_prefix=@exec_prefix@
 libdir=@libdir@
 includedir=@includedir@
 
-Name: gnome-desktop-3.0
+Name: gnome-desktop-4.0
 Description: Utility library for loading .desktop files
-Requires: gtk+-3.0 gsettings-desktop-schemas
+Requires: gtk4 gsettings-desktop-schemas
 Version: @VERSION@
 Libs: ${pc_top_builddir}/${pcfiledir}/libgnome-desktop-3.la
 Cflags: -I${pc_top_builddir}/${pcfiledir}/..
diff --git a/libgnome-desktop/gnome-desktop-3.0.pc.in b/libgnome-desktop/gnome-desktop-4.0.pc.in
index a9cef937..eb947128 100644
--- a/libgnome-desktop/gnome-desktop-3.0.pc.in
+++ b/libgnome-desktop/gnome-desktop-4.0.pc.in
@@ -3,9 +3,9 @@ exec_prefix=@exec_prefix@
 libdir=@libdir@
 includedir=@includedir@
 
-Name: gnome-desktop-3.0
+Name: gnome-desktop-4.0
 Description: Utility library for loading .desktop files
-Requires: gtk+-3.0 gsettings-desktop-schemas
+Requires: gtk4 gsettings-desktop-schemas
 Version: @VERSION@
 Libs: -L${libdir} -lgnome-desktop-3
-Cflags: -I${includedir}/gnome-desktop-3.0
+Cflags: -I${includedir}/gnome-desktop-4.0
diff --git a/libgnome-desktop/gnome-idle-monitor.c b/libgnome-desktop/gnome-idle-monitor.c
index b481c670..f9d8e71f 100644
--- a/libgnome-desktop/gnome-idle-monitor.c
+++ b/libgnome-desktop/gnome-idle-monitor.c
@@ -26,9 +26,6 @@
 #include <glib.h>
 #include <glib/gi18n-lib.h>
 #include <gdk/gdk.h>
-#if defined(GDK_WINDOWING_WAYLAND)
-#include <gdk/gdkwayland.h>
-#endif
 
 #define GNOME_DESKTOP_USE_UNSTABLE_API
 #include "gnome-idle-monitor.h"
diff --git a/libgnome-desktop/gnome-rr-debug.c b/libgnome-desktop/gnome-rr-debug.c
index af578829..86226434 100644
--- a/libgnome-desktop/gnome-rr-debug.c
+++ b/libgnome-desktop/gnome-rr-debug.c
@@ -148,8 +148,8 @@ main (int argc, char *argv[])
 	GnomeRRScreen *screen;
 	guint i;
 
-	gtk_init (&argc, &argv);
-	screen = gnome_rr_screen_new (gdk_screen_get_default (), &error);
+	gtk_init ();
+	screen = gnome_rr_screen_new (gdk_display_get_default (), &error);
 	if (screen == NULL) {
 		g_warning ("failed to get screen: %s", error->message);
 		g_error_free (error);
@@ -164,7 +164,8 @@ main (int argc, char *argv[])
 	g_signal_connect (screen, "output-connected", G_CALLBACK (output_connected), NULL);
 	g_signal_connect (screen, "notify::dpms-mode", G_CALLBACK (dpms_mode_changed), NULL);
 
-	gtk_main ();
+	GMainLoop *loop = g_main_loop_new (NULL, FALSE);
+	g_main_loop_run(loop);
 
 out:
 	g_object_unref (screen);
diff --git a/libgnome-desktop/gnome-rr-private.h b/libgnome-desktop/gnome-rr-private.h
index 36ad7767..bd5a8dcd 100644
--- a/libgnome-desktop/gnome-rr-private.h
+++ b/libgnome-desktop/gnome-rr-private.h
@@ -1,20 +1,7 @@
 #ifndef GNOME_RR_PRIVATE_H
 #define GNOME_RR_PRIVATE_H
 
