window: Make default focus window on each workspace appear focused

Makes workspace transitions in gnome-shell look more seamless, since
both outgoing and incoming workspace have focused windows.

This is only done for click focus mode, since it's not known which
window would be focused for the other modes.

Track the state and recompute it when it changes, to avoid redrawing
the windows needlessly.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/850>

src/core/window-private.h

@@ -382,6 +382,9 @@ struct _MetaWindow
   /* TRUE iff window == window->display->focus_window */
   guint has_focus : 1;
 
+  /* TRUE if window appears focused at the moment */
+  guint appears_focused : 1;
+
   /* Have we placed this window? */
   guint placed : 1;
 
@@ -717,6 +720,8 @@ void        meta_window_get_session_geometry (MetaWindow  *window,
 
 void        meta_window_update_unfocused_button_grabs (MetaWindow *window);
 
+void        meta_window_update_appears_focused (MetaWindow *window);
+
 void     meta_window_set_focused_internal (MetaWindow *window,
                                            gboolean    focused);
 

src/core/window.c

@@ -251,6 +251,10 @@ prefs_changed_callback (MetaPreference pref,
       meta_window_recalc_features (window);
       meta_window_queue (window, META_QUEUE_MOVE_RESIZE);
     }
+  else if (pref == META_PREF_FOCUS_MODE)
+    {
+      meta_window_update_appears_focused (window);
+    }
 }
 
 static void
@@ -402,7 +406,7 @@ meta_window_get_property(GObject         *object,
       g_value_set_string (value, win->mutter_hints);
       break;
     case PROP_APPEARS_FOCUSED:
-      g_value_set_boolean (value, meta_window_appears_focused (win));
+      g_value_set_boolean (value, win->appears_focused);
       break;
     case PROP_WM_CLASS:
       g_value_set_string (value, win->res_class);
@@ -1514,7 +1518,7 @@ meta_window_unmanage (MetaWindow  *window,
    * on what gets focused, maintaining sloppy focus
    * invariants.
    */
-  if (meta_window_appears_focused (window))
+  if (window->appears_focused)
     meta_window_propagate_focus_appearance (window, FALSE);
   if (window->has_focus)
     {
@@ -4911,6 +4915,9 @@ set_workspace_state (MetaWindow    *window,
         }
     }
 
+  if (!window->constructing)
+    meta_window_update_appears_focused (window);
+
   /* queue a move_resize since changing workspaces may change
    * the relevant struts
    */
@@ -5266,9 +5273,26 @@ meta_window_change_workspace_by_index (MetaWindow *window,
     meta_window_change_workspace (window, workspace);
 }
 
-static void
+void
-meta_window_appears_focused_changed (MetaWindow *window)
+meta_window_update_appears_focused (MetaWindow *window)
 {
+  MetaWorkspaceManager *workspace_manager;
+  MetaWorkspace *workspace;
+  gboolean appears_focused;
+
+  workspace_manager = window->display->workspace_manager;
+  workspace = meta_window_get_workspace (window);
+
+  if (workspace && workspace != workspace_manager->active_workspace)
+    appears_focused = window == meta_workspace_get_default_focus_window (workspace);
+  else
+    appears_focused = window->has_focus || window->attached_focus_window;
+
+  if (window->appears_focused == appears_focused)
+    return;
+
+  window->appears_focused = appears_focused;
+
   set_net_wm_state (window);
   meta_window_frame_size_changed (window);
 
@@ -5348,7 +5372,7 @@ meta_window_propagate_focus_appearance (MetaWindow *window,
 
       if (child_focus_state_changed && !parent->has_focus)
         {
-          meta_window_appears_focused_changed (parent);
+          meta_window_update_appears_focused (parent);
         }
 
       child = parent;
@@ -5423,7 +5447,7 @@ meta_window_set_focused_internal (MetaWindow *window,
       g_signal_emit (window, window_signals[FOCUS], 0);
 
       if (!window->attached_focus_window)
-        meta_window_appears_focused_changed (window);
+        meta_window_update_appears_focused (window);
 
       meta_window_propagate_focus_appearance (window, TRUE);
     }
@@ -5436,7 +5460,7 @@ meta_window_set_focused_internal (MetaWindow *window,
       meta_window_propagate_focus_appearance (window, FALSE);
 
       if (!window->attached_focus_window)
-        meta_window_appears_focused_changed (window);
+        meta_window_update_appears_focused (window);
 
