From 6be0f108b43523c3394cb684cdc938a98b4f9f4a Mon Sep 17 00:00:00 2001 From: Christian Hergert Date: Sun, 24 Apr 2016 02:41:26 -0700 Subject: kineticscrolling: avoid stutter at tail of kinetic deceleration When decelerating the kinetic scroll, we can get into a position where it looks like we are stuttering. This happens because the amount we move is so little that it takes multiple frames to make forward progress by one pixel. This prevents that by detecting when we have reached the slow stutter of the deceleration and simply stops the deceleration phase immediately. https://bugzilla.gnome.org/show_bug.cgi?id=765493 --- gtk/gtkkineticscrolling.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/gtk/gtkkineticscrolling.c b/gtk/gtkkineticscrolling.c index c33faee9c3..29bf085674 100644 --- a/gtk/gtkkineticscrolling.c +++ b/gtk/gtkkineticscrolling.c @@ -152,6 +152,8 @@ gtk_kinetic_scrolling_tick (GtkKineticScrolling *data, { case GTK_KINETIC_SCROLLING_PHASE_DECELERATING: { + gdouble last_position = data->position; + gdouble last_time = data->t; gdouble exp_part; data->t += time_delta; @@ -168,7 +170,8 @@ gtk_kinetic_scrolling_tick (GtkKineticScrolling *data, { gtk_kinetic_scrolling_init_overshoot(data, data->upper, data->position, data->velocity); } - else if (fabs(data->velocity) < 1) + else if (fabs(data->velocity) < 1 || + (last_time != 0.0 && fabs(data->position - last_position) < 1)) { data->phase = GTK_KINETIC_SCROLLING_PHASE_FINISHED; data->position = round(data->position); -- cgit v1.2.1