-#ifdef GDK_WINDOWING_WAYLAND
-#include <gdk/gdkwayland.h>
-#else
-enum wl_output_transform {
-  WL_OUTPUT_TRANSFORM_NORMAL,
-  WL_OUTPUT_TRANSFORM_90,
-  WL_OUTPUT_TRANSFORM_180,
-  WL_OUTPUT_TRANSFORM_270,
-  WL_OUTPUT_TRANSFORM_FLIPPED,
-  WL_OUTPUT_TRANSFORM_FLIPPED_90,
-  WL_OUTPUT_TRANSFORM_FLIPPED_180,
-  WL_OUTPUT_TRANSFORM_FLIPPED_270
-};
-#endif
+#include <gdk/wayland/gdkwayland.h>
 
 #include "meta-xrandr-shared.h"
 #include "meta-dbus-xrandr.h"
@@ -43,8 +30,8 @@ struct ScreenInfo
 
 struct GnomeRRScreenPrivate
 {
-    GdkScreen *			gdk_screen;
-    GdkWindow *			gdk_root;
+    GdkDisplay *			gdk_screen;
+    GdkSurface *			gdk_root;
     ScreenInfo *		info;
 
     int                         init_name_watch_id;
diff --git a/libgnome-desktop/gnome-rr.c b/libgnome-desktop/gnome-rr.c
index 692dafaa..e4373989 100644
--- a/libgnome-desktop/gnome-rr.c
+++ b/libgnome-desktop/gnome-rr.c
@@ -42,7 +42,7 @@
 
 enum {
     SCREEN_PROP_0,
-    SCREEN_PROP_GDK_SCREEN,
+    SCREEN_PROP_GDK_DISPLAY,
     SCREEN_PROP_DPMS_MODE,
     SCREEN_PROP_LAST,
 };
@@ -834,7 +834,7 @@ gnome_rr_screen_set_property (GObject *gobject, guint property_id, const GValue
 
     switch (property_id)
     {
-    case SCREEN_PROP_GDK_SCREEN:
+    case SCREEN_PROP_GDK_DISPLAY:
         priv->gdk_screen = g_value_get_object (value);
         return;
     case SCREEN_PROP_DPMS_MODE:
@@ -854,7 +854,7 @@ gnome_rr_screen_get_property (GObject *gobject, guint property_id, GValue *value
 
     switch (property_id)
     {
-    case SCREEN_PROP_GDK_SCREEN:
+    case SCREEN_PROP_GDK_DISPLAY:
         g_value_set_object (value, priv->gdk_screen);
         return;
     case SCREEN_PROP_DPMS_MODE: {
@@ -885,12 +885,12 @@ gnome_rr_screen_class_init (GnomeRRScreenClass *klass)
 
     g_object_class_install_property(
             gobject_class,
-            SCREEN_PROP_GDK_SCREEN,
+            SCREEN_PROP_GDK_DISPLAY,
             g_param_spec_object (
-                    "gdk-screen",
-                    "GDK Screen",
-                    "The GDK Screen represented by this GnomeRRScreen",
-                    GDK_TYPE_SCREEN,
+                    "gdk-display",
+                    "GDK Display",
+                    "The GDK Display represented by this GnomeRRScreen",
+                    GDK_TYPE_DISPLAY,
                     G_PARAM_READWRITE |
 		    G_PARAM_CONSTRUCT_ONLY |
 		    G_PARAM_STATIC_STRINGS)
@@ -983,43 +983,43 @@ gnome_rr_screen_init (GnomeRRScreen *self)
     self->priv = gnome_rr_screen_get_instance_private (self);
 }
 
-/* Weak reference callback set in gnome_rr_screen_new(); we remove the GObject data from the GdkScreen. */
+/* Weak reference callback set in gnome_rr_screen_new(); we remove the GObject data from the GdkDisplay. */
 static void
 rr_screen_weak_notify_cb (gpointer data, GObject *where_the_object_was)
 {
-    GdkScreen *screen = GDK_SCREEN (data);
+    GdkDisplay *display = GDK_DISPLAY (data);
 
