Support for zoom in/out

I'm not even sure if this is a valid HID thing or if i.e. wireless touchpads do it some other way, but I'd love zooming support like pinch-to-zoom, but via some non-multitouch input. If anyone coming across this issue has any idea how to implement that, or an example like an open source mouse firmware or something, please do let me know.

The issue does not name a file, test, or entry point. First determine whether HID exposes a non-multitouch zoom gesture and look for an open-source mouse firmware example. The work is complete only when a concrete implementation path and expected zoom behavior are defined.

Written by the indexing model from the issue text.