(svn r20451) -Codechange: Add helper function Window::GetScrollbar() to get the Scrollbar belonging to a scrollbar widget.

src/window.cpp

@@ -130,6 +130,39 @@ void Scrollbar::SetCapacityFromWidget(Window *w, int widget, int padding)
 	}
 }
 
+/**
+ * Return the Scrollbar to a widget index.
+ * @param widnum Scrollbar widget index
+ * @return Scrollbar to the widget
+ */
+const Scrollbar *Window::GetScrollbar(uint widnum) const
+{
+	const NWidgetLeaf *wid = this->GetWidget<NWidgetLeaf>(widnum);
+	switch (wid->type) {
+		case WWT_HSCROLLBAR: return &this->hscroll;
+		case WWT_SCROLLBAR:  return &this->vscroll;
+		case WWT_SCROLL2BAR: return &this->vscroll2;
+		default: NOT_REACHED();
+	}
+}
+
+/**
+ * Return the Scrollbar to a widget index.
+ * @param widnum Scrollbar widget index
+ * @return Scrollbar to the widget
+ */
+Scrollbar *Window::GetScrollbar(uint widnum)
+{
+	NWidgetLeaf *wid = this->GetWidget<NWidgetLeaf>(widnum);
+	switch (wid->type) {
+		case WWT_HSCROLLBAR: return &this->hscroll;
+		case WWT_SCROLLBAR:  return &this->vscroll;
+		case WWT_SCROLL2BAR: return &this->vscroll2;
+		default: NOT_REACHED();
+	}
+}
+
+
 /**
  * Set the window that has the focus
  * @param w The window to set the focus on

src/window_gui.h

@@ -407,6 +407,8 @@ public:
 	template <class NWID>
 	inline NWID *GetWidget(uint widnum);
 
+	const Scrollbar *GetScrollbar(uint widnum) const;
+	Scrollbar *GetScrollbar(uint widnum);
 
 	void InitNested(const WindowDesc *desc, WindowNumber number = 0);
 	void CreateNestedTree(const WindowDesc *desc, bool fill_nested = true);