All displays have an associated discrete coordinate system whether it is a pdf document, mobile device screen, a web page, a desktop or laptop. Naïve users are unable to pose them as an inverse formulation of popular world space to viewport mapping. The objective in this paper is twofold: (1) pose inverse formulation of two dimensional world space to viewport mapping, (2) generalize it as a rectangle to rectangle mapping along with innovative application perspective. This formulation mainly requires physical device dimensions, i.e., origin, width and height along with input device interaction usually mouse or sensor. Possible interactive applications are: (1) fingle or mouse swipe action, (2) mouse hover action on geographical map, (3) cursor tracker, (4) touch tester, (5) shape tweener and/or deformer, (6) connect the dots, (7) ripple generator, etc. Experimentation can be done on any programming platform with support for image processing and vector supported graphics pipeline.

world to viewport mapping, inverse mapping, linear interpolation or tweening, mouse tracking.