[PATCH libinput 11/11] touchpad: put a movement threshold on thumb detection

[Peter Hutterer]

If a thumb moves around, it's not resting and we should consider it a normal
touch.

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 src/evdev-mt-touchpad.c | 16 ++++++++++++++++
 src/evdev-mt-touchpad.h |  1 +
 test/touchpad.c         | 31 ++++++++++++++++++++++++++++---
 3 files changed, 45 insertions(+), 3 deletions(-)

diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index 0b39bf6..63ce488 100644
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -636,6 +636,22 @@ tp_thumb_detect(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
 		goto out;
 	}
 
+	/* If the thumb moves by more than 7mm, it's not a resting thumb */
+	if (t->state == TOUCH_BEGIN)
+		t->thumb.initial = t->point;
+	else if (t->state == TOUCH_UPDATE) {
+		struct device_float_coords delta;
+		struct normalized_coords normalized;
+
+		delta = device_delta(t->point, t->thumb.initial);
+		normalized = tp_normalize_delta(tp, delta);
+		if (normalized_length(normalized) >
+			TP_MM_TO_DPI_NORMALIZED(7)) {
+			t->thumb.state = THUMB_STATE_NO;
+			goto out;
+		}
+	}
+
 	/* Note: a thumb at the edge of the touchpad won't trigger the
 	 * threshold, the surface area is usually too small. So we have a
 	 * two-stage detection: pressure and time within the area.
diff --git a/src/evdev-mt-touchpad.h b/src/evdev-mt-touchpad.h
index 89801d6..0dfc6ac 100644
--- a/src/evdev-mt-touchpad.h
+++ b/src/evdev-mt-touchpad.h
@@ -204,6 +204,7 @@ struct tp_touch {
 	struct {
 		enum tp_thumb_state state;
 		uint64_t first_touch_time;
+		struct device_coords initial;
 	} thumb;
 };
 
diff --git a/test/touchpad.c b/test/touchpad.c
index 875bc58..25db43f 100644
--- a/test/touchpad.c
+++ b/test/touchpad.c
@@ -4054,15 +4054,39 @@ START_TEST(touchpad_thumb_update_no_motion)
 
 	litest_drain_events(li);
 
+	litest_touch_down(dev, 0, 59, 99);
+	litest_touch_move_extended(dev, 0, 59, 99, axes);
+	litest_touch_move_to(dev, 0, 60, 99, 80, 99, 10, 0);
+	litest_touch_up(dev, 0);
+
+	litest_assert_empty_queue(li);
+}
+END_TEST
+
+START_TEST(touchpad_thumb_moving)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+	struct axis_replacement axes[] = {
+		{ ABS_MT_PRESSURE, 190 },
+		{ -1, 0 }
+	};
+
+	litest_disable_tap(dev->libinput_device);
+	enable_clickfinger(dev);
+
+	if (!has_thumb_detect(dev))
+		return;
+
+	litest_drain_events(li);
+
 	litest_touch_down(dev, 0, 50, 99);
 	litest_touch_move_to(dev, 0, 50, 99, 60, 99, 10, 0);
-	litest_assert_only_typed_events(li, LIBINPUT_EVENT_POINTER_MOTION);
-
 	litest_touch_move_extended(dev, 0, 65, 99, axes);
 	litest_touch_move_to(dev, 0, 65, 99, 80, 99, 10, 0);
 	litest_touch_up(dev, 0);
 
-	litest_assert_empty_queue(li);
+	litest_assert_only_typed_events(li, LIBINPUT_EVENT_POINTER_MOTION);
 }
 END_TEST
 
@@ -4520,6 +4544,7 @@ litest_setup_tests(void)
 
 	litest_add("touchpad:thumb", touchpad_thumb_begin_no_motion, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:thumb", touchpad_thumb_update_no_motion, LITEST_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:thumb", touchpad_thumb_moving, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:thumb", touchpad_thumb_clickfinger, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:thumb", touchpad_thumb_btnarea, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:thumb", touchpad_thumb_edgescroll, LITEST_CLICKPAD, LITEST_ANY);
-- 
2.4.3