An apparatus comprising: an interactive display, having a front surface including a viewing area, and providing an input/output (I/O) interface for a user of an electronic device; a planar light guide disposed substantially parallel to the front surface and having a periphery at least coextensive with the viewing area, the planar light guide being disposed on or above and proximate to the front surface; a light-emitting source disposed outside the periphery of the planar light guide, the light-emitting source being optically coupled with an input of the planar light guide; a planar light collecting device; a plurality of light sensors disposed outside the periphery of the planar light guide; and a processor for recognizing, from outputs of the light sensors, an instance of a user gesture, and for controlling one or both of the interactive display and the electronic device, responsive to the user gesture; wherein, the planar light guide includes a first light-turning arrangement that outputs reflected light, in a direction having a substantial component orthogonal to the front surface, by reflecting emitted light received from the light-emitting source; the light collecting device is configured to collect scattered light, the collected scattered light resulting from interaction of the reflected light with an object; the light collecting device includes a second light-turning arrangement that redirects the collected scattered light toward one or more of the light sensors; each light sensor is configured to output a signal representative of a characteristic of the redirected collected scattered light. an interactive display, having a front surface including a viewing area, and providing an input/output (I/O) interface for a user of an electronic device; a planar light guide disposed substantially parallel to the front surface and having a periphery at least coextensive with the viewing area, the planar light guide being disposed on or above and proximate to the front surface; a light-emitting source disposed outside the periphery of the planar light guide, the light-emitting source being optically coupled with an input of the planar light guide; a planar light collecting device; a plurality of light sensors disposed outside the periphery of the planar light guide; and a processor for recognizing, from outputs of the light sensors, an instance of a user gesture, and for controlling one or both of the interactive display and the electronic device, responsive to the user gesture; wherein, the planar light guide includes a first light-turning arrangement that outputs reflected light, in a direction having a substantial component orthogonal to the front surface, by reflecting emitted light received from the light-emitting source; the light collecting device is configured to collect scattered light, the collected scattered light resulting from interaction of the reflected light with an object; the light collecting device includes a second light-turning arrangement that redirects the collected scattered light toward one or more of the light sensors; each light sensor is configured to output a signal representative of a characteristic of the redirected collected scattered light. the planar light guide includes a first light-turning arrangement that outputs reflected light, in a direction having a substantial component orthogonal to the front surface, by reflecting emitted light received from the light-emitting source; the light collecting device is configured to collect scattered light, the collected scattered light resulting from interaction of the reflected light with an object; the light collecting device includes a second light-turning arrangement that redirects the collected scattered light toward one or more of the light sensors; each light sensor is configured to output a signal representative of a characteristic of the redirected collected scattered light.