Composing User Interfaces with Interviews G raphical user interfaces for workstation applications are inherently difficult to build without abstractions that simplify the implementation process. To help programmers create such interfaces, we considered the following questions: What sort of interfaces should be supported? What constitutes a good set of programming abstractions for building such interfaces? How does a programmer build an interface given these abstractions? Practical experience has guided our efforts to develop user interface tools that address these questions. We make the following observations: All user interfaces need nor look alike. I t is desirable to maintain a consistent "look and feel" across applications, but users often have different preferences. For example, one user may prefer pop-up menus, while another insists on pull-down menus. Our tools must therefore allow a broad range of interface styles and must be customizable on a per-user basis. User interfaces need not be purely graphical. Many application designers prefer iconic interfaces because they believe

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If judiciously applied, animation techniques can enhance the look and feel of computer applications that present a graphical human interface. Such techniques can smooth the rough edges and abrupt transitions common in many current graphical interfaces, and strengthen the illusion of direct manipulation that many interfaces strive to present. To date, few applications include such animation techniques. One possible reason is that animated interfaces are difficult to implement: they are difficult to design, place great burdens on programmers, and demand high-performance from underlying graphics systems.This article describes how direct manipulation human computer interfaces can be augmented with techniques borrowed from cartoon animators. In particular, we wish to improve the visual feedback of a direct manipulation interface by smoothing the changes of an interface, giving manipulated objects a feeling of substance and providing cues that anticipate the result of a manipulation. Our approach is to add support for animation techniques such as object distortion and keyframe interpolation, and to provide prepackaged animation effects such as animated widgets for common user interface interactions.To determine if these tools and techniques are practical and effective, we built a prototype direct manipulation drawing editor with an animated interface and used the prototype editor to carry out a set of human factors experiments. The experiments show that the techniques are practical even on standard workstation hardware, and that the effects can indeed enhance direct manipulation interfaces.

Current user interface too&its provide components that are complex and expensive. Programmers cannot use these components for many kinds of application data because the resulting implementation would be awkward and inefficient. We have defined a set of small, simple components, called glyphs, that programmers can use in large numbers to build user interfaces. To show that glyphs are simple and efficient, we have implemented a WYSIWYG document editor. The editor's performance is comparable to that of similar editors built with current tools, but its implementation is much simpler. We used the editor to create and print this paper.

If judiciously applied, the techniques of cartoon animation can enhance the illusion of direct manipulation that many human computer interfaces strive to present. In particular, animation can convey a feeling of substance in the objects that a user manipulates, strengthening the sense that real work is being done. This paper suggests some techniques that application programmers can use to animate direct manipulation interfaces, and it describes tools that programmers can use to easily incorporate the effects into their code. Our approach is based on suggesting a range of animation effects by distorting the view of the manipulated object. To explore the idea, we added a warping transformation capability to the Interviews user interface toolkit and used the new transformation to build a simple drawing editor that uses animated feedback. The editor demonstrates the effectiveness of the animation for simple operations, and it shows that the technique is practical even on standard workstation hardware.