Introduction

How can consistent user interfaces be created more easily? Several different approaches have been taken to achieving interface consistency, and are described in other chapters in this volume. Some of these approaches are managerial and rely on committees to define and enforce corporate standards for consistency. Others are less formal and rely on an evolving shared vision of corporate style communicated through outstanding example applications. Both of these approaches may use toolkits of standard interface components such as window frames and scroll bars to help developers adhere to a common style.

The approach taken by the Interactive Transaction Systems (ITS) project, and described in this chapter, ^[1] is to generate consistent interfaces automatically by the use of executable style rules. In ITS, an application is implemented separate from its interface. In contrast to the approaches described above, a given application can be matched with different sets of style rules, and hence run with a variety of interfaces. Conversely, the same set of style rules can be used to generate interfaces consistent across a variety of applications. Generating interfaces automatically reduces the need for graphic artists and human factors engineers to work on the interface for each application. Rather, such experts write rules which can be reused in many different applications.

We have implemented these ideas in two systems during the first two years of the ITS project.