Re: master 101bbd1392: Add support for pinch gestures to the XI2 build

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> Please explain how the angle deltas make sense as part of a pinch
> gesture, I don't think I understand that.

Basically, this delta is only reported by the X server when the finger
rotates _after_ a pinch gesture is detected, for example if the user
zooms in, and while doing so, also rotates his fingers.  The rationale
is that some applications might have a reason to handle these events
separately (such as to ignore them, or to do something else with them),
instead of simply rotating the display.

> We are talking about the situation that several pinch events were
> reported to Emacs since the last time it entered the idle loop and
> checked for input.  Which commands do you envision that would like to
> process only some of that gesture, and leave the rest in the input
> queue?  AFAIU, all it will do is cause some kind of "inertia", in that
> the reaction to user gestures will lag after the gestures.  Why would
> that make sense?

I see your point now.  I'll look into making keyboard.c merge multiple
pinch events in the event queue.