[WIP] Implement gtk-layer-shell for nemo-desktop.

config.h.meson.in

@@ -19,6 +19,8 @@
 #mesondefine HAVE_SELINUX
 // Define to enable pango-1.44 fixes
 #mesondefine HAVE_PANGO_144
+// Define to use gtk-layer-shell
+#mesondefine HAVE_GTK_LAYER_SHELL
 
 
 

debian/control

@@ -21,12 +21,14 @@ Build-Depends:
  libgsf-1-dev,
  libgtk-3-dev (>= 3.10),
  libgtk-3-doc,
+ libgtk-layer-shell-dev,
  libjson-glib-dev (>= 1.6),
  libpango1.0-dev,
  libx11-dev,
  libxapp-dev (>= 2.0.0),
  libxext-dev,
  libxrender-dev,
+ libwayland-dev,
  meson,
  python3,
  python3-gi,

debian/rules

@@ -8,6 +8,7 @@ CONFIGURE_EXTRA_FLAGS = \
 	--buildtype=debugoptimized \
 	-D deprecated_warnings=false \
 	-D gtk_doc=true \
+	-D gtk_layer_shell=true \
 	-D selinux=false
 
 export DEB_LDFLAGS_MAINT_APPEND = -Wl,-z,defs -Wl,-O1 -Wl,--as-needed

meson.build

@@ -133,6 +133,13 @@ if libselinux_enabled
 endif
 conf.set('HAVE_SELINUX', libselinux_enabled)
 
+gtk_layer_shell_enabled = get_option('gtk_layer_shell')
+if gtk_layer_shell_enabled
+  gtk_layer_shell = dependency('gtk-layer-shell-0', version: '>=0.8', required: true)
+  wayland_client = dependency('wayland-client', required: true)
+  conf.set('HAVE_GTK_LAYER_SHELL', gtk_layer_shell.found())
+endif
+
 # make sure pango development files are installed
 pango = dependency('pango', version: '>=1.40.0')
 # check for newer pango for necessary workarounds
@@ -201,6 +208,7 @@ message('\n'.join(['',
 '    exempi  support:        @0@'.format(exempi_enabled),
 '    Tracker support:        @0@'.format(tracker_enabled),
 '    Wayland support:        @0@'.format(cc.has_header('gdk/gdkwayland.h', dependencies: gtk)),
+'    gtk-layer-shell:        @0@'.format(gtk_layer_shell_enabled),
 '',
 '    nemo-extension documentation: @0@'.format(gtkdoc_enabled),
 '    nemo-extension introspection: @0@'.format(true),

meson_options.txt

@@ -12,3 +12,5 @@ option('empty_view', type : 'boolean', value : false,
        description: 'Enable empty view')
 option('tracker',type : 'combo', choices : ['true', 'false', 'auto'], value : 'false',
        description: 'Tracker support')
+option('gtk_layer_shell', type : 'boolean', value : false,
+       description: 'Use gtk-layer-shell to draw desktop on wayland')

src/meson.build

@@ -113,6 +113,11 @@ if libexif_enabled
   nemo_deps += libexif
 endif
 
+if gtk_layer_shell_enabled
+  nemo_deps += gtk_layer_shell
+  nemo_deps += wayland_client
+endif
+
 nemo = executable('nemo',
   nemoCommon_sources + nemoWindow_sources,
   include_directories: [ rootInclude ],

src/nemo-blank-desktop-window.c

@@ -30,6 +30,10 @@
 #include <gio/gio.h>
 #include <glib/gi18n.h>
 
+#ifdef HAVE_GTK_LAYER_SHELL
+#include <gtk-layer-shell/gtk-layer-shell.h>
+#endif
+
 #include <libnemo-private/nemo-desktop-utils.h>
 #include <libnemo-private/nemo-action.h>
 #include <libnemo-private/nemo-file.h>
@@ -402,7 +406,15 @@ nemo_blank_desktop_window_init (NemoBlankDesktopWindow *window)
 