-    g_object_set_data (G_OBJECT (screen), "GnomeRRScreen", NULL);
+    g_object_set_data (G_OBJECT (display), "GnomeRRScreen", NULL);
 }
 
 /**
  * gnome_rr_screen_new:
- * @screen: the #GdkScreen on which to operate
+ * @screen: the #GdkDisplay on which to operate
  * @error: will be set if XRandR is not supported
  *
  * Creates a unique #GnomeRRScreen instance for the specified @screen.
  *
  * Returns: a unique #GnomeRRScreen instance, specific to the @screen, or NULL
  * if this could not be created, for instance if the driver does not support
- * Xrandr 1.2.  Each #GdkScreen thus has a single instance of #GnomeRRScreen.
+ * Xrandr 1.2.  Each #GdkDisplay thus has a single instance of #GnomeRRScreen.
  */
 GnomeRRScreen *
-gnome_rr_screen_new (GdkScreen *screen,
+gnome_rr_screen_new (GdkDisplay *display,
 		     GError **error)
 {
     GnomeRRScreen *rr_screen;
 
-    g_return_val_if_fail (GDK_IS_SCREEN (screen), NULL);
+    g_return_val_if_fail (GDK_IS_DISPLAY (display), NULL);
     g_return_val_if_fail (error == NULL || *error == NULL, NULL);
 
-    rr_screen = g_object_get_data (G_OBJECT (screen), "GnomeRRScreen");
+    rr_screen = g_object_get_data (G_OBJECT (display), "GnomeRRScreen");
     if (rr_screen)
 	g_object_ref (rr_screen);
     else {
-	rr_screen = g_initable_new (GNOME_TYPE_RR_SCREEN, NULL, error, "gdk-screen", screen, NULL);
+	rr_screen = g_initable_new (GNOME_TYPE_RR_SCREEN, NULL, error, "gdk-display", display, NULL);
 	if (rr_screen) {
-	    g_object_set_data (G_OBJECT (screen), "GnomeRRScreen", rr_screen);
-	    g_object_weak_ref (G_OBJECT (rr_screen), rr_screen_weak_notify_cb, screen);
+	    g_object_set_data (G_OBJECT (display), "GnomeRRScreen", rr_screen);
+	    g_object_weak_ref (G_OBJECT (rr_screen), rr_screen_weak_notify_cb, display);
 	}
     }
 
@@ -1027,15 +1027,15 @@ gnome_rr_screen_new (GdkScreen *screen,
 }
 
 void
-gnome_rr_screen_new_async (GdkScreen           *screen,
+gnome_rr_screen_new_async (GdkDisplay           *display,
                            GAsyncReadyCallback  callback,
                            gpointer             user_data)
 {
-    g_return_if_fail (GDK_IS_SCREEN (screen));
+    g_return_if_fail (GDK_IS_DISPLAY (display));
 
     g_async_initable_new_async (GNOME_TYPE_RR_SCREEN, G_PRIORITY_DEFAULT,
                                 NULL, callback, user_data,
-                                "gdk-screen", screen, NULL);
+                                "gdk-display", display, NULL);
 }
 
 GnomeRRScreen *
diff --git a/libgnome-desktop/gnome-rr.h b/libgnome-desktop/gnome-rr.h
index 7b5c92d4..206f7bc2 100644
--- a/libgnome-desktop/gnome-rr.h
+++ b/libgnome-desktop/gnome-rr.h
@@ -117,9 +117,9 @@ GType gnome_rr_mode_get_type (void);
 GType gnome_rr_dpms_mode_get_type (void);
 
