Displaying graphical objects

摘要

An object, such as a widget, in a graphical user interface comprises an instance of a widget class in which is defined properties and/or methods which control operation of the object; and an associated instance of a look object class in which is defined properties and/or methods which control the look of the object. Responsibility for displaying the widget is given to methods of the look object class. Therefore, the appearance of the widget is determined by the look object class. Object-oriented programming techniques can be used to provide a plurality of look object classes derived from a common base class. <IMAGE>