Showing papers on "Graphics published in 1985"

Juno, a constraint-based graphics system

Abstract: Juno is a system that harmoniously integrates a language for describing pictures with a what-you-see-is-what-you-get image editor. Two of Juno's novelties are that geometric constraints are used to specify locations, and that the text of a Juno program is modified in response to the interactive editing of the displayed image that the program produces.

Applications and Extensions of SADT

Abstract: Embodying an organized discipline of thought and action, the SADT methodology has been successful in many applications previously thought too nebulous for technical treatment. At the time the definitive papers on SADT,* Sofrech's Structured Analysis and Design Technique, were published in 1977,1-3 the methodology had been in extensive development and use for several years. Originally introduced as a "system-blueprinting" method for documenting the architecture of large and complex systems,4 SADT had become a full-scale methodology for coping with complexity through a team-oriented, organized discipline of thought and action, accompanied by concise, complete, and readable word and picture documentation. SADT broke new ground in the areas of problem analysis, requirements definition, and functional specification because it allowed rigorous expression of high-level ideas that previously had seemed too nebulous to treat technically. In the seven years since its introduction, SADT and its derivatives and extensions have been successfully applied to hundreds of major projects in a very broad range of application areas. An overview of this application experience and a look toward the future development of SADT are the subjects of this article. What is SADT? SADT consists of two principal parts: (1) the box-and-arrow diagram-*SADT is a trademark of SofTech, Inc. ming language of structured analysis and (2) the design technique, which is the discipline of thought and action that must be learned and practiced if the language is to be used effectively. Both parts are intimately related. Without the simplicity, generality, readability, and rigor of the SA dia-gramming language, the important ideas of the DT methodology would not be sufficiently visible and tangible to be of any coherent use. But without the DT discipline, those same language features of SA would make it almost useless (so much so that in 1977 Softech laid proprietary claim to its methodology, even while placing all the specifics of the SA language in the public domain). The situation would be much like knowing the rules and notation of algebra (capable of extensive calculation in almost any domain) without having any guidance or experience in translating word problems into properly formulated expressions. Neither SA nor SADT solves problems. Both are tools that allow people to express, understand, manipulate, and check problem elements in ways previously not possible. All of SADT stems from a single premise: The human mind can accommodate any amount of complexity as long as it is presented in easy-to-grasp chunks that together …

Children's mental models of recursive logo programs*

Abstract: Children who had a year of Logo programming experience were asked to think-aloud about what brief Logo recursive programs will do, and then to predict with a hand-simulation of the programs what the Logo graphics turtle will draw when the program is executed. If discrepancies arose in this last phase, children were asked to explain them. A prevalent but misguided “looping” interpretation of Logo recursion was identified, and this robust mental model persisted even in the face of contradiction between what the program did when executed and the child's predictions for what it would do.

Graphics and Human Information Processing: A Review of Five Books

Abstract: Five books on charts and graphs are reviewed from the standpoint of cognitive psychology. The review focuses on properties of the human visual information-processing system, and it considers how well the recommendations offered by each book work within the strengths and weaknesses of that system. The books reviewed are Semiology of Graphs, by J. Bertin (translated by W. J. Berg) (1983); Graphical Methods for Data Analysis, by J. M. Chambers, W. S. Cleveland, B. Kleiner, and P. A. Tukey (1983); Mapping Information, by H. T. Fisher (1982); Statistical Graphics, by C. F. Schmid (1983); and The Visual Display of Quantitative Information, by E. R. Tufte (1983).

Techniques for conic splines

Abstract: A number of techniques are presented for making conic splines more effective for 2D computer graphics. We give a brief account of the theory of conic splines oriented to computer graphics. We make Pitteway's algorithm exact, and repair an "aliasing" problem that has plagued the algorithm since its introduction in 1967. The curvature-matching problem for conics is solved by way of a simple formula for curvature at an endpoint which permits curvature to be matched exactly at non-inflectior points and more closely than was previously realized possible at points of inflection. A formula for minimum-curvature-variation of conic splines is given. These techniques provide additional support for Pavlidis' position [6] that conics can often be very effective as splines.The work was motivated by, and provides much of the foundation for, an implementation of conic splines at Sun Microsystems as part of Sun's Pixrect graphics package, the lowest layer of Sun's graphics support.

Graphics display system with arbitrary overlapping viewports

Abstract: In this graphics display system with arbitrary overlapping viewports, a display graphics image is assembled by acquiring from a source of image graphics data line portions of said image defined by a set of sequential control word sequences contained in a control table. Advantageously, each control word sequence includes at least one first control word defining a line portion of single viewport, and a continuation field. At least some of the control word sequences also include at least one continuation control word which defines a line portion of another independent but overlapping viewport. To produce the display, the system includes means responsive to the control words for acquiring graphics data specified therein and providing the same for use in the displayable image. If the continuation field indicates the presence in the sequence of a continuation control word, the system acquires graphics data specified by the continuation control word and utilizes the same in the displayable image thereby producing a display with overlapping viewports.

