touchpad: don't init a horizontal scroll area on touchpads <50mm high

We simply don't have enough space on those touchpads to have an area carved
out for horizontal scrolling. Given that horizontal scrolling is rarely needed
anyway users of these touchpads will just have to cling to scroll bars or use
two-finger scrolling.

Exception are small clickpads because they already have an area blocked off
for software buttons and those small clickpads generally come from a time when
clickfinger wasn't much of a thing yet.

https://bugs.freedesktop.org/show_bug.cgi?id=96910

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

src/evdev-mt-touchpad-edge-scroll.c

@@ -286,13 +286,29 @@ tp_edge_scroll_init(struct tp_dispatch *tp, struct evdev_device *device)
 {
 	struct tp_touch *t;
 	int edge_width, edge_height;
+	double width, height;
+	bool want_horiz_scroll = true;
+
+	/* Touchpads smaller than 50mm are not tall enough to have a
+	   horizontal scroll area, it takes too much space away. But
+	   clickpads have enough space here anyway because of the
+	   software button area (and all these tiny clickpads were built
+	   when software buttons were a thing, e.g. Lenovo *20 series)
+	 */
+	if (!tp->buttons.is_clickpad) {
+	    evdev_device_get_size(device, &width, &height);
+	    want_horiz_scroll = (height >= 50);
+	}
 
 	/* 7mm edge size */
 	edge_width = device->abs.absinfo_x->resolution * 7;
 	edge_height = device->abs.absinfo_y->resolution * 7;
 
 	tp->scroll.right_edge = device->abs.absinfo_x->maximum - edge_width;
+	if (want_horiz_scroll)
 		tp->scroll.bottom_edge = device->abs.absinfo_y->maximum - edge_height;
+	else
+		tp->scroll.bottom_edge = INT_MAX;
 
 	tp_for_each_touch(tp, t) {
 		t->scroll.direction = -1;

test/touchpad.c

@@ -450,11 +450,51 @@ START_TEST(touchpad_edge_scroll_vert)
 }
 END_TEST
 
+static int
+touchpad_has_horiz_edge_scroll_size(struct litest_device *dev)
+{
+	double width, height;
+	int rc;
+
+	rc = libinput_device_get_size(dev->libinput_device, &width, &height);
+
+	return rc == 0 && height >= 50;
+}
+
 START_TEST(touchpad_edge_scroll_horiz)
 {
 	struct litest_device *dev = litest_current_device();
 	struct libinput *li = dev->libinput;
 
+	if (!touchpad_has_horiz_edge_scroll_size(dev))
+		return;
+
+	litest_drain_events(li);
+	litest_enable_edge_scroll(dev);
+
+	litest_touch_down(dev, 0, 20, 99);
+	litest_touch_move_to(dev, 0, 20, 99, 70, 99, 10, 0);
+	litest_touch_up(dev, 0);
+
+	libinput_dispatch(li);
+	litest_assert_scroll(li, LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL, 4);
+	litest_assert_empty_queue(li);
+
+	litest_touch_down(dev, 0, 70, 99);
+	litest_touch_move_to(dev, 0, 70, 99, 20, 99, 10, 0);
+	litest_touch_up(dev, 0);
+
+	libinput_dispatch(li);
+	litest_assert_scroll(li, LIBINPUT_POINTER_AXIS_SCROLL_HORIZONTAL, -4);
+	litest_assert_empty_queue(li);
+}
+END_TEST
+
+START_TEST(touchpad_edge_scroll_horiz_clickpad)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
 	litest_drain_events(li);
 	litest_enable_edge_scroll(dev);
 
@@ -476,6 +516,31 @@ START_TEST(touchpad_edge_scroll_horiz)
 }
 END_TEST
 
+START_TEST(touchpad_edge_scroll_no_horiz)
+{
+	struct litest_device *dev = litest_current_device();
+	struct libinput *li = dev->libinput;
+
+	if (touchpad_has_horiz_edge_scroll_size(dev))
+		return;
+
+	litest_drain_events(li);
+	litest_enable_edge_scroll(dev);
+
+	litest_touch_down(dev, 0, 20, 99);
+	litest_touch_move_to(dev, 0, 20, 99, 70, 99, 10, 0);
+	litest_touch_up(dev, 0);
+
+	litest_assert_only_typed_events(li, LIBINPUT_EVENT_POINTER_MOTION);
+
+	litest_touch_down(dev, 0, 70, 99);
+	litest_touch_move_to(dev, 0, 70, 99, 20, 99, 10, 0);
+	litest_touch_up(dev, 0);
+
+	litest_assert_only_typed_events(li, LIBINPUT_EVENT_POINTER_MOTION);
+}
+END_TEST
+
 START_TEST(touchpad_scroll_defaults)
 {
 	struct litest_device *dev = litest_current_device();
@@ -700,6 +765,9 @@ START_TEST(touchpad_edge_scroll_within_buttonareas)
 	struct litest_device *dev = litest_current_device();
 	struct libinput *li = dev->libinput;
 
+	if (!touchpad_has_horiz_edge_scroll_size(dev))
+		return;
+
 	litest_enable_buttonareas(dev);
 	litest_enable_edge_scroll(dev);
 	litest_drain_events(li);
@@ -728,6 +796,9 @@ START_TEST(touchpad_edge_scroll_buttonareas_click_stops_scroll)
 	struct libinput_event_pointer *ptrev;
 	double val;
 
+	if (!touchpad_has_horiz_edge_scroll_size(dev))
+		return;
+
 	litest_enable_buttonareas(dev);
 	litest_enable_edge_scroll(dev);
 	litest_drain_events(li);
@@ -775,6 +846,9 @@ START_TEST(touchpad_edge_scroll_clickfinger_click_stops_scroll)
 	struct libinput_event_pointer *ptrev;
 	double val;
 
+	if (!touchpad_has_horiz_edge_scroll_size(dev))
+		return;
+
 	litest_enable_clickfinger(dev);
 	litest_enable_edge_scroll(dev);
 	litest_drain_events(li);
@@ -4081,7 +4155,9 @@ litest_setup_tests(void)
 	litest_add("touchpad:scroll", touchpad_scroll_natural_edge, LITEST_TOUCHPAD, LITEST_SINGLE_TOUCH);
 	litest_add("touchpad:scroll", touchpad_scroll_defaults, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:scroll", touchpad_edge_scroll_vert, LITEST_TOUCHPAD, LITEST_ANY);
-	litest_add("touchpad:scroll", touchpad_edge_scroll_horiz, LITEST_TOUCHPAD, LITEST_ANY);
+	litest_add("touchpad:scroll", touchpad_edge_scroll_horiz, LITEST_TOUCHPAD, LITEST_CLICKPAD);
+	litest_add("touchpad:scroll", touchpad_edge_scroll_horiz_clickpad, LITEST_CLICKPAD, LITEST_ANY);
+	litest_add("touchpad:scroll", touchpad_edge_scroll_no_horiz, LITEST_TOUCHPAD, LITEST_CLICKPAD);
 	litest_add("touchpad:scroll", touchpad_edge_scroll_no_motion, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:scroll", touchpad_edge_scroll_no_edge_after_motion, LITEST_TOUCHPAD, LITEST_ANY);
 	litest_add("touchpad:scroll", touchpad_edge_scroll_timeout, LITEST_TOUCHPAD, LITEST_ANY);