The basic principle of PHIGS is to create graphic structures, and to store them in a tree data base called CSS, where they may be subsequently edited and modified. Once the CSS is built, simply specify the list of structures to be displayed on a workstation (post structures) and request a workstation update (redraw structures). It is possible to save all or part of the CSS on the disk, so as to be able to retrieve it in an application. This makes it possible, for example, to build structure libraries.
A PHIGS application may or may not have "input", i.e. interactions with the user.
This input may be :
CHOICE : a choice from "n" integers
PICK : Pick a primitive
LOCATOR : x, y, (z) coordinates
STRING : Character string
VALUATOR : Real
The input operating mode may be :
REQUEST (default) : user validation locking standby
SAMPLE : no user validation standby
EVENT : event file management
GPHIGS manages all this input via Phigs Input Manager (PIM).
See GPHIGS USER GUIDE for further details.