Interfaces to Graphics Devices

Abstract

GKS is based on the concept of abstract workstations. A GKS workstation represents a unit consisting of zero or one display surfaces and zero or more input devices, such as a keyboard, tablet and/or lightpen. The workstation presents these devices to the application program as a configuration of abstract devices, thereby abstracting from the hardware peculiarities. Workstations provide the logical interface through which the application program controls physical devices. Certain special workstations provide facilities for the storage and exchange of graphical information. In Table 4.3 in Chapter III.4.4 on page 133, all GKS functions are listed, together with the workstation categories to which they directly or indirectly apply. Output, attribute, transformation and segment functions, for example, apply to all output, output/input, and metafile output workstations, whereas they do not apply to input and metafile input workstations.