touchpad: convert normalized_length to physical coordinates

Now that the acceleration code doesn't use dpi-normalized coordinates anymore,
we don't need to use them in the touchpad code. Switch to physical distances
instead, it makes debugging a lot saner.

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

src/evdev-mt-touchpad-gestures.c

@@ -186,18 +186,20 @@ tp_gesture_get_direction(struct tp_dispatch *tp, struct tp_touch *touch,
 			 unsigned int nfingers)
 {
 	struct normalized_coords normalized;
+	struct phys_coords mm;
 	struct device_float_coords delta;
-	double move_threshold = TP_MM_TO_DPI_NORMALIZED(1);
+	double move_threshold = 1.0; /* mm */
 
 	move_threshold *= (nfingers - 1);
 
 	delta = device_delta(touch->point, touch->gesture.initial);
+	mm = tp_phys_delta(tp, delta);
+
+	if (length_in_mm(mm) < move_threshold)
+		return UNDEFINED_DIRECTION;
 
 	normalized = tp_normalize_delta(tp, delta);
 
-	if (normalized_length(normalized) < move_threshold)
-		return UNDEFINED_DIRECTION;
-
 	return normalized_get_direction(normalized);
 }
 

src/evdev-mt-touchpad-tap.c

@@ -36,7 +36,7 @@
 #define DEFAULT_TAP_INITIAL_TIMEOUT_PERIOD ms2us(100)
 #define DEFAULT_TAP_TIMEOUT_PERIOD ms2us(180)
 #define DEFAULT_DRAG_TIMEOUT_PERIOD ms2us(300)
-#define DEFAULT_TAP_MOVE_THRESHOLD TP_MM_TO_DPI_NORMALIZED(1.3)
+#define DEFAULT_TAP_MOVE_THRESHOLD 1.3 /* mm */
 
 enum tap_event {
 	TAP_EVENT_TOUCH = 12,
@@ -734,11 +734,10 @@ static bool
 tp_tap_exceeds_motion_threshold(struct tp_dispatch *tp,
 				struct tp_touch *t)
 {
-	struct normalized_coords norm =
-		tp_normalize_delta(tp, device_delta(t->point,
-						    t->tap.initial));
+	struct phys_coords mm =
+		tp_phys_delta(tp, device_delta(t->point, t->tap.initial));
 
-	return normalized_length(norm) > DEFAULT_TAP_MOVE_THRESHOLD;
+	return length_in_mm(mm) > DEFAULT_TAP_MOVE_THRESHOLD;
 }
 
 static bool

src/evdev-mt-touchpad.c

@@ -751,12 +751,11 @@ tp_thumb_detect(struct tp_dispatch *tp, struct tp_touch *t, uint64_t time)
 		t->thumb.initial = t->point;
 	else if (t->state == TOUCH_UPDATE) {
 		struct device_float_coords delta;
-		struct normalized_coords normalized;
+		struct phys_coords mm;
 
 		delta = device_delta(t->point, t->thumb.initial);
-		normalized = tp_normalize_delta(tp, delta);
-		if (normalized_length(normalized) >
-			TP_MM_TO_DPI_NORMALIZED(7)) {
+		mm = tp_phys_delta(tp, delta);
+		if (length_in_mm(mm) > 7) {
 			t->thumb.state = THUMB_STATE_NO;
 			goto out;
 		}

src/evdev-mt-touchpad.h

@@ -399,6 +399,18 @@ tp_normalize_delta(const struct tp_dispatch *tp,
 	return normalized;
 }
 
+static inline struct phys_coords
+tp_phys_delta(const struct tp_dispatch *tp,
+	      struct device_float_coords delta)
+{
+	struct phys_coords mm;
+
+	mm.x = delta.x / tp->device->abs.absinfo_x->resolution;
+	mm.y = delta.y / tp->device->abs.absinfo_y->resolution;
+
+	return mm;
+}
+
 /**
  * Takes a dpi-normalized set of coordinates, returns a set of coordinates
  * in the x-axis' coordinate space.

src/libinput-private.h

@@ -699,6 +699,12 @@ normalized_is_zero(struct normalized_coords norm)
 	return norm.x == 0.0 && norm.y == 0.0;
 }
 
+static inline double
+length_in_mm(struct phys_coords mm)
+{
+	return hypot(mm.x, mm.y);
+}
+
 enum directions {
 	N  = 1 << 0,
 	NE = 1 << 1,