Volume 08 (1989)
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Item MICRO-UIDT: A User Interface Development Tool(Eurographics Association, 1989) Mao, QijingA user interlace development tool called Micro-UIDT is described. Micro-UIDT provides an interactive design environment fur the user interface designers. The designing language for defining user interfaces are visual and nonprocedural. State transition diagrams are used as the notation for specifying man-machine dialogue control. Some extensions are added into the notation, so that the user interfaces with semantic feedback can be defined. The approach of specifying the presentation of application data is bottom-up and direct operation. The designing language for this has two major description facilities, one for describing graphics and another for describing the relationships between the graphics and the application variables. A concept of graphic object is used in the language, which can make the design result be abstracted and reused. The user interfaces developed with Micro-UIDT are small in size and fast in speed.Item Message-Based Object-Oriented Interaction Modeling(Eurographics Association, 1989) Breen, David E.; Kühn, VolkerThis paper describes a message-based object-oriented tool for exploring mathematically-based interactions which produce complex motions for computer animation. The tool has been implemented as an object in the object-oriented computer animation system The Clockworks. It supports the definition of complex interactions between geometric objects through the specification of messages to the interacting objects. Our approach is general, flexible and powerful. The tool itself is not hardcoded to a particular application. It simply sends the messages specified by the user. Messages are specified as strings which may be stored, modified and interpreted. Since the tool is part of The Clockworks it may utilize many of the powerful features of the system, including data structuring, mathematical, geometric modeling, and rendering objects. The tool has been used to explore a general spring and mass model, and the response of objects in a vector field.Item Book Reviews(Blackwell Publishing Ltd and the Eurographics Association, 1989)Book reviewed in this article:Title: Image Synthesis - Elementary Algorithms Author: Gerard Hegron Translation (by D. Beeson) of: Synthese d Image: Algorithmes ElementairesCurves and Surfaces in Computer Aided Geometric Design Author: F. YamaguchiItem Fourth Eurographics Workshop on Graphics Hardware(Blackwell Publishing Ltd and the Eurographics Association, 1989)Item Computer Graphics Forum Cover Competition(Blackwell Publishing Ltd and the Eurographics Association, 1989)Item Call for Participation in the EUROGRAPHICS WORKING GROUP on RELATIONSHIPS BETWEEN IMAGE SYNTHESIS and ANALYSIS(Blackwell Publishing Ltd and the Eurographics Association, 1989)Item Response to Morten Zachrisen s Note(Blackwell Publishing Ltd and the Eurographics Association, 1989) Herman, IvanItem The Line-Picture Attribute(Blackwell Publishing Ltd and the Eurographics Association, 1989) Gossling, T.H.The linetype attribute in GKS and PHIGS is required to cover a wide variety of renderings of the polyline primitive. The results are strongly implementation-dependent, widi virtually no user control. Splitting linetype into a one-dimensional line-pattern and a two-dimensional line-picture gives much greater flexibility, without the need to go through a registration process for every new style. The line-picture attribute, consisting of a single glyph repeated at intervals along a linear primitive, can answer many requirements in draughting for process industries, and should also be applicable elsewhere.Item Towards an Object-Oriented Interaction Model for Graphics User Interfaces(Blackwell Publishing Ltd and the Eurographics Association, 1989) Hubner, Wolfgang; de Lancastre, ManuelThe increasing importance of the User Interface Management System THESEUS stimulated the development of a formalized graphics input model that is based on the THESEUS input concepts. This paper presents cooperative work by the Zentrum fur Gra-phische Datenverarbeitung (ZGDV), West Germany and IST/INESC, Portugal which aims to formalize, generalize and enhance the THESEUS input model and transfer it to a clean object-oriented approach. The main goal was to establish concepts for specifying and managing user interfaces tailored to the requirements of graphics dialogues- among these concepts are the diversity of input devices, many different kinds of interaction techniques, higher complexity in dialogue structures, dynamic control over dialogue specification, a strong coupling of input and output instead of ping-pong sequencing, powerful output capabilities, support of continuous input operations and a close interlocking between user interface component and application.Item When is a Line a Line?(Eurographics Association, 1989) Brodlie, Ken W.; Göbel, Martin; Roberts, Ann; Ziegler, RolfConformance testing of graphics systems is a very complex and exhausting task. Years of practice with the GKS testing tools have shown a need for the automatic testing of visual output. Indeed, with regard to graphics systems which are more precisely specified than GKS like the Computer Graphics Interface (CGI), conformance testing is not manageable at all unless a major part can be automated. This paper discusses different strategies for the automatic testing of pictorial effect. It concentrates on the definition of lines and describes a strategy to answer the question put in the title by the testing system. Finally, automatic testing of simple graphical operations such as segment highlighting and visibility is discussed.Item Eurographics Workshop Relation of Page Description Languages and Graphics Systems(Blackwell Publishing Ltd and the Eurographics Association, 1989)Item The Problematics of Human Prototyping and