Graphics and flow visualization in computational fluid dynamics

Abstract: Techniques for displaying two- and three-dimensional flowfield solutions are described. Several methods of illustrating flow structure are addressed including particle tracing, simulated oil flow, and shock finding. These are incorporated into an interactive graphics program for CFD flowfields, called PLOT3D. Emphasis is made on the difficulty in visualizing three-dimensional flow features, and the importance of color, fast 3D image manipulation, and dynamic movie play-back in displaying such flows. The need for advanced algorithms to identify shock waves, vortices, and separation lines is pointed out. It is likely that the supercomputer will be needed for this process because of the size of 3D and/or unsteady CFD databases.

Personalized graphics and text materials, apparatus and method for producing the same

Abstract: Apparatus and method for generating and combining for reproduction on a single format, standardized text, standardized graphics, personalized text and personalized graphics. The apparatus employs a computer into which personalized text and personalized graphics information is introduced. A variety of graphics are stored in the computer and compared with the personalized graphics information introduced into the computer. The apparatus combines the standardized text and graphics with the personalized text and graphics to provide a personalized text and graphics output.

Computer Graphics Programming: Gks - The Graphics Standard

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The Graphics PARCUM* System: A 3D Memory Based Computer Architecture for Processing and Display of Solid Models

Abstract: The concept of a computer architecture for processing and display of spatially ordered data is presented in this paper. The central part of the architecture is a memory cube in which the objects can be processed in their real shape as a three‐dimensional data array. The development has been rendered possible at reasonable costs through the rapid progress in the realm of VLSI‐memory technology.

Finite element modeling system

Abstract: A Finite Element Analysis system having intelligent, interactive user interface features allows engineers without specialized knowledge in mathematical modeling to easily and interactively solve diverse problems. The system includes a digitizer tablet having a segmented work surface for entering pictorial data and for alternately selecting among processing modes from a menu. Alternate displays on a status screen are automatically correlated with the user positioning of a stylus on the digitizer tablet surface to provide the user with the information he needs for a particular contemplated action. A graphics screen displays a dumb cursor which tracks the position of the stylus in the graphics workspace of the digitizer tablet. An intelligent cursor automatically drawn on the graphics screen by a computer processor identifies a site of interest nearest the current location of the dumb cursor. The intelligent cursor anticipates the user's action in a selected mode and constrains these actions to valid operations within that mode.

Interactive decision software and computer graphics for architectural and space planning

Abstract: We describe the development and successful implementation of a decision support system now being used by several leading firms in the architecture and space planning industries. The system, which we call SPDS (spatial programming design system) has the following characteristics: (i) user-friendly convenience features permitting architects and space planners to operate the system without being experienced programmers; (ii) interactive capabilities allowing the user to control and to manipulate relevant parameters, orchestrating conditions to which his or her intuition provides valuable input; (iii) informative and understandable graphics, providing visual displays of interconnections that the computer itself treats in a more abstract methematical form; (iv) convenient ways to change configurations, and to carry out ‘what if’ analyses calling on the system’s decision support capabilities; (v) a collection of new methods, invisible to the user, capable of generating good solutions to the mathematical programming problems that underlie each major design component. These new methods succeed in generating high quality solutions to a collection of complex discrete, highly nonlinear problems. While these problems could only be solved in hours, or not at all, with previously existing software, the new methods obtain answers in seconds to minutes on a minicomputer. Major users, including Dalton, Dalton, Newport, and Marshal Erdwin, report numerous advantages of the system over traditional architectural design methods.

Hardware/software trade‐offs for bitmap graphics on the blit

Abstract: The Blit is an experimental bitmap graphics terminal built for research into interactive computer graphics on the UNIX time-sharing system. The hardware is inexpensive and the graphics functions are implemented entirely in software. Nevertheless, the graphics performance of the Blit is comparable or superior to some displays with special-purpose graphics hardware. This paper explains the paradox by referring to some principles of design: the hardware and software should be designed together to complement each other; carefully designed software can outperform infelicitous hardware; and simplicity of design leads to efficiency of execution. These principles are illustrated by examples from the Blit hardware and software and comparisons with other systems.

Image Analysis of Brain Physiology

Abstract: To understand the mechanisms responsible for behavior, neuroscientists need a holistic, 3D view of the brain

An interactive approach for solving multi-objective optimization problems (interactive computer, nelder-mead simplex algorithm, graphics)

Abstract: Multi-objective optimization problems are characterized by the need to consider multiple, and possibly conflicting, objectives in the solution process. We present an approach based on the use of interactive computer graphics to obtain qualitative information from a user about approximate solutions. We then use this qualitative information to transform the multi-objective optimization problem into a single-objective optimization problem that we may solve using standard techniques. Preliminary convergence results for the Nelder-Mead simplex algorithm are presented. Techniques for updating the single-objective problem after each piece of information is obtained from the user are described. These techniques are based on the duality theory for linear and quadratic programming. A software system for the subclass of 1-dimensional curve-fitting problems is also described.

