Option to shrink panel: fix taskbar sizing

src/taskbar/taskbar.c

@@ -47,6 +47,7 @@ TaskbarSortMethod taskbar_sort_method;
 Alignment taskbar_alignment;
 
 void taskbar_init_fonts();
+int taskbar_compute_desired_size(void *obj);
 
 // Removes the task with &win = key. The other args are ignored.
 void taskbar_remove_task(Window *win);
@@ -174,6 +175,7 @@ void init_taskbar_panel(void *p)
 	panel->g_taskbar.area.size_mode = LAYOUT_DYNAMIC;
 	panel->g_taskbar.area.alignment = taskbar_alignment;
 	panel->g_taskbar.area._resize = resize_taskbar;
+	panel->g_taskbar.area._compute_desired_size = taskbar_compute_desired_size;
 	panel->g_taskbar.area._is_under_mouse = full_width_area_is_under_mouse;
 	panel->g_taskbar.area.resize_needed = 1;
 	panel->g_taskbar.area.on_screen = TRUE;
@@ -419,6 +421,22 @@ void taskbar_refresh_tasklist()
 	XFree(win);
 }
 
+int taskbar_compute_desired_size(void *obj)
+{
+	Taskbar *taskbar = (Taskbar *)obj;
+	Panel *panel = (Panel *)taskbar->area.panel;
+
+	if (taskbar_mode == MULTI_DESKTOP && !taskbar_distribute_size && !hide_taskbar_if_empty) {
+		int result = 0;
+		for (int i = 0; i < panel->num_desktops; i++) {
+			 Taskbar *t = &panel->taskbar[i];
+			 result = MAX(result, container_compute_desired_size(&t->area));
+		}
+		return result;
+	}
+	return container_compute_desired_size(&taskbar->area);
+}
+
 gboolean resize_taskbar(void *obj)
 {
 	Taskbar *taskbar = (Taskbar *)obj;

src/util/area.c

@@ -224,6 +224,13 @@ int compute_desired_size(Area *a)
 		return a->_compute_desired_size(a);
 	if (a->size_mode == LAYOUT_FIXED)
 		fprintf(stderr, YELLOW "Area %s does not set desired size!" RESET "\n", a->name);
+	return container_compute_desired_size(a);
+}
+
+int container_compute_desired_size(Area *a)
+{
+	if (!a->on_screen)
+		return 0;
 	int result = 2 * a->paddingxlr + (panel_horizontal ? left_right_border_width(a) : top_bottom_border_width(a));
 	int children_count = 0;
 	for (GList *l = a->children; l != NULL; l = l->next) {

src/util/area.h

@@ -260,6 +260,7 @@ void relayout(Area *a);
 int relayout_with_constraint(Area *a, int maximum_size);
 
 int compute_desired_size(Area *a);
+int container_compute_desired_size(Area *a);
 
 int left_border_width(Area *a);
 int right_border_width(Area *a);