The Programmers\u27 Playground is a software library and run-time system for creating distributed multimedia applications from collections of reusable software moduels. This paper presents the design and implementation of EUPHORIA, Playground\u27s user interface management system. Implemented as a Playground module, EUPHORIA allows end-users to create direct manipulation graphical user interfaces (GUIs) exclusively through the use of a graphics editor. No programming is required. At run-time, attributes of the GUI state can be exposed and connected to external Playground modules, allowing the user to vosualize and directly manipulate state information in remote Playground modules. Features of EUPHORIA include real-time direct manipulation graphics, constraint-based editing and visualization, imaginary alignment objects, user-definable types, and user-definable widgets with alternative representations