 /* GnomeRRScreen */
-GnomeRRScreen * gnome_rr_screen_new                (GdkScreen             *screen,
+GnomeRRScreen * gnome_rr_screen_new                (GdkDisplay             *screen,
 						    GError               **error);
-void            gnome_rr_screen_new_async          (GdkScreen             *screen,
+void            gnome_rr_screen_new_async          (GdkDisplay             *screen,
                                                     GAsyncReadyCallback    callback,
                                                     gpointer               user_data);
 GnomeRRScreen * gnome_rr_screen_new_finish         (GAsyncResult          *result,
diff --git a/libgnome-desktop/meson.build b/libgnome-desktop/meson.build
index 483f1ff6..86c9497c 100644
--- a/libgnome-desktop/meson.build
+++ b/libgnome-desktop/meson.build
@@ -13,7 +13,6 @@ introspection_sources = [
   'gnome-desktop-thumbnail.c',
   'gnome-bg.c',
   'gnome-bg-slide-show.c',
-  'gnome-bg-crossfade.c',
   'gnome-rr.c',
   'gnome-rr-config.c',
   'gnome-rr-output-info.c',
@@ -53,7 +52,6 @@ libgnome_desktop_sources = [
 
 libgnome_desktop_headers = [
   'gnome-bg.h',
-  'gnome-bg-crossfade.h',
   'gnome-bg-slide-show.h',
   'gnome-desktop-thumbnail.h',
   'gnome-rr.h',
@@ -67,7 +65,7 @@ libgnome_desktop_headers = [
 ]
 
 install_headers(libgnome_desktop_headers,
-  subdir: 'gnome-desktop-3.0/libgnome-desktop'
+  subdir: 'gnome-desktop-4.0/libgnome-desktop'
 )
 
 gnome_desktop_deps = [
@@ -109,10 +107,10 @@ libgnome_desktop_dep = declare_dependency(
 
 gnome.generate_gir(libgnome_desktop,
   sources: introspection_sources + libgnome_desktop_headers,
-  export_packages: 'gnome-desktop-3.0',
+  export_packages: 'gnome-desktop-4.0',
   namespace: 'GnomeDesktop',
-  nsversion: '3.0',
-  includes: ['GObject-2.0', 'Gtk-3.0', 'GDesktopEnums-3.0'],
+  nsversion: '4.0',
+  includes: ['GObject-2.0', 'Gtk-4.0', 'GDesktopEnums-3.0'],
   extra_args: '-DGNOME_DESKTOP_USE_UNSTABLE_API',
   identifier_prefix: 'Gnome',
   symbol_prefix: 'gnome',
@@ -121,12 +119,12 @@ gnome.generate_gir(libgnome_desktop,
 
 desktop_pc = pkg.generate(
   libraries: libgnome_desktop,
-  requires: ['gtk+-3.0', 'gsettings-desktop-schemas'],
+  requires: ['gtk4', 'gsettings-desktop-schemas'],
   version: meson.project_version(),
-  name: 'gnome-desktop-3.0',
-  filebase: 'gnome-desktop-3.0',
+  name: 'gnome-desktop-4.0',
+  filebase: 'gnome-desktop-4.0',
   description: 'Utility library for loading .desktop files',
-  subdirs: 'gnome-desktop-3.0'
+  subdirs: 'gnome-desktop-4.0'
 )
 
 test_programs = [
diff --git a/libgnome-desktop/test-idle-monitor.c b/libgnome-desktop/test-idle-monitor.c
index 713f12cf..b366364f 100644
--- a/libgnome-desktop/test-idle-monitor.c
+++ b/libgnome-desktop/test-idle-monitor.c
@@ -38,7 +38,7 @@ int main (int argc, char **argv)
 	GnomeIdleMonitor *monitor;
 	guint watch_id;
 
-	gtk_init (&argc, &argv);
+	gtk_init ();
 
 	monitor = gnome_idle_monitor_new ();
 	watch_id = gnome_idle_monitor_add_idle_watch (monitor,
@@ -51,7 +51,8 @@ int main (int argc, char **argv)
 
 	ensure_active_watch (monitor);
 
