__ The Graphical Kernel System.__

Copyright (c) Susan Laflin. August 1999.

The Graphical Kernel System (GKS) is accepted as an international standard for two-dimensional graphics (although largely ignored in the USA). It was accepted as such in 1984 and was followed by other related standards, namely:-

CGI - the computer graphics interface - which is the low-level interface between GKS and the hardware.

CGM - the computer graphics metafile - which is defined as the means of communicating between different software packages.

3D-GKS - the three-dimensional extension of GKS.

PHIGS - the Programmers Hierarchical Interactive Graphics System - another three-dimensional standard (based on the old SIGGRAPH core).

The following texts are useful for anyone wishing to become familar with GKS.

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.

The section on two-dimensional Computer Graphics is closely related to the six output functions of GKS. These are:-

1. Polyline. Draws one or more straight lines through the coordinates supplied.

2. Polymarker. Draws a symbol at each of the coordinates supplied. The software allows the choice of one of the five symmetric symbols, namely: x + * 0 and .

3. Text. This allows a text string to be output in a number of ways, starting at the coordinate given.

4. Fill-area. This allows a polygon to be drawn and filled, using the coordinates given. Possible types of fill include hollow, solid and a variety of hatching and patterns.

5. Cell-array. This allows a pattern to be defined and output in the rectangle defined by the coordinates given. This is discussed in the section "Patterns & Pictures".

6. Generalised Drawing Primitive (GDP). This allows the provision of a variety of other facilities. Most systems include software for arcs of circles or ellipses and the drawing of a smooth curve through a set of points (I have called this "polysmooth" elsewhere in this text).

For the other facilites offered by GKS, you are recommended to look at one or other of the texts referred to above.