     window->details->popup_menu = NULL;
     window->details->actions_changed_id = 0;
-    gtk_window_set_type_hint (GTK_WINDOW (window), GDK_WINDOW_TYPE_HINT_DESKTOP);
+
+#ifdef HAVE_GTK_LAYER_SHELL
+    if (gtk_layer_is_supported ()) {
+        gtk_layer_init_for_window (GTK_WINDOW (window));
+    } else
+#endif
+    {
+        gtk_window_set_type_hint (GTK_WINDOW (window), GDK_WINDOW_TYPE_HINT_DESKTOP);
+    }
 
     /* Make it easier for themes authors to style the desktop window separately */
     gtk_style_context_add_class (gtk_widget_get_style_context (GTK_WIDGET (window)), "nemo-desktop-window");
@@ -436,7 +448,13 @@ map (GtkWidget *widget)
 {
 	/* Chain up to realize our children */
 	GTK_WIDGET_CLASS (nemo_blank_desktop_window_parent_class)->map (widget);
-	gdk_window_lower (gtk_widget_get_window (widget));
+
+#ifdef HAVE_GTK_LAYER_SHELL
+    if (!gtk_layer_is_layer_window (GTK_WINDOW (widget)))
+#endif
+    {
+        gdk_window_lower (gtk_widget_get_window (widget));
+    }
 
     GdkWindow *window;
     GdkRGBA transparent = { 0, 0, 0, 0 };
@@ -499,6 +517,31 @@ nemo_blank_desktop_window_update_geometry (NemoBlankDesktopWindow *window)
 {
     GdkRectangle rect;
 
+#ifdef HAVE_GTK_LAYER_SHELL
+    if (gtk_layer_is_layer_window (GTK_WINDOW (window))) {
+        GdkDisplay *display = gdk_display_get_default ();
+        GdkMonitor *monitor = gdk_display_get_monitor (display, window->details->monitor);
+
+        DEBUG ("NemoBlankDesktopWindow: using layer-shell for monitor %d",
+               window->details->monitor);
+
+        gtk_layer_set_layer (GTK_WINDOW (window), GTK_LAYER_SHELL_LAYER_BOTTOM);
+        gtk_layer_set_namespace (GTK_WINDOW (window), "nemo-desktop");
+        gtk_layer_set_keyboard_mode (GTK_WINDOW (window), GTK_LAYER_SHELL_KEYBOARD_MODE_NONE);
+        gtk_layer_set_exclusive_zone (GTK_WINDOW (window), 0);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_TOP, TRUE);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_BOTTOM, TRUE);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_LEFT, TRUE);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_RIGHT, TRUE);
+
+        if (monitor) {
+            gtk_layer_set_monitor (GTK_WINDOW (window), monitor);
+        }
+
+        return;
+    }
+#endif
+
     nemo_desktop_manager_get_window_rect_for_monitor (nemo_desktop_manager_get (),
                                                       window->details->monitor,
                                                       &rect);

src/nemo-desktop-main.c

@@ -55,6 +55,47 @@
 
 #ifdef HAVE_GTK_LAYER_SHELL
 #include <gtk-layer-shell/gtk-layer-shell.h>
+#include <wayland-client.h>
+
+static gboolean layer_shell_available = FALSE;
+
+static void
+registry_handle_global (void *data, struct wl_registry *registry,
+                        uint32_t name, const char *interface, uint32_t version)
+{
+    if (g_strcmp0 (interface, "zwlr_layer_shell_v1") == 0)
+        layer_shell_available = TRUE;
+}
+
+static void
+registry_handle_global_remove (void *data, struct wl_registry *registry, uint32_t name)
+{
+}
+
+static const struct wl_registry_listener registry_listener = {
+    registry_handle_global,
+    registry_handle_global_remove,
+};
+
+static gboolean
+check_layer_shell_support (void)
+{
+    struct wl_display *display;
+    struct wl_registry *registry;
+
+    display = wl_display_connect (NULL);
+    if (!display)
+        return FALSE;
+
+    registry = wl_display_get_registry (display);
+    wl_registry_add_listener (registry, &registry_listener, NULL);
+    wl_display_roundtrip (display);
+
+    wl_registry_destroy (registry);
+    wl_display_disconnect (display);
+
+    return layer_shell_available;
+}
 #endif
 
