Graphical Kernel System

Abstract: This highly acclaimed "Introduction to the Graphical Kernel System (GKS)" has now been revised and updated following the publication of the "International Standard (ISO 7942)" in August 1985 and the draft international standard (ISO 8651) for the FORTRAN, Pascal, and Ada GKS language bindings. The main aim of this book is to provide an introduction to the concepts of GKS and the FORTRAN language binding. A basic knowledge of computer graphics is assumed. The first part of the text covers the background and major ideas of the system, and the second covers those features more likely to be required by the specialist graphics programmer. Appendices and an index allow the work to be used as a reference manual. All application programmers with an interest in computer graphics will find this book an invaluable aid.

Abstract: I. Introduction to Computer Graphics (Part I).- 1. Acknowledgement.- 2. General Introduction.- 3. Digitising.- 3.1 Manual Digitisers.- 3.2 Semi-Automatic Digitisers.- 3.3 Scanners and TV Cameras.- 4. Graphical Displays.- 4.1 Direct View Storage Tube Display (DVST).- 4.2 Refresh Displays.- 4.3 Raster Displays.- 4.4 Display System Architectures and More Advanced Features.- 4.5 Bit-Mapped Raster Displays.- 5. Input Tools.- 6. Hard Copy Devices.- 6.1 Flat-Bed Plotter.- 6.2 Drum Plotter.- 6.3 Electrostatic Plotter.- 6.4 Matrix Printer.- 6.5 Ink-Jet Plotter.- 6.6 Camera.- 6.7 Camera-Systems.- 6.8 Computer Output on Microfilm (COM).- 6.9 Recommended Reading.- II. Introduction to Computer Graphics (Part II).- 1. Projections and Viewing.- 1.1 Planar Geometric Transformations.- 1.2 Specifying Projections in a Graphics System.- 1.3 Clipping in 3-D.- 1.4 Representing Solid Objects.- 1.5 Half-Toning Techniques.- 2. Colour.- Recommended Reading and References.- III. Introduction to Computer Graphics (Part III).- 1. Graphics Concepts.- 1.1 Graphics Software Overview.- 1.2 Device Independent Graphics Standards.- 1.3 Graphical Output.- 1.4 Graphics-Based Input.- 1.5 Human Factors in Interactive Programming.- 1.6 Interaction Techniques.- 2. Modelling Concepts.- 2.1 Object Definition.- 2.2 Two-Dimensional Transformations.- 2.3 Three-Dimensional Transformations.- References.- IV. Interactive Techniques.- 1. Introduction.- 2. User Interface.- 3. Interaction and Graphics.- 4. Dialogues.- 4.1 The Separation of Algorithm and Dialogue.- 4.2 Dialogue Cells.- 4.3 The Basic Cycle of a Dialogue Cell.- 4.4 Input Parsing.- 4.5 The Input Pool.- 5. The Interface to the Graphics System.- 5.1 A Symmetric I/O Layer on Top of GKS.- Appendix A: Complete Syntax for Dialogue Cells.- Appendix B: Examples for Dialogue Cells.- V. Specification Tools and Implementation Techniques.- 1. Introduction.- 1.1 Overview.- 1.2 Notions.- 2. Models and Design Strategy.- 2.1 Models.- 2.2 Design Strategy.- 3. Guidelines and Observations.- 3.1 Theoretical Aspects.- 3.2 Practical Aspects.- 3.3 Problems Arising.- 4. Tools and Techniques.- 4.1 System Model.- 4.2 Describing a Dialogue System.- 4.3 Dialogue Cells.- 5. Conclusion.- 6. Literature.- VI. The Graphical Kernel System.- 1. Introduction.- 2. GKS Overview.- 3. Concepts and Programming of GKS.- 3.1 Graphical Output.- 3.2 Workstation Concepts.- 3.3 Coordinate Systems and Transformations.- 3.4 Segment Concept.- 3.5 Graphical Input.- 3.6 GKS Metafile Interface.- 3.7 GKS Level Structure.- 3.8 State of GKS.- 3.9 Error Handling.- 3.10 Special Interfaces.- 4. GKS Interfaces.- 4.1 Language Interfaces.- 5. Acknowledgement.- 6. References.- Annex 1: GKS FORTRAN SUBROUTINE names.- Annex 2: Correspondence of GKS data types and FORTRAN data types.- Annex 3: GKS FORTRAN enumeration type mnemonics.- VII. Case Study of GKS Development.- 1. Introduction.- 1.1 Our Requirements.- 1.2 Objectives of GKS.- 1.3 Design Phases.- 1.4 Overall Structure of our GKS System.- 2. Output and Attributes.- 2.1 The Workstation Interface.- 2.2 Handling of Attributes.- 2.3 Handling of Transformations.- 2.4 Organization of 'Pipelines'.- 2.5 Design of Output Utilities.- 2.6 Problems with Error Handling.- 2.7 General Utilities.- 3. Input System.- 3.1 Problems with Level 'c' Input.- 3.2 Organization of Input System.- 3.3 Input Data Records.- 3.4 Two Problems with Input.- 4. Segments.- 4.1 Different Possible Design Structures.- 4.2 Communication with Central Segment Store.- 4.3 Design of Workstation-Independent Segment Storage.- 5. Metafiles.- 5.1 Developments in Metafile Standards.- 5.2 Requirements of GKS Metafile Interface.- 5.3 Some Problems with Metafiles.- 5.4 Future Developments in Metafile Support.- 6. Conclusions.- 6.1 Survey of Problems.- 6.2 Survey of Targets Achieved.- 6.3 Future Developments.- Reference.- VIII. Surface Design Foundations.- 1. Local Coordinates.- 2. Polynomial Curves.- 3. B-Spline Curves.- 4. Rational Curves.- 5. Tensor Product Polynomial Surfaces.- 6. B-Spline Surfaces.- 7. Triangular Polynomial Patches.- 8. Scattered Data Interpolation.- 9. Transfinite Methods.- References.- IX. Geometric Modelling - Fundamentals.- 1. The Objectives of Geometric Modelling.- 2. Early Models.- 3. Geometrically Complete Models.- 4. Conversions between Models.- Appendix 1: 2D Construction.- Appendix 2: 3D Constructions.- Appendix 3: Profile Constructions.- Appendix 4: Sculptured Surface Sectioning Algorithms.- X. Solid Modeling: Theory and Applications.- 1. Introduction.- 2. The Role of Solid Modeling in CAD.- 2.1 Design Cycle.- 2.2 Models for CAD.- 2.3 System Architecture Aspects.- 3. Solid Modeling Techniques.- 3.1 Taxonomy of Modeling Schemes.- 3.2 Wire Frames.- 3.3 Boundary Representations.- 3.4 Constructive Solid Geometry.- 3.5 Other Representations.- 4. Solid Modeling Applications.- 4.1 Visualization.- 4.2 Integral Properties.- 4.3 Kinematic Analysis.- 4.4 NC Verification.- 5. Concluding Remarks.- References.

