gdk: add gdk_window_set_fullscreen_mode()

and gdk_window_get_fullscreen_mode() API to allow
applications to specify if a fullscreen window should
span across all monitors in a multi-monitor setup or
remain on the current monitor where the window is
placed.

Fullscreen mode can be either GDK_FULLSCREEN_ON_ALL_MONITORS
or GDK_FULLSCREEN_ON_CURRENT_MONITOR.

https://bugzilla.gnome.org/show_bug.cgi?id=691856

4 files changed, 86 insertions, 0 deletions

diff --git a/gdk/gdkinternals.h b/gdk/gdkinternals.h
index 35bbb7fe24..0eb4074cb8 100644
--- a/gdk/gdkinternals.h
+++ b/gdk/gdkinternals.h
@@ -221,6 +221,7 @@ struct _GdkWindow
   guint native_visibility : 2; /* the native visibility of a impl windows */
   guint viewable : 1; /* mapped and all parents mapped */
   guint applied_shape : 1;
+  GdkFullscreenMode fullscreen_mode;
 
   /* The GdkWindow that has the impl, ref:ed if another window.
    * This ref is required to keep the wrapper of the impl window alive
diff --git a/gdk/gdkwindow.c b/gdk/gdkwindow.c
index e337d53ae1..7afcd96978 100644
--- a/gdk/gdkwindow.c
+++ b/gdk/gdkwindow.c
@@ -313,6 +313,7 @@ gdk_window_init (GdkWindow *window)
   window->window_type = GDK_WINDOW_CHILD;
 
   window->state = GDK_WINDOW_STATE_WITHDRAWN;
+  window->fullscreen_mode = GDK_FULLSCREEN_ON_CURRENT_MONITOR;
   window->width = 1;
   window->height = 1;
   window->toplevel_window_type = -1;
@@ -10692,6 +10693,67 @@ gdk_window_fullscreen (GdkWindow *window)
 }
 
 /**
+ * gdk_window_set_fullscreen_mode:
+ * @window: a toplevel #GdkWindow
+ * @mode: fullscreen mode
+ *
+ * Specifies whether the @window should span over all monitors (in a multi-head
+ * setup) or only the current monitor when in fullscreen mode.
+ *
+ * The @mode argument is from the #GdkFullscreenMode enumeration.
+ * If #GDK_FULLSCREEN_ON_ALL_MONITORS is specified, the fullscreen @window will
+ * span over all monitors from the #GdkScreen.
+ *
+ * On X11, searches through the list of monitors from the #GdkScreen the ones
+ * which delimit the 4 edges of the entire #GdkScreen and will ask the window
+ * manager to span the @window over these monitors.
+ *
+ * If the XINERAMA extension is not available or not usable, this function
+ * has no effect.
+ *
+ * Not all window managers support this, so you can't rely on the fullscreen
+ * window to span over the multiple monitors when #GDK_FULLSCREEN_ON_ALL_MONITORS
+ * is specified.
+ *
+ * Since: 3.8
+ **/
+void
+gdk_window_set_fullscreen_mode (GdkWindow        *window,
+                                GdkFullscreenMode mode)
+{
+  GdkWindowImplClass *impl_class;
+
+  g_return_if_fail (GDK_IS_WINDOW (window));
+
+  if (window->fullscreen_mode != mode)
+    {
+      window->fullscreen_mode = mode;
+
+      impl_class = GDK_WINDOW_IMPL_GET_CLASS (window->impl);
+      if (impl_class->apply_fullscreen_mode != NULL)
+        impl_class->apply_fullscreen_mode (window);
+    }
+}
+
+/**
+ * gdk_window_get_fullscreen_mode:
+ * @window: a toplevel #GdkWindow
+ *
+ * Obtains the #GdkFullscreenMode of the @window.
+ *
+ * Returns: The #GdkFullscreenMode applied to the window when fullscreen.
+ *
+ * Since: 3.8
+ **/
+GdkFullscreenMode
+gdk_window_get_fullscreen_mode (GdkWindow *window)
+{
+  g_return_val_if_fail (GDK_IS_WINDOW (window), GDK_FULLSCREEN_ON_CURRENT_MONITOR);
+
+  return window->fullscreen_mode;
+}
+
+/**
  * gdk_window_unfullscreen:
  * @window: a toplevel #GdkWindow
  *
diff --git a/gdk/gdkwindow.h b/gdk/gdkwindow.h
index 4a5daf8482..a4fbac022e 100644
--- a/gdk/gdkwindow.h
+++ b/gdk/gdkwindow.h
@@ -317,6 +317,22 @@ typedef enum
 } GdkWindowEdge;
 
 /**
+ * GdkFullscreenMode:
+ * @GDK_FULLSCREEN_ON_CURRENT_MONITOR: Fullscreen on current monitor only.
+ * @GDK_FULLSCREEN_ON_ALL_MONITORS: Span across all monitors when fullscreen.
+ *
+ * Indicates which monitor (in a multi-head setup) a window should span over
+ * when in fullscreen mode.
+ *
+ * Since: 3.8
+ **/
+typedef enum
+{
+  GDK_FULLSCREEN_ON_CURRENT_MONITOR,
+  GDK_FULLSCREEN_ON_ALL_MONITORS
+} GdkFullscreenMode;
+
+/**
  * GdkWindowAttr:
  * @title: title of the window (for toplevel windows)
  * @event_mask: event mask (see gdk_window_set_events())
@@ -773,6 +789,12 @@ void          gdk_window_unstick         (GdkWindow       *window);
 void          gdk_window_maximize        (GdkWindow       *window);
 void          gdk_window_unmaximize      (GdkWindow       *window);
 void          gdk_window_fullscreen      (GdkWindow       *window);
+GDK_AVAILABLE_IN_3_8
+void          gdk_window_set_fullscreen_mode (GdkWindow   *window,
+                                          GdkFullscreenMode mode);
+GDK_AVAILABLE_IN_3_8
+GdkFullscreenMode
+              gdk_window_get_fullscreen_mode (GdkWindow   *window);
 void          gdk_window_unfullscreen    (GdkWindow       *window);
 void          gdk_window_set_keep_above  (GdkWindow       *window,
                                           gboolean         setting);
diff --git a/gdk/gdkwindowimpl.h b/gdk/gdkwindowimpl.h
index e45de49f88..65149e8217 100644
--- a/gdk/gdkwindowimpl.h
+++ b/gdk/gdkwindowimpl.h
@@ -214,6 +214,7 @@ struct _GdkWindowImplClass
   void         (* maximize)             (GdkWindow *window);
   void         (* unmaximize)           (GdkWindow *window);
   void         (* fullscreen)           (GdkWindow *window);
+  void         (* apply_fullscreen_mode) (GdkWindow *window);
   void         (* unfullscreen)         (GdkWindow *window);
   void         (* set_keep_above)       (GdkWindow *window,
 					 gboolean   setting);