Introduction to Computer Graphics.

Copyright (c) Susan Laflin. August 1999.

Computer Graphics has come a long way since early days in the 1960s. Many software packages have been written and much work done on standards in graphics. Students should note that "de-facto standards" produced by different manufacturers differ from those accepted by ISO (the International Standards Organisation). ISO standards have been widely discussed before they are adopted, detailed definitions are widely available and there is usually some arrangement for validation of software which claims to implement the standard. "De-facto standards" are produced by some manufacturer with ambitious ideas, the amount of information is usually very much less (some of the details are often commercial secrets) and there is no guarantee that the next version will be compatible with the previous one, nor is it easy for other manufacturers to compete in producing software for this "standard". The lack of information makes validation impossible.

Computer graphics practitioners have to be masters of illusion. Faced with a blank screen and some means of illuminating different pixels in different colours, they must find ways of representing their ideas, in terms of these coloured dots, so that others may look at the same screen and understand the concepts illustrated. Thus it has to be both an art and a science.

Opinions about the scope of the subject vary greatly. Some take the view that all computer output is either text or graphics and thus include all non-text output. This gives a very large subject area. Others remove all applications using graphics to the application area, for example graphical techniques to visualise problems in physics are counted as part of physics not computer graphics. Then they remove aspects of hardware and computer systems; pattern recognition and image processing are defined a separate subjects; and eventually little more than the upkeep of standards and software packages is left. There is even some talk of defining visualisation as a separate area.

My opinion is that this second approach is far too restrictive. Computer graphics should include input of graphical information and this means there must be considerable overlap between graphics and image processing. It will certainly include the output of all types of graphical information and this must include visualisation techniques. Since the same techniques may be used in many different application areas it is essential to have some subject which includes an overall view of these methods, otherwise there will be too much duplication of effort. I consider that computer graphics fulfils this role. Obviously standards are very important for the transfer of software and pictures from one person or installation to another, but this is only a small part of computer graphics.

History of Computer Graphics

This section gives an historical introduction, showing how the subject has developed since 1960. The references mentioned in this text are repeated here.

References:-

Computer Graphics Volume 10 No 3 Fall 1976. (This contains a report of the Seillac Workshop).

Computer Graphics Volume 11 No 3 Fall 1977. Status Report of G.S.P.C. of ACM/SIGGRAPH.
Part 1 State of the Art of Graphics Software Packages.
Part 2 General Methodology and the Proposed Standard.

Computer Graphics Volume 12 Nos 1-2 June 1978. Final Report of G.S.P.G. State of the Art Subcommittee.

Computer Graphics Volume 13 No 3 August 1979. Status Report of G.S.P.C. including Raster Extensions.

Computer Graphics Volumes 14 onwards No 3. Every August, the papers from the annual SIGGRAPH conference appear in this number of Computer Graphics.

Computer Graphics Forum. This is the journal of Eurographics and contains many useful papers. It first appeared in 1982.

EUROGRAPHICS 1980 onwards. The Eurographics conference proceedings are published annually.

Graphics Standards.

This section discusses the various graphics standards developed, mainly in the 1980s.

The Graphical Kernel System.

This section gives a brief introduction to one standard, G.K.S. The references describing this standard are given below.

Introduction to the Graphical Kernel System. Hopgood et al. Academic Press. 2nd Edition 1986.

Computer Graphics Programming - GKS The Graphics Standard. Enderle et al. Springer Verlag. 1984 98DM

Computer Graphics: SIGGRAPH. a special issue on GKS published February 1984.

CGM and CGI. Arnold and Bono. Springer Verlag. 1988.

CGM in the Real World. ed Mumford and Skall. Springer Verlag 1988.