Make tap detection less restrictive for multi-finger taps.

In order to distinguish tap gestures from short movements, the mechanism
checks whether the distance between the first and the last position of a
touch exceeds the 'maxdist' limit.  Some touchpads provide unreliable
coordinates when more than one contact is being made simultaneously, and
in this case the filter may be too strong - and superfluous, because only
one-finger contacts should trigger pointer movement.

diff --git a/sys/dev/wscons/wstpad.c b/sys/dev/wscons/wstpad.c
index ccd2b4b..65cd6b7 100644 (file)
--- a/sys/dev/wscons/wstpad.c
+++ b/sys/dev/wscons/wstpad.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: wstpad.c,v 1.28 2021/03/21 16:20:49 bru Exp $ */
+/* $OpenBSD: wstpad.c,v 1.29 2021/03/24 07:40:37 bru Exp $ */
 
 /*
  * Copyright (c) 2015, 2016 Ulf Brosziewski
@@ -657,14 +657,8 @@ wstpad_is_tap(struct wstpad *tp, struct tpad_touch *t)
        struct timespec ts;
        int dx, dy, dist = 0;
 
-       /*
-        * No distance limit applies if there has been more than one contact
-        * on a single-touch device.  We cannot use (t->x - t->orig.x) in this
-        * case.  Accumulated deltas might be an alternative, but some
-        * touchpads provide unreliable coordinates at the start or end of a
-        * multi-finger touch.
-        */
-       if (IS_MT(tp) || tp->tap.contacts < 2) {
+       /* Try to distinguish one-finger taps from short movements. */
+       if (tp->tap.contacts == (tp->ignore ? 2 : 1)) {
                dx = abs(t->x - t->orig.x) << 12;
                dy = abs(t->y - t->orig.y) * tp->ratio;
                dist = (dx >= dy ? dx + 3 * dy / 8 : dy + 3 * dx / 8);