Drawing on the Screen
System software routines, such as the routines provided by QuickDraw, perform all drawing on the screen. For example, your application tells QuickDraw what and where to draw, and QuickDraw does the actual drawing to the screen. The graphics routines provided by system software support quick drawing of objects such as circles, ovals, rectangles, lines, text, and pictures. See Inside Macintosh: Imaging for specific graphics- related information.