gtk/scrolledwindow: Check for overshoot setting up kinetic scroll helpers

We may have situations where velocity is 0/0, but are overshooting. Places where
this happens are mouse wheels, and continuous scroll that ended up still before
finish. In this situation we also want to run the animation for overshoot, so
check for the corresponding axes to also set up the kinetic scroll helper.

Closes: https://gitlab.gnome.org/GNOME/gtk/-/issues/4784

diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 518e0a44125a791bb8e80549147c440fcaf9b311..116fc9645a73303a0e8bdc381b716e144369a462 100644 (file)
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -3337,6 +3337,7 @@ gtk_scrolled_window_start_deceleration (GtkScrolledWindow *scrolled_window)
   GdkFrameClock *frame_clock;
   gint64 current_time;
   double elapsed;
+  int overshoot_x, overshoot_y;
 
   g_return_if_fail (priv->deceleration_id == 0);
 
@@ -3346,6 +3347,8 @@ gtk_scrolled_window_start_deceleration (GtkScrolledWindow *scrolled_window)
   elapsed = (current_time - priv->last_deceleration_time) / (double)G_TIME_SPAN_SECOND;
   priv->last_deceleration_time = current_time;
 
+  _gtk_scrolled_window_get_overshoot (scrolled_window, &overshoot_x, &overshoot_y);
+
   if (may_hscroll (scrolled_window))
     {
       double lower,upper;
@@ -3354,7 +3357,7 @@ gtk_scrolled_window_start_deceleration (GtkScrolledWindow *scrolled_window)
       gtk_scrolled_window_accumulate_velocity (&priv->hscrolling, elapsed, &priv->x_velocity);
       g_clear_pointer (&priv->hscrolling, gtk_kinetic_scrolling_free);
 
-      if (priv->x_velocity != 0)
+      if (priv->x_velocity != 0 || overshoot_x != 0)
         {
           hadjustment = gtk_scrollbar_get_adjustment (GTK_SCROLLBAR (priv->hscrollbar));
           lower = gtk_adjustment_get_lower (hadjustment);
@@ -3381,7 +3384,7 @@ gtk_scrolled_window_start_deceleration (GtkScrolledWindow *scrolled_window)
       gtk_scrolled_window_accumulate_velocity (&priv->vscrolling, elapsed, &priv->y_velocity);
       g_clear_pointer (&priv->vscrolling, gtk_kinetic_scrolling_free);
 
-      if (priv->y_velocity != 0)
+      if (priv->y_velocity != 0 || overshoot_y != 0)
         {
           vadjustment = gtk_scrollbar_get_adjustment (GTK_SCROLLBAR (priv->vscrollbar));
           lower = gtk_adjustment_get_lower(vadjustment);