-	gtk_main ();
+	GMainLoop *loop = g_main_loop_new (NULL, FALSE);
+	g_main_loop_run(loop);
 
 	return 0;
 }
diff --git a/meson.build b/meson.build
index 2ec66471..220c1858 100644
--- a/meson.build
+++ b/meson.build
@@ -1,6 +1,6 @@
 project('gnome-desktop', 'c',
   meson_version: '>= 0.49.0',
-  version: '3.38.0',
+  version: '40.alpha',
   license: ['GPL2+', 'LGPL2+']
 )
 
@@ -14,11 +14,11 @@ project('gnome-desktop', 'c',
 # to 0. When bumping the second version, set the third one to zero.
 #
 # A lot easier than libtool, right?
-libversion = '19.0.8'
+libversion = '20.0.0'
 soversion = libversion.split('.')[0]
 
 gdk_pixbuf_req = '>= 2.36.5'
-gtk_req = '>= 3.3.6'
+gtk_req = '>= 4.0.0'
 glib_req = '>= 2.53.0'
 xrandr_req = '>= 1.3'
 schemas_req = '>= 3.27.0'
@@ -40,7 +40,7 @@ test_execdir = join_paths(libexecdir, 'installed-tests', meson.project_name())
 versiondir = join_paths(datadir, 'gnome')
 
 gdk_pixbuf_dep = dependency('gdk-pixbuf-2.0', version: gdk_pixbuf_req)
-gtk_dep = dependency('gtk+-3.0', version: gtk_req)
+gtk_dep = dependency('gtk4', version: gtk_req)
 glib_dep = dependency('glib-2.0', version: glib_req)
 gio_dep = dependency('gio-2.0', version: glib_req)
 gio_unix_dep = dependency('gio-unix-2.0', version: glib_req)
@@ -81,7 +81,7 @@ endif
 
 conf = configuration_data()
 
-conf.set_quoted('GETTEXT_PACKAGE', '@0@-3.0'.format(meson.project_name()))
+conf.set_quoted('GETTEXT_PACKAGE', '@0@-4.0'.format(meson.project_name()))
 conf.set_quoted('INSTALL_PREFIX', prefix)
 
 conf.set('ENABLE_SECCOMP', seccomp_dep.found())
@@ -109,7 +109,7 @@ version_conf = configuration_data()
 
 version_conf.set('GNOME_PLATFORM', version_array[0])
 version_conf.set('GNOME_MINOR', version_array[1])
-version_conf.set('GNOME_MICRO', version_array[2])
+version_conf.set('GNOME_MICRO', 0)
 version_conf.set('GNOME_DISTRIBUTOR', get_option('gnome_distributor'))
 
 if get_option('date_in_gnome_version')
@@ -141,5 +141,5 @@ if get_option('desktop_docs')
 endif
 
 if get_option('gtk_doc')
-  subdir('docs/reference/gnome-desktop3')
+  subdir('docs/reference/gnome-desktop4')
 endif
diff --git a/po/Makevars b/po/Makevars
index aeb45289..ef11e1ba 100644
--- a/po/Makevars
+++ b/po/Makevars
@@ -1,7 +1,7 @@
 # Makefile variables for PO directory in any package using GNU gettext.
 
 # Usually the message domain is the same as the package name.
-DOMAIN = gnome-desktop-3.0
+DOMAIN = gnome-desktop-4.0
 
 # These two variables depend on the location of this directory.
 subdir = po
diff --git a/po/meson.build b/po/meson.build
index d1fa7c6f..a9e15ce8 100644
--- a/po/meson.build
+++ b/po/meson.build
@@ -1 +1 @@
-i18n.gettext('gnome-desktop-3.0', preset: 'glib')
+i18n.gettext('gnome-desktop-4.0', preset: 'glib')
diff --git a/tests/wallclock-reftest.c b/tests/wallclock-reftest.c
index 1238ea89..99a19b06 100644
--- a/tests/wallclock-reftest.c
+++ b/tests/wallclock-reftest.c
@@ -93,9 +93,8 @@ add_extra_css (const char *testname,
 
