[PATCH v2 libinput] gestures: if fingers don't move, force a gesture by finger position

[Peter Hutterer]

If the fingers rest on the touchpad without moving for a timeout, switch to
pinch or swipe based on the finger position. We already switched to two-finger
scrolling based on the timeout, now we also do so for 3 and 4 finger gestures.
This gives us better reaction to small movements.

This also fixes previously unreachable code: the test for the finger position
required at least 3 fingers down but was within a condition that ensured only
2 fingers were down. This was introduced in 11917061fe320c.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
Changes to v1:
- better commit message/comments
- dropped the finger_count > 2 check that was a dead condition before anyway

 src/evdev-mt-touchpad-gestures.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/evdev-mt-touchpad-gestures.c b/src/evdev-mt-touchpad-gestures.c
index 08c179d..de3ec4f 100644
--- a/src/evdev-mt-touchpad-gestures.c
+++ b/src/evdev-mt-touchpad-gestures.c
@@ -331,21 +331,23 @@ tp_gesture_handle_state_unknown(struct tp_dispatch *tp, uint64_t time)
 	int yres = tp->device->abs.absinfo_y->resolution;
 	int vert_distance;
 
-	/* for two-finger gestures, if the fingers stay unmoving for a
-	 * while, assume (slow) scroll */
-	if (tp->gesture.finger_count == 2) {
-		if (time > (tp->gesture.initial_time + DEFAULT_GESTURE_2FG_SCROLL_TIMEOUT)) {
+	if (time > (tp->gesture.initial_time + DEFAULT_GESTURE_2FG_SCROLL_TIMEOUT)) {
+		/* for two-finger gestures, if the fingers stay unmoving for a
+		 * while, assume (slow) scroll */
+		if (tp->gesture.finger_count == 2) {
 			tp_gesture_set_scroll_buildup(tp);
 			return GESTURE_STATE_SCROLL;
 		}
 
-		/* Else check if one finger is > 20mm below the others */
+		/* for 3+ finger gestures, check if one finger is > 20mm
+		   below the others */
 		vert_distance = abs(first->point.y - second->point.y);
 		if (vert_distance > 20 * yres &&
-		    tp->gesture.finger_count > 2 &&
 		    tp->gesture.enabled) {
 			tp_gesture_init_pinch(tp);
 			return GESTURE_STATE_PINCH;
+		} else {
+			return GESTURE_STATE_SWIPE;
 		}
 	}
 
-- 
2.9.3