Over the past few years, multi-touch user interfaces emerged from research prototypes into mass market products. This evolution has been mainly driven by innovative devices such as Apple's iPhone or Micro\-soft's Surface tabletop computer. Unfortunately, there seems to be a lack of software engineering abstractions in existing multi-touch development frameworks. Many multi-touch applications are based on hard-coded procedural low level event processing. This leads to proprietary solutions with a lack of gesture extensibility and cross-application reusability. We present Midas, a declarative model for the definition and detection of multi-touch gestures where gestures are expressed via logical rules over a set of input facts. We highlight how our rule-based language approach leads to improvements in gesture extensibility and reusability. Last but not least, we introduce JMidas, an instantiation of Midas for the Java programming language and describe how JMidas has been applied to implement a number of innovative multi-touch gestures.
Scholiers, C., Hoste, L., Signer, B. and De Meuter, W.: "Midas: A Declarative Multi-Touch Interaction Framework", Proceedings of the 5th International Conference on Tangible, Embedded and Embodied Interaction (TEI 2011), Funchal, Portugal, January 2011