One of the most difficult aspects of creating graphical, direct manipulation user interfaces is managing the relationships between the graphical objects on the screen and the application data structures that they represent. Coral (Constraint-based Object-oriented Relations And Language) is a new user interface toolkit under development that uses efficiently-implemented constraints to support these relationships. Using Coral, user interface designers can construct interaction techniques such as menus and scroll bars. More importantly, Coral makes it easy to construct direct-manipulation user interfaces specialized to particular applications. Unlike previous constraint-based toolkits, Coral supports defining constraints in the abstract, and then applying them to different object instances. In addition, it provides iteration constructs where lists of items (such as those used in menus) can be constrained as a group. Coral has two interfaces: a declarative interface that provides a convenient way to specify the desired constraints, and a procedural interface that will allow a graphical user interface management system (UIMS) to automatically create Coral calls.

/pdf/a-user-interface-toolkit-based-on-graphical-objects-and-hiki47wxm5.pdf

A user interface toolkit based on graphical objects and constraints

Many editors use the graphics capabilities of personal workstations to provide a visual editing environment. Such editors present graphical representations of familiar objects and allow the user to manipulate the representations directly. This style of interaction is usually more intuitive to the user than typing statements in a command language. However, implementing a graphical object editor has been a difficult undertaking. Though many packages exist that aid in the construction of graphical user interfaces, none are designed specifically for building graphical object editors. This is significant because there is a substantial semantic gap between general user interfaces and the functionality of graphical object editors. For example, user interface packages usually provide buttons, scroll bars, and ways to assemble them, but they do not offer primitives for building drawing editors that produce PostScript or schematic capture systems that produce netlists. Higher-level abstractions are needed to make such applications easier to develop.
Unidraw is a framework for creating object-oriented graphical editors in domains such as technical and artistic drawing, music composition, and circuit design. The Unidraw architecture simplifies the construction of these editors by providing programming abstractions that are common across domains. Unidraw defines four basic abstractions: components encapsulate the appearance and semantics of objects in a domain, tools support direct manipulation of components, commands define operations on components and other objects, and external representations define the mapping between components and the file format generated by the editor. Unidraw also supports multiple views, graphical connectivity and confinement, and dataflow between components. This thesis describes the Unidraw design, implementation issues, and three experimental domain-specific editors we have developed with Unidraw: a drawing editor, a user interface builder, and a schematic capture system. Our results indicate a substantial reduction in implementation time and effort compared with existing tools.

Generalized graphical object editing

Computer graphics and CAD literature—A keyword-indexed bibliography

One of the most important functions of an intelligent workstation is to provide a state-of-the-art user interface to distributed resources. One aspect of such an interface is virtual terminal support for both local and remote applications with a range of requirements, including graphics. To ensure good response for remote applications, in particular, the bulk of user interaction must be handled local to the workstation. Therefore, the terminal management software on the workstation must provide object modeling as well as viewing facilities, in contrast to most contemporary graphics systems. One way of doing this is to support structured display files. It is equally important to support simultaneous access to multiple applications; thus the terminal management software must provide window system Lscilities. Lastly, since the terminal management software should present a common interface to both local and remote applications, the workstation itself should be regarded as a multifunction component of the distributed system and not strictly as a terminal or a personal computer. This paper presents the system architecture and protocols necessary to achieve these goals and evaluates an existing implementation.

Structured Graphics for Distributed Systems

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.

https://link.springer.com/content/pdf/10.1057%2Fjors.1985.101.pdf

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

For the first time, an international graphics standard is possible. After years of research and redesign, the GKS emerges as the most likely candidate.

Encarnacao

Papers

GKSamdash;The First Graphics Standard