Stored program controlled system for creating and printing graphics bearing packaging

Abstract: Stored program controlled data processing apparatus operates in concert with display and printing equipment to create, modify and print graphics for consumer goods or other packaging applications. Packaging graphics are prepared by entering and defining plural image elements which may comprise photographic or other images, geometric form, text, or anything else capable of print reproduction. The evolving composite graphics are viewed on a computer display peripheral, and may be modified as desired. In accordance with varying aspects of the present invention, a display image is formed illustrating the packaging graphics "wrapped" around and onto the surface of a user-specified three dimensional form to present and evaluate the packaging in its intended application. Moreover, the wrapped three dimensional display can be rotated to view the packaging from diverse directions. Once in satisfactory form, the completed packaging design stored in computer memory is printed and reproduced as desired to satisfy a requirement for packaging materials.

There's more to menu systems than meets the screen

Abstract: Love playing with those fancy menu-based graphical user interfaces, but afraid to program one yourself for your own application? Do windows seem opaque to you? Are you scared of mice? Like what-you-see-is-what-you-get but don't know how to get what you want to see on the screen?Everyone agrees using systems like graphical document illustrators, circuit designers, and iconic file systems is fun, but programming user interfaces for these systems isn't as much fun as it should be. Systems like the Lisp Machines, Xerox D-Machines, and Apple Macintosh provide powerful graphics primitives, but the casual applications designer is often stymied by the difficulty of mastering the details of window specification, multiple processes, interpreting mouse input, etc.This paper presents a kit called EZWin, which provides many services common to implementing a wide variety of interfaces, described as generalized editors for sets of graphical objects. An individual application is programmed simply by creating objects to represent the interface itself, each kind of graphical object, and each command. A unique interaction style is established which is insensitive to whether commands are chosen before or after their arguments. The system anticipates the types of arguments needed by commands, preventing selection mistakes which are a common source of frustrating errors. Displayed objects are made "mouse-sensitive" only if selection of the object is appropriate in the current context. The implementation of a graphical interface for a computer network simulation is described to illustrate how EZWin works.

Graphics data processing apparatus for graphic image operations upon data of independently selectable pitch

Abstract: The graphics data processing apparatus performs graphic data processing operations by combining data from two image arrays in accordance with a predetermined operation. This raster operation involves forming an image array having a pixel color code for each pixel of the combined image array formed from a combination of the color codes of corresponding pixels of the source and destination image arrays. The present invention includes a pair of data registers which define the difference in memory address between vertically adjacent pixels for the respective image arrays. This difference in memory address between vertically adjacent pixels is called the pitch and corresponds generally to the width of the display image in address space when any horizontal blanking interval is taken into account. In the present invention such raster operations can be performed on data which is stored in formats of differing pitch. This capability enables standard typefaces and icons to be stored in a default pitch while still being usable for a variety of display applications. In addition, even in the case in which both the source and destination pitches are the same, the capability for controlling the pitch for raster operations permits the same graphics data processing apparatus to operate in a variety of display applications. Thus the flexibility of operation and ease of application to differing graphics display problems is enhanced.

Pipeline display control apparatus with logic for blocking graphics processor accesses to shared memory during selected main processor graphics operations

Abstract: A graphics display apparatus employs a general purpose or main microprocessor providing general control of the apparatus including receiving high-level graphic orders defining a desired graphic image from a host processor and dedicated graphics microprocessor connected to receive low-level graphic orders from the general microprocessor along a pipeline constituted by a shared buffer store. Pipeline control logic controls the pipeline by blocking the graphics processor which generally operates more quickly than the general processor until the latter has completed computation of all the low-level orders associated with a particular high-level order. The front-of-screen performance can be further improved by backing up the pipeline to repeat certain low-level orders rather than by obtaining these repeated orders by recomputation. Graphics hardware controlled by the graphics processor loads appropriate bit patterns into an all points addressable refresh buffer for subsequent display on a cathode ray tube monitor.

An Aspect of Aesthetics in Human-Computer Communications: Pretty Windows

Abstract: Aesthetics in user interfaces addresses font definitions, typesetting conventions, color combinations, graphics design considerations, high resolution for viewscreens, and the shapes of windows. Computer viewscreens are evolving into pictorial media, communicating information with visual immediacy. The more interesting interfaces make use of multiple windows, menus, icons, and other visual effects to waken and sustain user interest and effectiveness. A pretty window is a viewscreen window with the dimensions of a golden rectangle, a rectangle whose width and height form the golden ratio of Euclid. Psychologists believe golden rectangles are aesthetically more pleasing than arbitrary rectangles, and subjects tend to select them in preference to other rectangles in tests.

