This paper addresses the problem of modernizing graphical user interfaces of interactive applications by re-engineering their resource files in four phases: resource decompilation, which extracts resource files from the executable code of an interactive application; modeling the source user interface, which transforms extracted resources into a resource model; resource to user interface transformation, which transforms the resource model into a Concrete User Interface model, and forward engineering, which offers two alternatives: after editing the user interface model, a new interface could be generated or recompiled into a resource to be incorporated back. The paper motivates and details this re-engineering approach by focusing on methods and algorithms implemented in UsiResourcer, a software tool that reverse engineers MS Windows resource files into a Concrete User Interface Model for further process. A discussion on the generalization of the approach is also provided.

Businesses are more and more modernizing the legacy systems they developed with Rapid Application Development (RAD), so that they can benefit from the new platforms and technologies. In these systems, the Graphical User Interface (GUI) layout is implicitly given by the position of the GUI elements (i.e. coordinates). However, taking advantage of current features of GUI technologies often requires an explicit, high-level layout model. We propose a Model-Driven Engineering process to perform reverse engineering of RAD-built GUIs, which is focused on discovering the implicit layout, and produces a GUI model where the layout is explicit. Based on the information we obtain, other reengineering activities can be performed, for example, to adapt the GUI for mobile device screens.