Book Reviews

F.R.A.Hopgood, D.A.Duce, J.R.Gallop, D.'Csutcliffe Introduction to the Graphical Kernel System (GKS)
G.Enderle, K.Kansy, G.Pfaff Computer Graphics Programming.
Reviewer: Ken Brodlie Department of Computer Studies University of Leeds     

Book Reviews

Book reviewed in this article:
Introduction to the Graphical Kernel System (GKS), F.R.A.
Elementary Computer Graphics, A.A.
SMALLTALK 80: Bits of History, Words of Advice Edited by Glen Krasner, Xerox PARC.     

3D extension to GKS

The Graphical Kernel System GKS has [1] been established as the first standard in the field of Computer Graphics covering two-dimensional (2D) graphics. Now work is going on to develop standards in related areas. One important effort is the extension of GKS for three-dimensional (3D) graphics. This paper will briefly overview the history of standardization efforts with respect to 3D graphics and then report the current activities of various national and international standardization bodies for extending GKS to 3D. Then the paper will concentrate on GKS-3D [2], a proposal for a 3D extension of GKS which is developed by the Dutch standardization committee NNI in close collaboration with the International Organization for Standardization ISO/TC97/SC21/WG2. Technical work is expected to finish in 1985. Scope and purpose of this future 3D standard and goals of the design are given and the functionality of the 3D extension is described in some detail. As technical work on GKS-3D is going on, changes may occur to the standard document. The major issues will be surveyed and trends will be sketched.     

Formal Specification in the Revision of GKS: An Illustrative Example

The first ISO/IEC standard for computer graphics, the Graphical Kernel System (GKS) was published in August 1985. In accordance with ISO/IEC procedures, GKS is now being reviewed and revised. This paper describes how formal specification techniques are being used by the authors to analyse key parts of proposals being made for changes to the framework of GKS to bring the standard into line with the requirements of applications and the operating environment likely to be found in the mid-1990's.     

GKS-9x: Some Implementation Considerations

The Graphical Kernel System (GKS) was published as an ISO standard for computer graphics programming in August 1985. GKS is now undergoing revision in ISO/IEC and at the time of writing the text of the Draft International Standard of GKS-9x was being finalized. This paper presents a way in which a key part of the new functionality in GKS-9x, namely namesets and selection criteria, can be implemented effectively.     

Standardization of the virtual device metafile and the virtual device interface

The American National Standards Institute (ANSI) is developing several graphics standards. Two of these standards, the Virtual Device Metafile and the Virtual Device Interface, are reviewed. The purpose, basic concepts and philosophy of these standards are discussed and contrasted with current practice and the Graphical Kernel System standard. The virtual device metafile is in the final stages of standardization within ANSI and is being reviewed within the International Standards Organization (ISO) for adoption as an international standard. The virtual device interface standard is currently under development within ANSI.     

On developing a GKS driver architecture for raster workstations

The use of raster graphics devices needs adapting to graphics applications. The first graphics standard, the Graphics Kernel System GKS, defines a logical interface on an application and device independent level. The workstation driver maps the logical GKS functions to device functions. First some special raster device facilities are outlined and then it is shown how to use them within the driver. To reduce the amount of driver implementations a common driver concept is sought here, especially for raster devices.     

The evolution of standards for computer graphics

Although work towards international standards for computer graphics was started in 1976, it is in the last 2 years that real agreement and progress have been achieved. The first target, the functional specification of a graphics system, is satisfied by the graphical kernel system (GKS), which is now being processed as an International Organization for Standardization (ISO) draft international standard. GKS provides a reference model for two-dimensional graphics and an agreed vocabulary of terms covering the field. Many implementations of GKS as a package are now being produced. In addition to such a functional specification, two forms of communication are appropriate for graphics: a metafile and a virtual device interface. ISO is now reviewing a proposal for a metafile standard developed by the American National Standards Institute and closely related to GKS. Standards for a graphics virtual device interface and for three-dimensional graphics systems are also being actively developed. All these efforts and their interrelationships are described and examined.     

GKS-94: an overview

A revision of the Graphical Kernel System (GKS), the first ISO standard for computer graphics programming, was completed in 1994. This summary of GKS-94 also describes an implementation of part of its new functionality. We have demonstrated that fast selection is possible with GKS-94. Thus, an application can use namesets and selection criteria as its main method of subdivision, selection and creating hierarchy within the application, and performance is acceptable given a reasonable implementation. European organizations are showing interest in implementing GKS-94, and new products are anticipated early in 1996     

Graphics standards in the GDR

This article outlines implementations and applications of the GKS standard and GKS-3D standard in the German Democratic Republic (GDR). The graphical standardization in the GDR was highly stimulated by becoming a member of the ISO and by the active colaboration of the GDR in the ISO/IEC JTC1/SC24 “Computer Graphics.” Some of the national activities and efforts in this field are illustrated.     

