[PATCH 2/3] touchpad: When a clickpad is clicked post combined motion of all touches

[Hans de Goede]

When clicking a clickpad the user may want to switch fingers to move the
pointer around, without lifting so as to not release the button.

Switch to using combined motion of all touches when a clickpad is clicked to
allow this.

BugLink: https://bugs.freedesktop.org/show_bug.cgi?id=86807
Signed-off-by: Hans de Goede <hdegoede at redhat.com>
---
 src/evdev-mt-touchpad.c | 43 +++++++++++++++++++++++++++++++++++++++----
 1 file changed, 39 insertions(+), 4 deletions(-)

diff --git a/src/evdev-mt-touchpad.c b/src/evdev-mt-touchpad.c
index 7d2e21a..7cee73d 100644
--- a/src/evdev-mt-touchpad.c
+++ b/src/evdev-mt-touchpad.c
@@ -453,6 +453,10 @@ tp_twofinger_scroll_post_events(struct tp_dispatch *tp, uint64_t time)
 	if (tp_tap_dragging(tp))
 		return 0;
 
+	/* No 2fg scrolling while a clickpad is clicked */
+	if (tp->buttons.is_clickpad && tp->buttons.state)
+		return 0;
+
 	/* Only count active touches for 2 finger scrolling */
 	tp_for_each_touch(tp, t) {
 		if (tp_touch_active(tp, t))
@@ -592,11 +596,9 @@ tp_post_process_state(struct tp_dispatch *tp, uint64_t time)
 }
 
 static void
-tp_post_pointer_motion(struct tp_dispatch *tp, uint64_t time)
+tp_get_pointer_delta(struct tp_dispatch *tp, double *dx, double *dy)
 {
 	struct tp_touch *t = tp_current_touch(tp);
-	double dx, dy;
-	double dx_unaccel, dy_unaccel;
 
 	if (!t->is_pointer) {
 		tp_for_each_touch(tp, t) {
@@ -610,7 +612,40 @@ tp_post_pointer_motion(struct tp_dispatch *tp, uint64_t time)
 	    t->history.count < TOUCHPAD_MIN_SAMPLES)
 		return;
 
-	tp_get_delta(t, &dx, &dy);
+	tp_get_delta(t, dx, dy);
+}
+
+static void
+tp_get_active_touches_delta(struct tp_dispatch *tp, double *dx, double *dy)
+{
+	struct tp_touch *t;
+	double tdx, tdy;
+	unsigned int i;
+
+	for (i = 0; i < tp->real_touches; i++) {
+		t = tp_get_touch(tp, i);
+
+		if (!tp_touch_active(tp, t) || !t->dirty)
+			continue;
+
+		tp_get_delta(t, &tdx, &tdy);
+		*dx += tdx;
+		*dy += tdy;
+	}
+}
+
+static void
+tp_post_pointer_motion(struct tp_dispatch *tp, uint64_t time)
+{
+	double dx = 0.0, dy = 0.0;
+	double dx_unaccel, dy_unaccel;
+
+	/* When a clickpad is clicked, combine motion of all active touches */
+	if (tp->buttons.is_clickpad && tp->buttons.state)
+		tp_get_active_touches_delta(tp, &dx, &dy);
+	else
+		tp_get_pointer_delta(tp, &dx, &dy);
+
 	tp_filter_motion(tp, &dx, &dy, &dx_unaccel, &dy_unaccel, time);
 
 	if (dx != 0.0 || dy != 0.0 || dx_unaccel != 0.0 || dy_unaccel != 0.0) {
-- 
2.1.0