void        ScrollView(const Rect& r, int dx, int dy);
	void        ScrollView(int x, int y, int cx, int cy, int dx, int dy);
	void        ScrollView(int dx, int dy);
	void        ScrollView(const Rect& r, Size delta)    { ScrollView(r, delta.cx, delta.cy); }
	void        ScrollView(Size delta)                   { ScrollView(delta.cx, delta.cy); }