 int
@@ -91,7 +132,20 @@ main (int argc, char *argv[])
 
 	g_set_prgname ("nemo-desktop");
 
+#ifdef HAVE_GTK_LAYER_SHELL
+	if (check_layer_shell_support ())
+	{
+		g_message ("nemo-desktop: using Wayland backend, gtk-layer-shell supported");
+	}
+	else
+	{
+		g_message ("nemo-desktop: Not a Wayland session, or wlr-layer-shell protocol not supported, using X11 backend");
+		gdk_set_allowed_backends ("x11");
+	}
+#else
+	g_message ("nemo-desktop: using X11");
 	gdk_set_allowed_backends ("x11");
+#endif
 
 #ifdef HAVE_EXEMPI
 	xmp_init();

src/nemo-desktop-manager.c

@@ -15,6 +15,10 @@
 #include <gdk/gdkx.h>
 #include <stdio.h>
 
+#ifdef HAVE_GTK_LAYER_SHELL
+#include <gtk-layer-shell.h>
+#endif
+
 #include "libnemo-private/nemo-action-manager.h"
 #include <libnemo-private/nemo-global-preferences.h>
 #include <libnemo-private/nemo-desktop-utils.h>
@@ -629,12 +633,16 @@ fallback_startup_idle_cb (NemoDesktopManager *manager)
 static gboolean
 is_cinnamon_desktop (void)
 {
+    const gchar *session_desktop = g_getenv ("XDG_SESSION_DESKTOP");
+    const gchar *desktop_session = g_getenv ("DESKTOP_SESSION");
 
-    if (g_strcmp0 (g_getenv ("XDG_SESSION_DESKTOP"), "cinnamon") == 0) {
+    if (session_desktop != NULL &&
+        g_strstr_len (session_desktop, -1, "cinnamon") != NULL) {
         return TRUE;
     }
 
-    if (g_strstr_len (g_getenv ("DESKTOP_SESSION"), -1, "cinnamon") != NULL) {
+    if (desktop_session != NULL &&
+        g_strstr_len (desktop_session, -1, "cinnamon") != NULL) {
         return TRUE;
     }
 
@@ -882,13 +890,24 @@ nemo_desktop_manager_get_margins (NemoDesktopManager *manager,
 {
     FETCH_PRIV (manager);
     GdkRectangle work_rect, geometry;
+    gboolean use_layer_shell = FALSE;
+
+#ifdef HAVE_GTK_LAYER_SHELL
+    use_layer_shell = gtk_layer_is_supported ();
+#endif
 
-    /* We don't use margins if we have reliable work area
-     * info (e.g. having an active Cinnamon session) */
+    DEBUG ("NemoDesktopManager get_margins: monitor=%d proxy_owned=%d other_desktop=%d use_layer_shell=%d",
+           monitor, priv->proxy_owned, priv->other_desktop, use_layer_shell);
+
+    /* When Cinnamon is running, we don't use margins because the window is
+     * sized to the work area (X11 mode) or the compositor sizes it to the
+     * workarea (layer-shell mode with exclusive_zone=0). */
 
     if (priv->proxy_owned && !priv->other_desktop) {
         *left = *right = *top = *bottom = 0;
 