Animation(Blackwell Publishing Ltd and the Eurographics Association, 1989) Magnenat-Thalmann, Nadia; Thalmann, DanielSeveral ideas and experiments are presented for the creation and realistic animation of three-dimensional scenes involving human beings conscious of their environment. The various approaches should allow the intelligent creation of human beings using prototypes and generate their animation based on mechanics, artificial intelligence and robotics. This paper discusses the problems involved in three major steps of the simulation of human beings: the creation of the human shapes, the motion of the human skeleton, and the deformation of the surfaces. Several examples are presented illustrating positional constraints, dynamics, behavioural animation and finite element theory.Item Toward Realistic Formal Specifications for Non-Trivial Graphical Objects(Eurographics Association, 1989) Fiume, EugeneFormal specification has long been advocated in programming methodology, and is becoming increasingly popular in computer graphics to characterise the semantics of components of graphics systems. Unfortunately, formal specifications tend to sacrifice realism for abstraction. The result is often a specification that is not as relevant to real graphics systems as it could be. This paper suggests that the use of sharper mathematical tools, together with the use of object orientation (i.e., data abstraction with inheritance) provides a way of resolving this problem. As an example, we attempt to specify formally classes of bitmaps and images. These are particularly interesting choices, for bitmaps and images are mutable, bitmaps can have a perceived effect on images, and their semantics depends on context.Item Forest of Quadtrees: An Object Representation for 3D Graphics(Eurographics Association, 1989) Kaufman, Arie; Bandopadhay, AmitA forest of quadtrees is proposed as an alternative data structure for representing and manipulating 3D and 2.5D graphics. A data representation of a forest offers space savings over common quadtrees by concentrating the vital information and discarding unused pointers. Several properties of the forest of quadtrees and the basic operations for display and elementary transformations like rotation, reflection, enlargement, reduction, and translation are investigated. Specifically, the temporary memory requirements and duplication time of the algorithms are analyzed.Item Offers to EUROGRAPHICS Members(Blackwell Publishing Ltd and the Eurographics Association, 1989)Item GKS, Structures and Formal Specification(Eurographics Association, 1989) Duce, D. A.There are now three International Standards for application program interfaces for computer graphics programming, GKS, GKS-3D and PHIGS. In this paper a simplified model GKS-like system is described and a 2D PHIGS-like system is then described in terms of this and a centralized structure store. Formal specifications of the systems are given illustrating how the specification of a system can be built up from a hierarchy of simple components. The purpose of the paper is to illustrate one approach to the description of a compatible family of graphics standards and the use of formal specification techniques in this process.Item Visualisation in Astrophysics(Eurographics Association, 1989) Ertl, T.; Geyer, F.; Herold, H.; Kraus, U.; Niemeier, R.; Nollert, H.- P.; Rebetzky, A.; Ruder, H.; Zeller, G.This paper reports on progress we have made in modelling cosmic X-ray sources on supercomputers. The results we present are meant to serve as an example for the fact that sophisticated visualization techniques play a crucial role in scientific computing. Among the graphical methods we demonstrate, raytracing in curved space-time and a physically motivated 3D-volume rendering algorithm might be of interest to the graphics community in general.Item The Structure of Tube - A Tool for Implementing Advanced User Interfaces(Eurographics Association, 1989) Hill, Ralph D.; Herrmann, MarcGood user interfaces are very costly to implement and maintain. As user interfaces become more advanced, moving to various forms of direct manipulation, they become even more expensive and difficult to implement. In the recent past, many user interface management systems and related tools for the rapid development of user interfaces have been developed. Some have been successful at reducing interface development costs for some styles of interface, but none fully address the requirements of advanced direct manipulation interfaces. We claim this is because they are founded on basic models and components that work only for simpler interaction styles. We present Tube, a tool for the rapid development of advanced direct manipulation user interfaces, describe its structure, and show how it differs from, and is better than, traditional structures.Item From The Chairman(Blackwell Publishing Ltd and the Eurographics Association, 1989) Hubbold, RogerItem Pixel Selected Ray Tracing(Eurographics Association, 1989) Akimoto, Taka-aki; Mase, Kenji; Hashimoto, Akihiko; Suenaga, YasuhitoThis paper presents a new ray-tracing acceleration technique called Pixel Selected Ray-Tracing (PSRT). PSRT uses undersampling based on Iterative Central Point Selection(ICPS) along with checking for similarities among trees in neighboring pixels. By using ICPS and trees, the largest danger of missing object borders can be drastically reduced. Although the speed increase attributable to PSRT varies with the image generation environment, according to experiments comparing PSRT with standard ray-tracing, PSRT is 2.6 to 8.2 times faster than standard ray-tracing for 512 by 512 pixel images, maintaining the same visual image quality. It is true that images generated by this method may contain very small errors. However, such errors can be reduced and may be made visually negligible by using ICPS and the trees of ray-object intersection to check for similarities.