The Amulet user interface development environment makes it easier for programmers to create highly-interactive, graphical user interface software for Unix, Windows or Macintosh. Amulet uses new models for objects, constraints, animation, input, output, commands, and undo. The object system is a prototype-instance model in which there is no distinction between classes and instances or between methods and data. The constraint system allows any value of any object to be computed by arbitrary code and supports multiple constraint solvers. Animations can be attached to existing objects with a single line of code. Input from the user is handled by "Interactor" objects which support reuse of behavior objects. The output model provides a declarative definition of the graphics, and supports automatic refresh. Command objects encapsulate all of the information needed about operations, including support for various ways to undo them. An key feature of the Amulet design is that all graphical objec...

Almost as long as there have been user interfaces, there have been special software systems and tools to help design and implement the user interface software. Many of these tools have demonstrated significant productivity gains for programmers, and have become important commercial products. Others have proven less successful at supporting the kinds of user interfaces people want to build. This article discusses the different kinds of user interface software tools, and investigates why some approaches have worked and others have not. Many examples of commercial and research systems are included. Finally, current research directions and open issues in the field are discussed.

This article proposes and tests a two-component model for describing and programming the finegrained aspects of non-WIMP interaction. The model combines a data-flow or constraint-like component for the continuous relationships with an event-based component for discrete interactions, which can enable or disable individual continuous relationships. Its key ingredients are the separation of non-WIMP interaction into two components and the framework it provides for communication between the two

This dissertation defines and explores Graspable User Interfaces, an evolution of the input mechanisms used in graphical user interfaces (GUIs). A Graspable UI design provides users concurrent access to multiple, specialized input devices which can serve as dedicated physical interface widgets, affording physical manipulation and spatial arrangements. Like conventional GUIs, physical devices function as “handles” or manual controllers for logical functions on widgets in the interface. However, the notion of the Graspable UI builds on current practice in a number of ways. With conventional GUIs, there is typically only one graphical input device, such as a mouse. Hence, the physical handle is necessarily “time-multiplexed,” being repeatedly attached and unattached to the various logical functions of the GUI. A significant aspect of the Graspable UI is that there can be more than one input device. Hence input control can then be “space-multiplexed.” That is, different devices can be attached to different functions, each independently (but possibly simultaneously) accessible. This, then affords the capability to take advantage of the

. Ultraviolet is a constraint satisfaction algorithm intended for use in interactive graphical applications. It is capable of solving constraints over arbitrary domains using local propagation, and inequality constraints and simultaneous linear equations over the reals. To support this, Ultraviolet is a hybrid algorithm that allows different subsolvers to be used for different parts of the constraint graph, depending on graph topology and kind of constraints. In addition, Ultraviolet and its subsolvers support plan compilation, producing efficient compiled code that can be evaluated repeatedly to resatisfy a given collection of constraints for different input values. Keywords: constraints, user interfaces, hybrid constraint satisfaction algorithms 1. Introduction Many key aspects of interactive graphical systems can be conveniently described using constraints, including layout and other kinds of geometric relations, consistency between application data and views, consistency of multi...

In this paper, we present an expressive 3D animation environment that enables users to rapidly and visually prototype animated worlds with a fully 3D user-interface. A 3D device allows the specification of complex 3D motion, while virtual tools are visible mediators that live in the same 3D space as application objects and supply the interaction metaphors to control them. In our environment, there is no intrinsic difference between userinterface and application objects. Multi-way constraints provide the necessary tight coupling among components that makes it possible to seamlessly compose animated and interactive behaviors. By recording the effects of manipulations, all the expressive power of the 3D user interface is exploited to define animations. Effective editing of recorded manipulations is made possible by compacting all continuous parameter evolutions with an incremental data-reduction algorithm, designed to preserve both geometry and timing. The automatic generation of editable representations of interactive performances overcomes one of the major limitations of current performance animation systems. Novel interactive solutions to animation problems are made possible by the tight integration of all system components. In particular, animations can be synchronized by using constrained manipulation during playback. The accompanying video-tape illustrates our approach with interactive sequences showing the visual construction of 3D animated worlds. All the demonstrations in the video were recorded live and were not edited.

The success of constraint-based approaches to drawing has been limited by difficulty in creating constraints, solving them, and presenting them to users. In this paper, we discuss techniques used in the Briar drawing program to address all of these issues. Briar¼s approach separates the problem of initially establishing constraints from that of maintaining them during subsequent editing. We describe how non-constraint- based drawing tools can be augmented to specify constraints in addition to positions. These constraints are then maintained as the user drags the model, allowing the user to explore configurations consistent with the constraints. Visual methods are provided for displaying and editing the constraints.

Recent work is beginning to reveal the potential of numerical optimization as an approach to generating interfaces and displays. Optimization-based approaches can often allow a mix of independent goals and constraints to be blended in ways that would be difficult to describe algorithmically. While optimization-based techniques appear to offer several potential advantages, further research in this area is hampered by the lack of appropriate tools. This paper presents GADGET, an experimental toolkit to support optimization for interface and display generation. GADGET provides convenient abstractions of many optimization concepts. GADGET also provides mechanisms to help programmers quickly create optimizations, including an efficient lazy evaluation framework, a powerful and configurable optimization structure, and a library of reusable components. Together these facilities provide an appropriate tool to enable exploration of a new class of interface and display generation techniques.

This paper presents the architecture for an extensible toolkit used in construction and rapid prototyping of three dimensional interfaces, interactive illustrations, and three dimensional widgets. The toolkit provides methods for the direct manipulation of 3D primitives which can be linked together through a visual programming language to create complex constrained behavior. Features of the toolkit include the ability to visually build, encapsulate, and parameterize complex models, and impose limits on the models. The toolkit's constraint resolution technique is based on a dynamic object model similar to those in prototype delegation object systems. The toolkit has been used to rapidly prototype tools for mechanical modelling, scientific visualization, construct 3D widgets, and build mathematical illustrations. 3D Interface Toolkit April 21, 1994 3 1.0 Introduction There have been many advances in 2D user interface toolkits [8][10][11][12] which allow developers to rapidly prototyp...

In order to support rapid prototyping and efficient construction of user interface software, the Amulet user interface development environment uses a prototype-instance object model integrated with a constraint solver. The important innovations in the Amulet object and constraint systems are the automatic management of a part-owner hierarchy in addition to the prototype instance hierarchy, the support for multiple constraint solvers at the same time, control over slot inheritance, flexible demons, and a convenient integration of the models with C++ without requiring a pre-processor. This research was sponsored by NCCOSC under Contract No. N66001-94-C-6037, ARPA Order No. B326. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the official policies, either expressed or implied, of NCCOSC or the U.S. Government.