+        DEBUG ("NemoDesktopManager get_margins: returning 0 margins (Cinnamon running)");
+
         return;
     }
 

src/nemo-desktop-window.c

@@ -36,6 +36,10 @@
 #include <gio/gio.h>
 #include <glib/gi18n.h>
 
+#ifdef HAVE_GTK_LAYER_SHELL
+#include <gtk-layer-shell/gtk-layer-shell.h>
+#endif
+
 #include <eel/eel-vfs-extensions.h>
 #include <libnemo-private/nemo-file-utilities.h>
 #include <libnemo-private/nemo-icon-names.h>
@@ -177,12 +181,20 @@ nemo_desktop_window_init (NemoDesktopWindow *window)
 	window->details = G_TYPE_INSTANCE_GET_PRIVATE (window, NEMO_TYPE_DESKTOP_WINDOW,
 						       NemoDesktopWindowDetails);
 
-	g_object_set_data (G_OBJECT (window), "is_desktop_window", 
+	g_object_set_data (G_OBJECT (window), "is_desktop_window",
 			   GINT_TO_POINTER (1));
 
 	/* Make it easier for themes authors to style the desktop window separately */
 	gtk_style_context_add_class (gtk_widget_get_style_context (GTK_WIDGET (window)), "nemo-desktop-window");
-    gtk_window_set_type_hint (GTK_WINDOW (window), GDK_WINDOW_TYPE_HINT_DESKTOP);
+
+#ifdef HAVE_GTK_LAYER_SHELL
+    if (gtk_layer_is_supported ()) {
+        gtk_layer_init_for_window (GTK_WINDOW (window));
+    } else
+#endif
+    {
+        gtk_window_set_type_hint (GTK_WINDOW (window), GDK_WINDOW_TYPE_HINT_DESKTOP);
+    }
 }
 
 NemoDesktopWindow *
@@ -230,7 +242,13 @@ map (GtkWidget *widget)
 {
 	/* Chain up to realize our children */
 	GTK_WIDGET_CLASS (nemo_desktop_window_parent_class)->map (widget);
-	gdk_window_lower (gtk_widget_get_window (widget));
+
+#ifdef HAVE_GTK_LAYER_SHELL
+    if (!gtk_layer_is_layer_window (GTK_WINDOW (widget)))
+#endif
+    {
+        gdk_window_lower (gtk_widget_get_window (widget));
+    }
 
     GdkWindow *window;
     GdkRGBA transparent = { 0, 0, 0, 0 };
@@ -335,6 +353,31 @@ nemo_desktop_window_update_geometry (NemoDesktopWindow *window)
 {
     GdkRectangle rect;
 
+#ifdef HAVE_GTK_LAYER_SHELL
+    if (gtk_layer_is_layer_window (GTK_WINDOW (window))) {
+        GdkDisplay *display = gdk_display_get_default ();
+        GdkMonitor *monitor = gdk_display_get_monitor (display, window->details->monitor);
+
+        DEBUG ("NemoDesktopWindow: using layer-shell for monitor %d",
+               window->details->monitor);
+
+        gtk_layer_set_layer (GTK_WINDOW (window), GTK_LAYER_SHELL_LAYER_BOTTOM);
+        gtk_layer_set_namespace (GTK_WINDOW (window), "nemo-desktop");
+        gtk_layer_set_keyboard_mode (GTK_WINDOW (window), GTK_LAYER_SHELL_KEYBOARD_MODE_ON_DEMAND);
+        gtk_layer_set_exclusive_zone (GTK_WINDOW (window), 0);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_TOP, TRUE);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_BOTTOM, TRUE);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_LEFT, TRUE);
+        gtk_layer_set_anchor (GTK_WINDOW (window), GTK_LAYER_SHELL_EDGE_RIGHT, TRUE);
+
+        if (monitor) {
+            gtk_layer_set_monitor (GTK_WINDOW (window), monitor);
+        }
+
+        return;
+    }
+#endif
+
     nemo_desktop_manager_get_window_rect_for_monitor (nemo_desktop_manager_get (),
                                                       window->details->monitor,
                                                       &rect);