Add behavior to hide an empty taskbar in multi_desktop mode

src/panel.c

@@ -269,12 +269,11 @@ void init_panel()
 
 		if (panel_autohide)
 			autohide_trigger_hide(p);
-
-		update_taskbar_visibility(p);
 	}
 
 	taskbar_refresh_tasklist();
 	reset_active_task();
+	update_all_taskbars_visibility();
 }
 
 void init_panel_size_and_position(Panel *panel)

src/taskbar/taskbar.c

@@ -430,18 +430,46 @@ gboolean resize_taskbar(void *obj)
 	return FALSE;
 }
 
+void update_one_taskbar_visibility(Taskbar *taskbar)
+{
+	//TODO handle hidden name
+	gboolean taskbar_non_empty = g_list_length(taskbar->area.children) > 1;
+
+	if (taskbar->desktop == server.desktop) {
+		// Taskbar for current desktop is always shown
+		taskbar->area.on_screen = TRUE;
+	}
+	else if (taskbar_mode == MULTI_DESKTOP && taskbar_non_empty) {
+		// MULTI_DESKTOP : show non-empty taskbars
+		taskbar->area.on_screen = TRUE;
+	}
+	else {
+		taskbar->area.on_screen = FALSE;
+	}
+
+	panel_refresh = TRUE;
+}
+
+void update_all_taskbars_visibility()
+{
+	for (int i = 0; i < num_panels; i++) {
+		Panel *panel = &panels[i];
+		for (int j = 0; j < panel->num_desktops; j++) {
+			update_one_taskbar_visibility(&panel->taskbar[j]);
+		}
+	}
+	panel_refresh = TRUE;
+}
+
 void set_taskbar_state(Taskbar *taskbar, TaskbarState state)
 {
 	taskbar->area.bg = panels[0].g_taskbar.background[state];
 	if (taskbarname_enabled) {
 		taskbar->bar_name.area.bg = panels[0].g_taskbar.background_name[state];
 	}
-	if (taskbar_mode != MULTI_DESKTOP) {
+
-		if (state == TASKBAR_NORMAL)
+	update_one_taskbar_visibility(taskbar);
-			taskbar->area.on_screen = FALSE;
+
-		else
-			taskbar->area.on_screen = TRUE;
-	}
 	if (taskbar->area.on_screen) {
 		schedule_redraw(&taskbar->area);
 		if (taskbarname_enabled) {
@@ -459,22 +487,6 @@ void set_taskbar_state(Taskbar *taskbar, TaskbarState state)
 	panel_refresh = TRUE;
 }
 
-void update_taskbar_visibility(void *p)
-{
-	Panel *panel = (Panel *)p;
-
-	for (int j = 0; j < panel->num_desktops; j++) {
-		Taskbar *taskbar = &panel->taskbar[j];
-		if (taskbar_mode != MULTI_DESKTOP && taskbar->desktop != server.desktop) {
-			// SINGLE_DESKTOP and not current desktop
-			taskbar->area.on_screen = FALSE;
-		} else {
-			taskbar->area.on_screen = TRUE;
-		}
-	}
-	panel_refresh = TRUE;
-}
-
 #define NONTRIVIAL 2
 gint compare_tasks_trivial(Task *a, Task *b, Taskbar *taskbar)
 {

src/taskbar/taskbar.h

@@ -79,10 +79,11 @@ Task *get_task(Window win);
 // However for windows shown on all desktops, there are multiple buttons, one for each taskbar.
 GPtrArray *get_task_buttons(Window win);
 
+// Change state of a taskbar (ACTIVE or NORMAL)
 void set_taskbar_state(Taskbar *taskbar, TaskbarState state);
 
-// Updates the visibility of each taskbar when the current desktop changes.
+// Updates the visibility of all taskbars
-void update_taskbar_visibility(void *p);
+void update_all_taskbars_visibility();
 
 // Sorts the taskbar(s) on which the window is present.
 void sort_taskbar_for_win(Window win);

src/tint.c

@@ -1010,7 +1010,7 @@ void event_property_notify(XEvent *e)
 			int old_desktop = server.desktop;
 			server_get_number_of_desktops();
 			server.desktop = get_current_desktop();
-			if (old_num_desktops != server.num_desktops) {
+			if (old_num_desktops != server.num_desktops) { // If number of desktop changed
 				if (server.num_desktops <= server.desktop) {
 					server.desktop = server.num_desktops - 1;
 				}
@@ -1019,11 +1019,11 @@ void event_property_notify(XEvent *e)
 				for (int i = 0; i < num_panels; i++) {
 					init_taskbar_panel(&panels[i]);
 					set_panel_items_order(&panels[i]);
-					update_taskbar_visibility(&panels[i]);
 					panels[i].area.resize_needed = 1;
 				}
 				taskbar_refresh_tasklist();
 				reset_active_task();
+				update_all_taskbars_visibility();
 				panel_refresh = TRUE;
 			} else if (old_desktop != server.desktop) {
 				for (int i = 0; i < num_panels; i++) {
@@ -1092,6 +1092,7 @@ void event_property_notify(XEvent *e)
 			if (debug)
 				fprintf(stderr, "%s %d: win = root, atom = _NET_CLIENT_LIST\n", __FUNCTION__, __LINE__);
 			taskbar_refresh_tasklist();
+			update_all_taskbars_visibility();
 			panel_refresh = TRUE;
 		}
 		// Change active