Simulation Program Generators: Code and Animation on a P.C.

Abstract: What is a program generator? It is an interactive software tool that translates the logic of a model described in a relatively general symbolism into the code of a simulation language and so enables a computer to mimic model behaviour."2 This facility gives the user the benefits of a simple symbolic input (especially valuable for use by those who are not conversant with programming practices) combined with the power of a high-level language in which to develop models of complex systems. Program generators for simulation have been available on mainframe computers since the beginning of the 1970s. With the advent of reliable FORTRAN compilers in the early part of this year, it has been possible to transfer the software onto 16-bit microcomputers. At the same time the development of intelligent bit-mapped graphics boards, for example the PLUTO system from IO Research, has made possible improved levels of model animation. Animation is a particular use of the topological information in a program generator. This paper describes a program generator, DRAFT, which has been transferred to an I.B.M. P.C. and shows how the technique has been extended to provide users with a low-cost, flexible and convenient method of generating model animation. The use of graphics standards has contributed to the power of the graphics support. With a program and graphics generator on a dedicated personal computer, it has been possible to animate a model of a robot system in 2 days, where the previous time for coding and the inclusion of graphics routines was of the order of 4-6 weeks. The animation requires modifications to the simulation support routines, in this case the SIMON library of FORTRAN subroutines. The analysis of this task has led to a modified SIMON/G library with a totally hidden graphics function. To invoke the animation facilities simply requires that the graphics support library is selected and that a graphics definition file is provided. This requires a minimal modification in the program generator, and consequently reliability is maintained.

A Survey of Graphics Standards and Their Role in Information Interchange

Abstract: / e in this issue, you can ut the efforts of several ns to integrate text, graph-and image descriptions into document format. However, al standardization activity in ea has just begun. Furthermore, e has been little progress in specify-details of the integration of these fferent technologies into an official national or international standard. However, current graphics standardization work provides a clear indication ofthe nature and function ofthe graphics components of these future standardized integrated document files.

An Investigation of the "Tables Versus Graphs" Controversy in a Learning Environment

Abstract: The study of computer graphics as decision aids has become popular among MIS researchers in the last several years. However, this area of research, like many others in management information systems, has been plagued with methodological problems and contradictory findings. In light of these difficulties, the current study examined the "tables versus graphs" controversy within a learning environment. Seventy-five MBA students were exposed to one of three experimental treatments and asked to develop financial forecasts for fictitious companies over five experimental trials. Following their forecasts for each firm, participants were provided with feedback on the quality of their decisions. The information presentation treatments were as follows:(l) traditional spreadsheet (tabular), (2) graphs using "standard" scaling, and (3) graphs using " nonstandard" scaling. Results suggest that, although graphics may initially demonstrate no advantage over tables, they do show an advantage i f decision makers are repeatedly exposed to the novel format and given feedback on their performance. L. arning will occur even when improper scaling is used. The implication is that the effectiveness of graphics as decision aids depends on practice. Researchers are encouraged to employ repeated measures, or longitudinal, designs when examining the tables-versus-graphs controversy. Introduction display methods. Similar conflicting results have been found when graphs and tables are compared for their How to best display data to decision makers has been a effects on interpretation speed, user preference, and deconcern to MIS researchers since Mason and Mitroff cision confidence (see Ives, 1982; MacDonald-Ross, (1973) first noted the importance of "presentation 1977). Of a total of 7 studies dealing with the impact of mode" in the design of information systems. A large porgraphics on decision quality, only one reports graphs to tion of this research effort has centered on comparing the be superior to tables; 3 conclude that tables are superior relative effectiveness of tables and graphs for the support to graphs, and 3 have found no difference between the of problem solving activities in business settings. Interest two formats (see DeSanctis, 1984). in "tables versus graphs" comparisons has intensified during the past few years as sophisticated, easy-to-use Why is it that computer graphics are not proving to be graphics technology has become incorporated into decimore useful as tools for supporting decision making? sion support systems. The underlying assumption in Several investigators who have found graphs to be fairly these studies is that graphics should facilitate clearer perineffective in improving decision quality have postulated ception of data relationships and trends over tables. that learning must occur before graphical output becomes meaningful to people (c.g., Lusk & Kersnick, 1979; The empirical research dealing with the effectiveness of Vernon, 1946). Business data traditionally has been disgraphs as decision aids has been quite controversial. played in tabular form. Consequently, decision makers Several studies have found graphs to be easier to interpret simply lack the experience needed to properly interpret than tables; others have found the reverse; and still others novel formats. This argument implies that practice in report no difference in interpretation accuracy for the two viewing graphs might improve their meaningfulness to