Abstract: GKS has evolved from a long process of national /1,2,3,4/ and international /5,6/ discussion on standardization of graphical systems. One of the basic principles of the Graphical Kernel System GKS is the concept of workstations that are used to address a display terminal with several input devices. This is a basic conceptual difference to the GSPC core system /6/, which will be discussed in this paper.A workstation represents a collection of graphical devices that are operated in a coordinated fashion by an operator at a given site. The whole workstation is treated in GKS as one logical unit.GKS features two dimensional output to and input from single or multiple workstations. Besides basic line drawing primitives raster graphics primitives are supported. The coordinates are transformed in a two-stage transformation process where the first stage can be set for each primitive and the second can be set for each workstation. Furthermore the setting of a workstation specific pen and text table allows control of the appearance of all primitives on the corresponding workstation.A segment facility provides means for structuring a picture in subparts. Segments may be created and deleted, the segment attributes may be dynamically modified, and the segments may be transformed. They can be displayed simultaneously or alternatively on different workstations. A device independent segment storage serves for inserting segments into other segments.

Abstract: Prolog is a userful tool for geometry and graphics implementations because its primitives, such as unification, match the requiements of many geometric algorithms. During the last two years, we have implemented programs to solve several problems in Prolog, including a subset of the Graphical Kernel System, convex-hull calculation, planar graph traversal, recognition of groupings of objects, Boolean combinations of polygons using multiple precision rational numbers, and cartographic map overlay. Certain paradigms or standard forms of geometric programming in Prolog are becoming evident. They include applying a function to every element of a set, executing a procedure so long as a certain geometric pattern exists, and using unification to propagate a transitive function. This article describes the experiences, including paradigms of programming that seem useful, and finally lists what we see as a advantaes and disadvantages of Prolog.