Computer Graphics
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 development of various microcomputer graphics software, particularly that from Lotus Development Corporation in 1982, has been gladly hailed by the business community. Graphics software converts numerical data into high resolution bar, pie or line graphs, giving greater impact to business documents, reports and presentations. Draw and paint programs, another type of graphics software, first appeared in the mid-to late 1980s.
Such programs, called interactive software, are used by designers, artists and engineers to create or modify illustrations directly on screen. Specialized CAD/CAM software is also available, however, it often requires powerful computer workstations to operate to its greatest potential. Although graphic screens can generate high quality drawings, they cannot produce hard copy output. The graphic plotter, first conceived in 1833 by Charles Babbage for his analytical engine, is most useful for this purpose. Plotters produce high resolution three-dimensional output on single sheets or continuous rolls of paper. Capable of large, intricate drawings of exacting precision, plotters utilize computer-controlled pens positionable at up to 45,000 different points in each square inch. One type of plotter, the drum plotter, uses a continuous roll of paper that moves forward and backward over a drum. A number of pens suspended over the paper move from side to side and are raised or lowered to make contact with the paper. Drum plotters are often used as the output device on CAD/CAM stations to produce immense drawings of electronic circuitry. Commonly used by the business community, the flatbed plotter looks much like a drafting table, with various colored pens held in place by a frame. Although flatbed plotters are limited to using single sheets of paper, they are much less expensive than drum plotters, which may cost upwards of $250,000.
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