1. A computing device, comprising: a processor; a display screen including a transmissive layer and an active layer, the transmissive layer having a diffractive pattern configured to direct at least a portion of light incident on the display screen to a plurality of light sensors near at least one edge of the transmissive layer; and memory including instructions that, when executed by the processor, cause the computing device to: detect an intensity of light incident at each of a plurality of regions of a display screen using the plurality of light sensors analyze variations in the detected intensity to determine at least one region having a lower intensity value than at least one other region of the display screen, the lower intensity value being indicative of at least one shadow cast on the display screen; determine, based at least in part upon one or more characteristics of the at least one shadow, a position of a feature with respect to the device.