1. A method of processing graphic data, the method comprising: reading data from an information storage medium, the data comprising a display set comprising an object segment and a composition segment, the object segment comprising graphic object data defining a graphic object to be used in composing a graphic screen to be displayed on a display device, and the composition segment comprising composition information for the graphic object defined by the graphic object data to be used in composing the graphic screen, the composition information specifying how the graphic object is to be displayed on the graphic screen; storing the graphic object data for a predetermined time so that the graphic object data remains available for use for the predetermined time; storing the composition information; and outputting the graphic object data according to the composition information.