   provider = GTK_STYLE_PROVIDER (gtk_css_provider_new ());
   gtk_css_provider_load_from_path (GTK_CSS_PROVIDER (provider),
-                                   css_file,
-                                   NULL);
-  gtk_style_context_add_provider_for_screen (gdk_screen_get_default (),
+                                   css_file);
+  gtk_style_context_add_provider_for_display (gdk_display_get_default (),
                                              provider,
                                              GTK_STYLE_PROVIDER_PRIORITY_FORCE);
 
@@ -110,7 +109,7 @@ remove_extra_css (GtkStyleProvider *provider)
   if (provider == NULL)
     return;
 
-  gtk_style_context_remove_provider_for_screen (gdk_screen_get_default (),
+  gtk_style_context_remove_provider_for_display (gdk_display_get_default (),
                                                 provider);
 }
 
@@ -144,30 +143,26 @@ quit_when_idle (gpointer loop)
   return G_SOURCE_REMOVE;
 }
 
-static void
-event_handler_func (GdkEvent *event,
-                    gpointer  data)
+static gboolean
+check_for_draw (GdkSurface  *surface,
+               cairo_region_t *region,
+               gpointer    user_data)
 {
-    gtk_main_do_event (event);
-}
+  GdkEvent *event = (GdkEvent*)event;
+  GMainLoop *loop = (GMainLoop*)user_data;
 
-static void
-check_for_draw (GdkEvent *event, gpointer loop)
-{
-  if (event->type == GDK_EXPOSE)
-    {
-      g_idle_add (quit_when_idle, loop);
-      gdk_event_handler_set ((GdkEventFunc) event_handler_func, NULL, NULL);
-    }
+  g_idle_add (quit_when_idle, loop);
+  
+  g_object_disconnect(surface, "render", check_for_draw, loop, NULL);
 
-  gtk_main_do_event (event);
+  return FALSE;
 }
 
 static cairo_surface_t *
 snapshot_widget (GtkWidget *widget, SnapshotMode mode)
 {
   cairo_surface_t *surface;
-  cairo_pattern_t *bg;
+  // cairo_pattern_t *bg;
   GMainLoop *loop;
   cairo_t *cr;
 
@@ -179,43 +174,50 @@ snapshot_widget (GtkWidget *widget, SnapshotMode mode)
    * happen if the window is fully obscured by windowed child widgets.
    * Alternatively, we could wait for an expose event on widget's window.
    * Both of these are rather hairy, not sure what's best. */
-  gdk_event_handler_set (check_for_draw, loop, NULL);
-  g_main_loop_run (loop);
-
-  surface = gdk_window_create_similar_surface (gtk_widget_get_window (widget),
+  
+  GtkNative* native = gtk_widget_get_native(widget);
+  GdkSurface* gdk_surface = gtk_native_get_surface(native);
+  surface = gdk_surface_create_similar_surface (gdk_surface,
                                                CAIRO_CONTENT_COLOR,
                                                gtk_widget_get_allocated_width (widget),
                                                gtk_widget_get_allocated_height (widget));
 
+  g_object_connect(surface, "render", check_for_draw, loop, NULL);
+  g_main_loop_run (loop);
+  
   cr = cairo_create (surface);
 
