An object-oriented class library for the creation of engineering graphs

Since the availability of the first PHIGS (Programmers Hierarchical Interactive Graphics System) implementation in the mid 1980’s, interest in the use of PHIGS has been steadily growing among the CAD applications developer’s community. Every year, more PHIGS-based CAD applications programs are being created to ensure portability and make use of the high-level support provided by PHIGS [JAYA93b].

One of the common uses of computer graphics in engineering is for the creation of graphs. Commonly used graphs, such as line graphs (two-dimensional or three-dimensional), bar charts, pie charts, surface plots, etc., can be created using PHIGS. This involves the creation of several methods to scale the data, draw the graph, display labels, display axes, display legends and several other programming tasks, which are re-created by each applications program.

This thesis describes the creation of an object-oriented class library to facilitate the creation of engineering graphs using PHIGS. This library provides the programmer with a set of tools to create commonly used graphs (line graphs, pie charts, bar charts, polar plots, and 3D plots). The class library will allow PHIGS programmers to quickly and easily create graphs for use with applications programs. This set of classes uses a PHIGS-based, Motif-like interface framework (described by Woyak and Myklebust [WOYA93]). User interface methods to allow the end-user of the graphing program to modify attributes of the graph (e.g. line types, legends, colors, etc.) are encapsulated within this class library and are hidden from the programmer using these classes. The library of classes, the user interface methods, and the use of this system is described in this thesis.