touchpad: move the tapping exclusion zone to the top edge of the button

We previously used the half-way mark of the touchpad's y axis to decide where
to ignore tapping. Move this down to the top edge of the software buttons
instead. Users may tap with a finger in the software button areas, on the rest
of the touchpad it's unlikely that they tap within 5% of the edge.

On touchpads with physical buttons or if clickfinger is enabled, the
no-tapping zone extends to the bottom of the touchpad. This required splitting
the tests into clickfinger, softbuttons and hardbuttons.

https://bugs.freedesktop.org/show_bug.cgi?id=93947

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>

src/evdev-mt-touchpad.c

@@ -538,9 +538,9 @@ tp_palm_tap_is_palm(const struct tp_dispatch *tp, const struct tp_touch *t)
 	    t->point.x < tp->palm.right_edge)
 		return false;
 
-	/* We're inside the left/right palm edge and in the northern half of
+	/* We're inside the left/right palm edge and not in one of the
-	 * the touchpad - this tap is a palm */
+	 * software button areas */
-	if (t->point.y < tp->palm.vert_center) {
+	if (t->point.y < tp->buttons.bottom_area.top_edge) {
 		log_debug(tp_libinput_context(tp),
 			  "palm: palm-tap detected\n");
 		return true;
@@ -1824,14 +1824,12 @@ static int
 tp_init_palmdetect(struct tp_dispatch *tp,
 		   struct evdev_device *device)
 {
-	int width, height;
+	int width;
 
 	tp->palm.right_edge = INT_MAX;
 	tp->palm.left_edge = INT_MIN;
-	tp->palm.vert_center = INT_MIN;
 
 	width = device->abs.dimensions.x;
-	height = device->abs.dimensions.y;
 
 	/* Wacom doesn't have internal touchpads */
 	if (device->model_flags & EVDEV_MODEL_WACOM_TOUCHPAD)
@@ -1845,7 +1843,6 @@ tp_init_palmdetect(struct tp_dispatch *tp,
 	/* palm edges are 5% of the width on each side */
 	tp->palm.right_edge = device->abs.absinfo_x->maximum - width * 0.05;
 	tp->palm.left_edge = device->abs.absinfo_x->minimum + width * 0.05;
-	tp->palm.vert_center = device->abs.absinfo_y->minimum + height/2;
 
 	tp->palm.monitor_trackpoint = true;
 

src/evdev-mt-touchpad.h

@@ -321,7 +321,6 @@ struct tp_dispatch {
 	struct {
 		int32_t right_edge;		/* in device coordinates */
 		int32_t left_edge;		/* in device coordinates */
-		int32_t vert_center;		/* in device coordinates */
 
 		bool trackpoint_active;
 		struct libinput_event_listener trackpoint_listener;

test/touchpad.c

@@ -1031,7 +1031,7 @@ START_TEST(touchpad_palm_detect_no_palm_moving_into_edges)
 }
 END_TEST
 
-START_TEST(touchpad_palm_detect_tap)
+START_TEST(touchpad_palm_detect_tap_hardbuttons)
 {
 	struct litest_device *dev = litest_current_device();
 	struct libinput *li = dev->libinput;
@@ -1051,7 +1051,38 @@ START_TEST(touchpad_palm_detect_tap)
 	litest_touch_up(dev, 0);
 	litest_assert_empty_queue(li);
 
-	litest_touch_down(dev, 0, 5, 90);
+	litest_touch_down(dev, 0, 5, 99);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 95, 99);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+}
+END_TEST
+
+START_TEST(touchpad_palm_detect_tap_softbuttons)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	if (!touchpad_has_palm_detect_size(dev))
+		return;
+
+	litest_enable_tap(dev->libinput_device);
+	litest_enable_buttonareas(dev);
+
+	litest_drain_events(li);
+
+	litest_touch_down(dev, 0, 95, 5);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 5, 5);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 5, 99);
 	litest_touch_up(dev, 0);
 	litest_assert_button_event(li,
 				   BTN_LEFT,
@@ -1061,7 +1092,7 @@ START_TEST(touchpad_palm_detect_tap)
 				   LIBINPUT_BUTTON_STATE_RELEASED);
 	litest_assert_empty_queue(li);
 
-	litest_touch_down(dev, 0, 95, 90);
+	litest_touch_down(dev, 0, 95, 99);
 	litest_touch_up(dev, 0);
 	litest_assert_button_event(li,
 				   BTN_LEFT,
@@ -1073,6 +1104,37 @@ START_TEST(touchpad_palm_detect_tap)
 }
 END_TEST
 
+START_TEST(touchpad_palm_detect_tap_clickfinger)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	if (!touchpad_has_palm_detect_size(dev))
+		return;
+
+	litest_enable_tap(dev->libinput_device);
+	litest_enable_clickfinger(dev);
+
+	litest_drain_events(li);
+
+	litest_touch_down(dev, 0, 95, 5);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 5, 5);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 5, 99);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 95, 99);
+	litest_touch_up(dev, 0);
+	litest_assert_empty_queue(li);
+}
+END_TEST
+
 START_TEST(touchpad_left_handed)
 {
 	struct litest_device *dev = litest_current_device();
@@ -3933,7 +3995,9 @@ litest_setup_tests(void)
 	litest_add("touchpad:palm", touchpad_palm_detect_palm_becomes_pointer, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:palm", touchpad_palm_detect_palm_stays_palm, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:palm", touchpad_palm_detect_no_palm_moving_into_edges, LITEST_TOUCHPAD, LITEST_ANY);
-	litest_add("touchpad:palm", touchpad_palm_detect_tap, LITEST_TOUCHPAD, LITEST_ANY);
+	litest_add("touchpad:palm", touchpad_palm_detect_tap_hardbuttons, LITEST_TOUCHPAD, LITEST_CLICKPAD);
+	litest_add("touchpad:palm", touchpad_palm_detect_tap_softbuttons, LITEST_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:palm", touchpad_palm_detect_tap_clickfinger, LITEST_CLICKPAD, LITEST_ANY);
 	litest_add("touchpad:palm", touchpad_no_palm_detect_at_edge_for_edge_scrolling, LITEST_TOUCHPAD, LITEST_CLICKPAD);
 
 	litest_add("touchpad:left-handed", touchpad_left_handed, LITEST_TOUCHPAD|LITEST_BUTTON, LITEST_CLICKPAD);