[E-devel] Multi-touch callbacks?

I've been using EFL to build applications for a few years now and have been
very pleased with the results the libraries enable. I have a new
requirement to implement pinch-and-zoom so I need to start exploring
multitouch but I'm running into a few issues getting it working.

I'm testing on my laptop which has a multitouch monitor and can confirm
that the driver is emitting the correct kernel MT protocol events via
evtest. For example, performing a small two finger drag I see two points
reported and updated before release:


Event: time 1630799195.877440, type 3 (EV_ABS), code 47 (ABS_MT_SLOT),
value 0
Event: time 1630799195.877440, type 3 (EV_ABS), code 57
(ABS_MT_TRACKING_ID), value 2
Event: time 1630799195.877440, type 3 (EV_ABS), code 53
(ABS_MT_POSITION_X), value 6621
Event: time 1630799195.877440, type 3 (EV_ABS), code 54
(ABS_MT_POSITION_Y), value 3292
Event: time 1630799195.877440, type 1 (EV_KEY), code 330 (BTN_TOUCH), value
1
Event: time 1630799195.877440, type 3 (EV_ABS), code 0 (ABS_X), value 6621
Event: time 1630799195.877440, type 3 (EV_ABS), code 1 (ABS_Y), value 3292
Event: time 1630799195.877440, -------------- SYN_REPORT ------------
Event: time 1630799195.885821, type 3 (EV_ABS), code 47 (ABS_MT_SLOT),
value 1
Event: time 1630799195.885821, type 3 (EV_ABS), code 57
(ABS_MT_TRACKING_ID), value 3
Event: time 1630799195.885821, type 3 (EV_ABS), code 53
(ABS_MT_POSITION_X), value 5302
Event: time 1630799195.885821, type 3 (EV_ABS), code 54
(ABS_MT_POSITION_Y), value 3490
Event: time 1630799195.885821, -------------- SYN_REPORT ------------
Event: time 1630799195.943159, type 3 (EV_ABS), code 57
(ABS_MT_TRACKING_ID), value -1
Event: time 1630799195.943159, -------------- SYN_REPORT ------------
Event: time 1630799195.961918, type 3 (EV_ABS), code 47 (ABS_MT_SLOT),
value 0
Event: time 1630799195.961918, type 3 (EV_ABS), code 57
(ABS_MT_TRACKING_ID), value -1
Event: time 1630799195.961918, type 1 (EV_KEY), code 330 (BTN_TOUCH), value
0

Next, I compiled EFL with the flags: disable-tslib, enable-xinput22, and
enable-always-build-examples. I made a few logging additions to the
 evas_multi_touch example so it'd print on MULTI_x callbacks, but I'm only
seeing MOUSE_x callbacks. My understanding is that the first touch point
would be reported as a MOUSE_DOWN/MOUSE_MOVE, and the second concurrent
point would be reported as a MULTI_x. Is this correct, and am I missing
something? I'm fairly confident that the driver itself is doing the correct
thing, but I'm a bit unsure about the interaction between EFL and X (N.B.,
the context is an OpenGL X window).

If anybody has any suggestions or a direction they can point me from here
I'd be very grateful.

Cheers,
Dave.