Computer graphics is a pictorial communication between humans and computers. While almost any problem and solution can be reduced to alphanumeric form, it is often an unnatural and time-consuming way to think and work. Introduced in the 1970s, graphic screen displays and plotters bridge the gap between computers and humans, allowing for creation and output of any form imaginable. Graphic screen displays differ from alphanumeric displays, as they are capable of showing the usual letters, numbers and symbols plus graphs, diagrams, lines, curves, circles and other shapes. Input can be accomplished using a keyboard, but other input devices--such as a light pen, mouse, track ball, or digitizer--are frequently used to speed up the process. Such input devices used on a graphic workstation are an essential part of CAD/CAM (computer-aided design and manufacturing) applications, enabling complex drawings to be created or changed at will on-screen. The...