   switch (mode)
     {
     case SNAPSHOT_WINDOW:
       {
-        GdkWindow *window = gtk_widget_get_window (widget);
-        if (gdk_window_get_window_type (window) == GDK_WINDOW_TOPLEVEL ||
-            gdk_window_get_window_type (window) == GDK_WINDOW_FOREIGN)
+        GtkNative *native = gtk_widget_get_native (widget);
+        // TODO: native can be NULL?
+        GdkSurface *surface= gtk_native_get_surface (native);
+        cairo_surface_t* cairo_surface = gdk_surface_create_similar_surface(surface, CAIRO_CONTENT_COLOR, gtk_widget_get_allocated_width(widget), gtk_widget_get_allocated_height(widget));
+        if (GTK_IS_ROOT(surface) || GTK_IS_NATIVE(surface))
           {
             /* give the WM/server some time to sync. They need it.
              * Also, do use popups instead of toplevls in your tests
              * whenever you can. */
-            gdk_display_sync (gdk_window_get_display (window));
+            gdk_display_sync (gdk_surface_get_display (surface));
             g_timeout_add (500, quit_when_idle, loop);
             g_main_loop_run (loop);
           }
-        gdk_cairo_set_source_window (cr, window, 0, 0);
+        GdkPixbuf* pixbuf = gdk_pixbuf_get_from_surface(cairo_surface, 0, 0, gtk_widget_get_allocated_width(widget), gtk_widget_get_allocated_height(widget));
+        gdk_cairo_set_source_pixbuf (cr, pixbuf, 0, 0);
         cairo_paint (cr);
       }
       break;
     case SNAPSHOT_DRAW:
-      bg = gdk_window_get_background_pattern (gtk_widget_get_window (widget));
-      if (bg)
-        {
-          cairo_set_source (cr, bg);
-          cairo_paint (cr);
-        }
-      gtk_widget_draw (widget, cr);
+      // TODO:
+      // bg = gdk_window_get_background_pattern (gtk_widget_get_window (widget));
+      // if (bg)
+      //   {
+      //     cairo_set_source (cr, bg);
+      //     cairo_paint (cr);
+      //   }
+      // gtk_widget_draw (widget, cr);
       break;
     default:
       g_assert_not_reached();
@@ -224,7 +226,7 @@ snapshot_widget (GtkWidget *widget, SnapshotMode mode)
 
   cairo_destroy (cr);
   g_main_loop_unref (loop);
-  gtk_widget_destroy (widget);
+  g_object_unref (widget);
 
   return surface;
 }
@@ -269,6 +271,34 @@ save_image (cairo_surface_t *surface,
   g_free (filename);
 }
 
+// TODO: Removed from GDK
+gboolean
+__gdk_cairo_get_clip_rectangle (cairo_t      *cr,
+                              GdkRectangle *rect)
+{
+  double x1, y1, x2, y2;
+  gboolean clip_exists;
+
+  cairo_clip_extents (cr, &x1, &y1, &x2, &y2);
+
+  clip_exists = x1 < x2 && y1 < y2;
+
+  if (rect)
+    {
+      x1 = floor (x1);
+      y1 = floor (y1);
+      x2 = ceil (x2);
+      y2 = ceil (y2);
+
+      rect->x      = CLAMP (x1,      G_MININT, G_MAXINT);
+      rect->y      = CLAMP (y1,      G_MININT, G_MAXINT);
+      rect->width  = CLAMP (x2 - x1, G_MININT, G_MAXINT);
+      rect->height = CLAMP (y2 - y1, G_MININT, G_MAXINT);
+    }
+
+  return clip_exists;
+}
+
 static void
 get_surface_size (cairo_surface_t *surface,
                   int             *width,
@@ -278,7 +308,7 @@ get_surface_size (cairo_surface_t *surface,
   cairo_t *cr;
 
   cr = cairo_create (surface);
-  if (!gdk_cairo_get_clip_rectangle (cr, &area))
+  if (!__gdk_cairo_get_clip_rectangle (cr, &area))
     {
       g_assert_not_reached ();
     }
@@ -597,7 +627,7 @@ main (int argc, char **argv)
   g_setenv ("GDK_RENDERING", "image", FALSE);
 
   g_test_init (&argc, &argv, NULL);
-  gtk_init (&argc, &argv);
+  gtk_init ();
 
   basedir = g_getenv ("G_TEST_SRCDIR");
   if (basedir == NULL)