I'm afraid it is a bit more complex than that because Pocketbook. Needs tweaking in
registerEventAdjustHook
ie: asign event.type to C.EV.KEY for given types. Then its a matter of adding keycodes to
event_map
The constants used by inkview are in
https://github.com/koreader/koreader.../inkview_h.lua.
Apparently 40 is EVT_TOUCHUP and 42 is EVT_TOUCHMOVE. That doesn't make much sense
Anyhow: patches welcome. Don't expect the feature anytime soon unless a new maintainer appears in the wild and wants to tackle this.
My bad for giving you hopes. I expected something trivial as in android.