GRAPH—An interactive program based on the Graphical Kernel System

This paper describes a program which provides an interactive command driven interface to the Graphical Kernel System (GKS).     

A verifier for checking the conformance of programs with the GKS standard

A software development tool is introduced which allows to check the corrections of programs using the Graphical Kernel System (GKS). Such graphical application programs are checked whether their use of GKS functions is syntactically correct and conforms with semantic rules given by the GKS definition. Like the PFORT verifier for FORTRAN programs, this tool greatly reduces development time for GKS programs.     

ADA† and NIL: Two Concurrent Languages for GKS

The Graphical Kernel System (GKS) has become an international standard in graphics programming and attempts are now being made to integrate it with multiprocessing, possibly in distributed systems. It is therefore necessary to consider new programming languages able to support distributed implementations of GKS. Among them, Ada and Nil are considered here, since they are particularly suitable for concurrent programming. They are compared and evaluated in those specific tools which may provide data safety, system reconfigurability, and availability to distributed programming. The structural philosophies of the two languages are emphasized and reconfigurable implementation schemata for GKS in both of them are then suggested.     

A Proposal for a Distributed Model of GKS Based on Prolog

The Graphical Kernel System GKS is so well established as a standard for graphics programming that quite a number of models for multiprocessor and distributed environments have already been suggested. It is therefore necessary to consider new languages and methodologies capable of supporting its distributed implementation. In this context, clausal logic languages provide suitable means for describing the system in a declarative form and, moreover, ensure the applicability of meta-programming techniques for specifying the semantics of implementation. The Prolog language, extended with communication and modularization structures required by the distributed programming, is thus here considered as a feasible means for establishing a model of GKS organized in functional modules which could be supported by different processors. For such a model a two-level implementation scheme is outlined and a reconfiguration and personalization methodology is suggested.     

Better Understanding through Formal Specification

The Graphical Kernel System (GKS) is now registered as an ISO International Standard for computer graphics programming. One of the major innovations of the Standard is the bundled specification of aspects, a mechanism which gives the applications programmer the ability to tailor the appearance of a picture independently on each of the workstations on which it is displayed, using the capabilities of the workstations. GKS also incorporates the traditional method of individual specification of aspects in which each workstation does the best it can to represent global aspect values. In this paper a formal specification technique, the Vienna Development Method (VDM), is used to describe aspect specification. The GKS model of aspect specification is progressively constructed from simpler models. Properties of these simpler models are formulated and the specifications are proved to conform to these. The properties are then traced through the more complex models. The paper demonstrates the applicability of formal specification to the design of graphics software and the ability of formal techniques to catalyse the deeper understanding of designs.     

Logical Input Devices and Interaction

The logical input device model, as is adopted in the standardized graphics package GKS, has been an accepted basis for producing device-independent graphics systems. However, when used in highly interactive graphical applications, the logical input device model does not provide sufficient support for a number of fundamental issues inherent to interaction. This paper reopens a discussion which questions the functionality provided by the logical input device model when brought in conjunction with interaction. In particular, the logical input device model does not support the notion of input/output symmetry. CR Categories: 1.3.4 [Computer graphics]: Graphics utilities- graphics packages; 1.3.6 [Computer graphics]: Methodology and techniques- device independence, interaction techniques     

A VLSI Implementation of the Graphics Standard GKS

The main advantage when using a standardized graphics system is quite obvious: the application programs become portable. Integrating such a system - and GKS (Graphical Kernel System) is the only one being standardized internationally - into VLSI (Very Large Scale Integration) chips, this graphics system may become an integral part of graphical devices. This guarantees a uniform interface of such devices to GKS applications. Devices of many different kinds will become compatible not only with respect to plugging but even in their logical behaviour, eliminating all device dependencies from the host software.
We have started to design the GKS-chip which will be able to be used in a great variety of devices (vector and raster type). The GKS-chip will bring the computational power to support real time picture updates, limited only by the maximally attainable output data rate.     

GKS in Pascal

The design of the Pascal interface to the Graphics Kernel System is discussed and illustrated. The principles underlying the binding are given and examples show how some of the major features of GKS will look in Pascal. The examples cover graphical output, setting primitive representation, graphical input and inquiries.