What computer graphics is
Computer graphics deals with generating images, and art, with the aid of computers. It is a core technology in digital photography, film, video games, digital art, and in the displays of phones and computers, along with a long list of specialised applications. A great deal of hardware and software exists for nothing else. The display on most devices is driven by graphics hardware, whether or not the owner ever thinks of it that way. As a field it is large, and it is recent. It sits inside computer science. The non-artistic part of the work, the part about algorithms and machines rather than about pictures someone wants to look at, is a research subject in its own right.
The phrase was put into circulation around 1960 by William Fetter, a graphic designer at Boeing, who credited his colleague Verne Hudson. Some accounts date the wording to 1961. Either way it is a Boeing phrase from that moment, not a later marketing coinage. It is often shortened to CG. In film the usual shortening is CGI, computer-generated imagery. The two abbreviations are not quite synonyms. CG is the field. CGI is what a film credit means when it says the picture was built rather than photographed, though a modern shot is often both.
Three things the phrase points at
People use "computer graphics" for almost everything on a computer that is not text or sound. That wide sense is real, and it is too wide to work with. In practice the term points at three related things:
- the representation and manipulation of image data by a computer
- the technologies used to create and manipulate images
- methods for digitally synthesising and manipulating visual content
The third of those is the study itself. The first is what a file contains. The second is the machinery, from a graphics chip to a program that paints a texture onto a polygon. A conversation that slides between the three without saying so gets confusing fast. A graphics chip is not a picture. A picture is not a method. The method is what turns the one into the other.
Where the pictures are
Today the imagery is ordinary. It is on television, in newspapers, in a weather report, and in medical investigations and surgical procedures. A well-constructed graph can present a complicated statistic in a form that is easier to interpret than the table it came from. In print, graphs of that kind illustrate papers, reports, and theses. A computer is now the usual way of drawing it.
Many tools exist for visualising data. Computer-generated imagery is commonly split into two-dimensional, three-dimensional, and animated graphics. As the machines improved, 3D became more common. 2D did not go away, and for a lot of work it is still the right tool, because a flat design wants direct control of the marks. A solid model is a different job.
Over the last decades, neighbouring fields have split off. Information visualisation is one. Scientific visualisation is another, more concerned with three-dimensional phenomena, architectural, meteorological, medical, biological, and the like, where the emphasis is on a convincing rendering of volumes, surfaces, and lights, sometimes with time in the picture as well. The family resemblance is obvious. The daily work is not the same. A chart of sales and a rendering of a storm are both "graphics" only at the altitude where the word stops helping.
What the study actually studies
As an academic subject, computer graphics studies the manipulation of visual and geometric information using computational techniques. It focuses on the mathematical and computational foundations of image generation and processing, rather than on taste. It is often set apart from visualisation, though the two share a great deal. A student in the subject is more likely to meet a rendering equation than a discussion of a typeface. Both can be on the same screen by the end of the day.
The list of applications is long enough to be dull if it is only a list, and useful if you notice how far it spreads: augmented and extended reality, computational photography, computer-aided design, digital art, education, infographics, motion graphics, simulation, special effects, video games, and pictures delivered in a web page. Design, in the older sense, is on that list and not swallowed by it. A poster made by hand and a poster laid out on a machine are still posters. The machine changed the speed and the kind of mistake, not the fact that someone has to decide what the poster is for.