gestureswipe: Count last event when calculating velocity

The last event, matching lifting the finger/releasing the mouse button,
is important when there's a large delay between it and the previous events,
as in when performing a movement, stopping, then releasing fingers as
opposed to doing a swipe.

If this event is skipped, doing this will result in kinetic deceleration
matching the previous finger movement, while the expected behavior would
be no deceleration.

See also 97f540622abca60b54d5a8141d6f05bf791ffdb8 for a similar fix in
GtkEventControllerScroll.

1 files changed, 15 insertions, 5 deletions

diff --git a/gtk/gtkgestureswipe.c b/gtk/gtkgestureswipe.c
index bf84eb5a3e..91bf19d999 100644
--- a/gtk/gtkgestureswipe.c
+++ b/gtk/gtkgestureswipe.c
@@ -126,17 +126,16 @@ _gtk_gesture_swipe_clear_backlog (GtkGestureSwipe *gesture,
 }
 
 static void
-gtk_gesture_swipe_update (GtkGesture       *gesture,
-                          GdkEventSequence *sequence)
+gtk_gesture_swipe_append_event (GtkGestureSwipe  *swipe,
+                                GdkEventSequence *sequence)
 {
-  GtkGestureSwipe *swipe = GTK_GESTURE_SWIPE (gesture);
   GtkGestureSwipePrivate *priv;
   EventData new;
   gdouble x, y;
 
   priv = gtk_gesture_swipe_get_instance_private (swipe);
-  _gtk_gesture_get_last_update_time (gesture, sequence, &new.evtime);
-  gtk_gesture_get_point (gesture, sequence, &x, &y);
+  _gtk_gesture_get_last_update_time (GTK_GESTURE (swipe), sequence, &new.evtime);
+  gtk_gesture_get_point (GTK_GESTURE (swipe), sequence, &x, &y);
 
   new.point.x = x;
   new.point.y = y;
@@ -146,6 +145,15 @@ gtk_gesture_swipe_update (GtkGesture       *gesture,
 }
 
 static void
+gtk_gesture_swipe_update (GtkGesture       *gesture,
+                          GdkEventSequence *sequence)
+{
+  GtkGestureSwipe *swipe = GTK_GESTURE_SWIPE (gesture);
+
+  gtk_gesture_swipe_append_event (swipe, sequence);
+}
+
+static void
 _gtk_gesture_swipe_calculate_velocity (GtkGestureSwipe *gesture,
                                        gdouble         *velocity_x,
                                        gdouble         *velocity_y)
@@ -198,6 +206,8 @@ gtk_gesture_swipe_end (GtkGesture       *gesture,
   if (gtk_gesture_is_active (gesture))
     return;
 
+  gtk_gesture_swipe_append_event (swipe, sequence);
+
   priv = gtk_gesture_swipe_get_instance_private (swipe);
   _gtk_gesture_swipe_calculate_velocity (swipe, &velocity_x, &velocity_y);
   g_signal_emit (gesture, signals[SWIPE], 0, velocity_x, velocity_y);