Portuguese Meeting on Computer Graphics 1988 (LGCG 1988)

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    Transputers on the Computer Image Generation
    (The Eurographics Association, 2023) Pereira, João; Reis, Francisco; Vinagre, Carlos; Gomes, Mário R.; Madalena Quirino
    This paper discusses the design of a graphics board with parallel architecture based on Transputers and a resolution of 1024 x 1024 x 8 [1], namely: the processing unit (it plays the role of a display processor), the organization of the trame buffer and the vídeo output hardware which includes the vídeo controller and a RAMDAC (lookuptable + DACs).
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    An Icon User Interface For Geometric Modelling
    (The Eurographics Association, 2023) Teixeira, José Carlos; Rix, Joachim; Madalena Quirino
    The User Interface plays a very important role in the geometric modelling systems. Different approaches have been developed in the last years, with and without the use of graphic images. As the sight is the most important human sensory, more and more efforts have been made to design effective and powerful graphical ori- ented User Interfaces. Starting with general issues and guidelines for graphical User Interface design, the paper reports the DACAD User Interface approach. DACAD is an experi- mental system that uses the methods of the constructive geometry and the technical design knowledge as a basis to create and manipulate three dimensional models.
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    THESEUS on X
    (The Eurographics Association, 2023) Muth, Matthias; Jorge, Joaquim A. P.; Madalena Quirino
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    Automated Testing of Computer Graphics Systems
    (The Eurographics Association, 2023) Jorge, Joaquim Armando Pires; Ziegler, Rolf; Göbel, Martin; Madalena Quirino
    Graphics systems have become increasingly complex over the last years. Computer graphics standards provide the means to implement portable graphics applications. However, the goals aimed by the use of graphics standards cannot be achieved, unless the standards are not lent to certification. Methods and tools for testing graphics systems have been developed, such as the GKS conformance testing package. Current test tools rely heavily on operator judgement of pictorial output produced by implementations being tested. As graphics systems are becoming richer in functionality, the design of test cases becomes more difficult and error prone. Automated test methods should be devised to provide for certification methods more precise than those involving human judgement. ln particular, methods .for automatic picture testing should be devised. Graphics systems should also include functions to assist in automatic testing, in order to prevent t·he need for special externai devices such as cameras and image processing equipment. This paper focuses on the issues raised by automatic testing of graphics systems. Standard components are studied with regard to their ability to being tested. Recent technologies and their application to automatic testing are discussed.
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    Modeling and Visualization of Three-Dimensional Scenes
    (The Eurographics Association, 2023) Ferreira, F. Nunes; Sousa, A. Augusto; Branco, V. Afonso; Costa, A. Cardoso; Madalena Quirino
    A small group of the Computer Graphics and CAD team from INESC.North has dedicated a large part of its time effort in investigating "lmage Synthesis with Large Levei of Realism". Initially, studies involving the Acquisition, Modeling and Visualization of three dimensional scenes were carried out. Results obtained in this first phase were a solid modeller, and some versions of visibility algorithms. The modeller, which has been repeatedly improved, already exists as a functional version for a UNIX workstation. It has been installed with locally adapted algorithms, which permit Ray-Tracing and Animation. The generation of surfaces through "Generalized Revolution", based on interpolation curves involving some original ideas, will soon be included. The Visibility Algorithms are still a target objective within our work. Some new ideas developed by the group in this area are now being explored. The working objectives of this group are: -the acquisition and modeling of three dimensional scenes -visualization with large levei of realism In the first case, we will be handled by image processing techniques; in the second, we will explore a set of new ideas in the area of Special Architecture for Computer Graphics, using the available technology as a base, but not putting aside investigation in the domain of VLSI technology for Computer Graphics. Themes to be developed: -Solid Modelling -Surface Generation through "Generalized Revolution" -Visibility
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    On programming an interactive graphical application in logic
    (The Eurographics Association, 2023) Próspero, Manuel João; Pereira, Paulo Jorge; Madalena Quirino
    A hierarchical graphical modelling system and a dialogue centrei mechanism were designed and implemented in first order predicate logic. Some main concepts are introduced in this papar by analysing a given application: a flat drawing design where the user is able to graphically specify the intended configuration and get important information about the existing restrictions.
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    Proceedings Info
    (The Eurographics Association, 2023) Madalena Quirino; Madalena Quirino
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    Archetype-oriented CHI A formal Approach to User Friendliness
    (The Eurographics Association, 2023) Oliveira, J. N.; Martins, F. M.; Madalena Quirino
    Theoretical computer science has the aim of formalizing previous empiri- cal, innovative creations in computing. The possibility of automatically con- structing instances of such creations is dependam on the existence of formal models. This is panicularly true in computing since computers do not manipulate informal models of problem-solutions. This paper describes an exercise in using constructive and algebraic specifica- tions in the formalization of some aspects of computer-human interaction (CHI). Formal specification can not only contribute to a better understanding of CHI, but also provide the almost non-existent link between CHI and Software Engineering. In this paper, from a modest analysis of user behaviour, we build mathematical models which lead to a formalization of the "standard" assisted-user-interface (AUI). These fonnalisms are applied to the specification of ASSIST, a mechani- cal generator of assisted-user-interfaces which matches with command-line parser-generators technology. Finally, we show how the assist-paradigm can be implicitly combined with fonnally specified software modules, in the sense that each formal specification itself contains enough information for ASSIST to gen- erate the relevant parts of the AUI.