Development of application front-ends that are designed for deployment on multiple devices requires facilities for specifying deviceindependent semantics. This paper focuses on the user-interface requirements for specifying device-independent layout constraints. We describe a device independent application model, and detail a set of high-level constraints that support automated layout on a wide variety of target platforms. We then focus on the problems that are inherent in any single-view direct-manipulation WYSIWYG interface for specifying such constraints. We propose a two-view interface designed to address those problems, and discuss how this interface effectively meets the requirements of abstract specification for pervasive applications.