UBC Theses and Dissertations
A graphical extension for Pascal based on the Graphical Kernel System Starr, Cynthia Louise
The Graphical Kernel System (GKS), the first international standard in the area of computer graphics, was adopted by the International Standards Organization in 1985. The United Kingdom, France, Germany and the United States have also adopted GKS as a national standard. This thesis examines the feasibility of developing a high-level graphical extension to a general-purpose programming language based on the GKS standard. Because GKS was designed as a subroutine system, programming with it is awkward. The subroutine call provides a low-level mechanism for accessing the graphical capabilities standardized by GKS. EZ/GKS is a high-level graphical extension to the Pascal/VS language implementing the functionality found in GKS level 2A. The level of abstraction for graphics programming is elevated in EZ/GKS through the use of abstract graphical data types. Operations on graphical data types are provided by structured graphical assignments, high-level graphical statements, graphical expressions and system-defined functions. Complex user-defined data types may be constructed from any of the predefined graphical data types in the usual manner provided by Pascal. No major syntactic or semantic difficulties were encountered during the design and implementation of EZ/GKS. Thus, it appears that the GKS standard can indeed be elevated successfully to a high-level graphical extension of a general-purpose programming language.
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