       /* Re-grab for click to focus and raise-on-click, if necessary */
       if (meta_prefs_get_focus_mode () == G_DESKTOP_FOCUS_MODE_CLICK ||
@@ -7361,7 +7385,7 @@ meta_window_get_frame (MetaWindow *window)
 gboolean
 meta_window_appears_focused (MetaWindow *window)
 {
-  return window->has_focus || (window->attached_focus_window != NULL);
+  return window->appears_focused;
 }
 
 gboolean
@@ -8099,7 +8123,7 @@ meta_window_set_transient_for (MetaWindow *window,
       return;
     }
 
-  if (meta_window_appears_focused (window) && window->transient_for != NULL)
+  if (window->appears_focused && window->transient_for != NULL)
     meta_window_propagate_focus_appearance (window, FALSE);
 
   /* may now be a dialog */
@@ -8155,7 +8179,7 @@ meta_window_set_transient_for (MetaWindow *window,
   if (!window->constructing && !window->override_redirect)
     meta_window_queue (window, META_QUEUE_MOVE_RESIZE | META_QUEUE_CALC_SHOWING);
 
-  if (meta_window_appears_focused (window) && window->transient_for != NULL)
+  if (window->appears_focused && window->transient_for != NULL)
     meta_window_propagate_focus_appearance (window, TRUE);
 }
 

src/core/workspace.c

@@ -365,15 +365,37 @@ meta_workspace_remove (MetaWorkspace *workspace)
    */
 }
 
+static void
+update_workspace_default_focus (MetaWorkspace *workspace,
+                                MetaWindow    *not_this_one)
+{
+  g_autoptr (GSList) windows = NULL;
+  GSList *l;
+
+  windows = meta_display_list_windows (workspace->display, META_LIST_DEFAULT);
+  for (l = windows; l; l = l->next)
+    {
+      MetaWindow *window = META_WINDOW (l->data);
+
+      if (meta_window_located_on_workspace (window, workspace) &&
+          window != not_this_one)
+        meta_window_update_appears_focused (window);
+    }
+}
+
 void
 meta_workspace_add_window (MetaWorkspace *workspace,
                            MetaWindow    *window)
 {
+  MetaWorkspaceManager *workspace_manager;
+
   g_return_if_fail (g_list_find (workspace->mru_list, window) == NULL);
 
   COGL_TRACE_BEGIN_SCOPED (MetaWorkspaceAddWindow,
                            "Workspace (add window)");
 
+  workspace_manager = workspace->display->workspace_manager;
+
   workspace->mru_list = g_list_prepend (workspace->mru_list, window);
 
   workspace->windows = g_list_prepend (workspace->windows, window);
@@ -386,6 +408,9 @@ meta_workspace_add_window (MetaWorkspace *workspace,
       meta_workspace_invalidate_work_area (workspace);
     }
 
+  if (workspace != workspace_manager->active_workspace)
+    update_workspace_default_focus (workspace, window);
+
   g_signal_emit (workspace, signals[WINDOW_ADDED], 0, window);
   g_object_notify_by_pspec (G_OBJECT (workspace), obj_props[PROP_N_WINDOWS]);
 }
@@ -394,6 +419,8 @@ void
 meta_workspace_remove_window (MetaWorkspace *workspace,
                               MetaWindow    *window)
 {
+  MetaWorkspaceManager *workspace_manager = workspace->display->workspace_manager;
+
   COGL_TRACE_BEGIN_SCOPED (MetaWorkspaceRemoveWindow,
                            "Workspace (remove window)");
 
@@ -410,6 +437,9 @@ meta_workspace_remove_window (MetaWorkspace *workspace,
       meta_workspace_invalidate_work_area (workspace);
     }
 
+  if (workspace != workspace_manager->active_workspace)
+    update_workspace_default_focus (workspace, window);
+
   g_signal_emit (workspace, signals[WINDOW_REMOVED], 0, window);
   g_object_notify (G_OBJECT (workspace), "n-windows");
 }
@@ -658,6 +688,7 @@ meta_workspace_activate_with_focus (MetaWorkspace *workspace,
   if (focus_this)
     {
       meta_window_activate (focus_this, timestamp);
+      update_workspace_default_focus (workspace, focus_this);
     }
   else if (move_window)
     {