Allow ScrollBar params of a ScrollContainer to be modified in _ready()

Initializes the sizes of the ScrollContainer and its associated
ScrollBars in _ready() to allow scroll values to be set in GDScript
initially.

scene/gui/scroll_container.cpp

@@ -264,6 +264,67 @@ void ScrollContainer::_ensure_focused_visible(Control *p_control) {
 	}
 }
 
+void ScrollContainer::_update_dimensions() {
+	child_max_size = Size2(0, 0);
+	Size2 size = get_size();
+	Point2 ofs;
+
+	Ref<StyleBox> sb = get_theme_stylebox("bg");
+	size -= sb->get_minimum_size();
+	ofs += sb->get_offset();
+	bool rtl = is_layout_rtl();
+
+	if (h_scroll->is_visible_in_tree() && h_scroll->get_parent() == this) { //scrolls may have been moved out for reasons
+		size.y -= h_scroll->get_minimum_size().y;
+	}
+
+	if (v_scroll->is_visible_in_tree() && v_scroll->get_parent() == this) { //scrolls may have been moved out for reasons
+		size.x -= v_scroll->get_minimum_size().x;
+	}
+
+	for (int i = 0; i < get_child_count(); i++) {
+		Control *c = Object::cast_to<Control>(get_child(i));
+		if (!c) {
+			continue;
+		}
+		if (c->is_set_as_top_level()) {
+			continue;
+		}
+		if (c == h_scroll || c == v_scroll) {
+			continue;
+		}
+		Size2 minsize = c->get_combined_minimum_size();
+		child_max_size.x = MAX(child_max_size.x, minsize.x);
+		child_max_size.y = MAX(child_max_size.y, minsize.y);
+
+		Rect2 r = Rect2(-scroll, minsize);
+		if (!scroll_h || (!h_scroll->is_visible_in_tree() && c->get_h_size_flags() & SIZE_EXPAND)) {
+			r.position.x = 0;
+			if (c->get_h_size_flags() & SIZE_EXPAND) {
+				r.size.width = MAX(size.width, minsize.width);
+			} else {
+				r.size.width = minsize.width;
+			}
+		}
+		if (!scroll_v || (!v_scroll->is_visible_in_tree() && c->get_v_size_flags() & SIZE_EXPAND)) {
+			r.position.y = 0;
+			if (c->get_v_size_flags() & SIZE_EXPAND) {
+				r.size.height = MAX(size.height, minsize.height);
+			} else {
+				r.size.height = minsize.height;
+			}
+		}
+		r.position += ofs;
+		if (rtl && v_scroll->is_visible_in_tree() && v_scroll->get_parent() == this) {
+			r.position.x += v_scroll->get_minimum_size().x;
+		}
+		r.position = r.position.floor();
+		fit_child_in_rect(c, r);
+	}
+
+	update();
+}
+
 void ScrollContainer::_notification(int p_what) {
 	if (p_what == NOTIFICATION_ENTER_TREE || p_what == NOTIFICATION_THEME_CHANGED || p_what == NOTIFICATION_LAYOUT_DIRECTION_CHANGED || p_what == NOTIFICATION_TRANSLATION_CHANGED) {
 		_updating_scrollbars = true;
@@ -272,67 +333,11 @@ void ScrollContainer::_notification(int p_what) {
 
 	if (p_what == NOTIFICATION_READY) {
 		get_viewport()->connect("gui_focus_changed", callable_mp(this, &ScrollContainer::_ensure_focused_visible));
+		_update_dimensions();
 	}
 
 	if (p_what == NOTIFICATION_SORT_CHILDREN) {
-		child_max_size = Size2(0, 0);
+		_update_dimensions();
-		Size2 size = get_size();
-		Point2 ofs;
-
-		Ref<StyleBox> sb = get_theme_stylebox("bg");
-		size -= sb->get_minimum_size();
-		ofs += sb->get_offset();
-		bool rtl = is_layout_rtl();
-
-		if (h_scroll->is_visible_in_tree() && h_scroll->get_parent() == this) { //scrolls may have been moved out for reasons
-			size.y -= h_scroll->get_minimum_size().y;
-		}
-
-		if (v_scroll->is_visible_in_tree() && v_scroll->get_parent() == this) { //scrolls may have been moved out for reasons
-			size.x -= v_scroll->get_minimum_size().x;
-		}
-
-		for (int i = 0; i < get_child_count(); i++) {
-			Control *c = Object::cast_to<Control>(get_child(i));
-			if (!c) {
-				continue;
-			}
-			if (c->is_set_as_top_level()) {
-				continue;
-			}
-			if (c == h_scroll || c == v_scroll) {
-				continue;
-			}
-			Size2 minsize = c->get_combined_minimum_size();
-			child_max_size.x = MAX(child_max_size.x, minsize.x);
-			child_max_size.y = MAX(child_max_size.y, minsize.y);
-
-			Rect2 r = Rect2(-scroll, minsize);
-			if (!scroll_h || (!h_scroll->is_visible_in_tree() && c->get_h_size_flags() & SIZE_EXPAND)) {
-				r.position.x = 0;
-				if (c->get_h_size_flags() & SIZE_EXPAND) {
-					r.size.width = MAX(size.width, minsize.width);
-				} else {
-					r.size.width = minsize.width;
-				}
-			}
-			if (!scroll_v || (!v_scroll->is_visible_in_tree() && c->get_v_size_flags() & SIZE_EXPAND)) {
-				r.position.y = 0;
-				if (c->get_v_size_flags() & SIZE_EXPAND) {
-					r.size.height = MAX(size.height, minsize.height);
-				} else {
-					r.size.height = minsize.height;
-				}
-			}
-			r.position += ofs;
-			if (rtl && v_scroll->is_visible_in_tree() && v_scroll->get_parent() == this) {
-				r.position.x += v_scroll->get_minimum_size().x;
-			}
-			r.position = r.position.floor();
-			fit_child_in_rect(c, r);
-		}
-
-		update();
 	};
 
 	if (p_what == NOTIFICATION_DRAW) {

scene/gui/scroll_container.h

@@ -69,6 +69,7 @@ protected:
 	Size2 get_minimum_size() const override;
 
 	void _gui_input(const Ref<InputEvent> &p_gui_input);
+	void _update_dimensions();
 	void _notification(int p_what);
 
 	void _scroll_moved(float);