The “Model - Display view - Picking view - Controller” model is a refinement of the MVC architecture. It introduces the “Picking View” component, which offloads the need from the controller to analytically compute the picked element. We describe how using the MPDC architecture leads to benefits in terms of modularity and descriptive ability when implementing interactive components. We report on the use of the MDPC architecture in a real application: we effectively measured gains in controller code, which is simpler and more focused.
paper:
Conversy, S., Barboni, E., Navarre, D., Palanque, P. "Improving modularity of interactive software with the MDPC architecture". In Proceedings of EIS (Engineering Interactive Systems) conference 2007, joint HCSE 2007, EHCI 2007 and DSVIS 2007 conferences, Lecture Notes in Computer Science (to appear). Springer Verlag, 2007.
excerpt:
This work attempts to tackle the question often asked when disserting about the MVC model: what is a controller exactly? As inventors of MVC apply separation of concerns to interaction code, we can apply separation of concerns down to the Controller itself: in MVC, the controller handles picking, the backward translation of dimension of events to arguments for operations on the model, and the management of the interactive state of interactive components (as opposed to graphical state). In MDPC, the combination of the scene-graph (the picking view) and Leave/Enter events synthesis handles picking. The picking code is hence offloaded from the Controller code, which makes the controller simpler. In order to pass computed values from events to arguments for operations on the model, the old Controller has to transform dimensions of the events in the widget referential: hence, it is dependent on the View, as it must queried its parameters (such as the orientation) to compute the inverse transform. This backward translation from the dimensions of the events to arguments for operation on the model can be handled by the inverse transform mechanism in the MDPC model. We have shown how to do it functionally with rotated scrollbar and pie charts. If this translation is more complex, it can be dealt with with a similar mechanism to MVzmC’s one, i.e. a View Controller. Hence, in the MDPC architecture, what we call a controller is the piece of code that manages the interactive state of a component, i.e. the state-machine or the Petri Net that describes it.