[gtk: 4/7] gtkrange: Add scroll unit handling

[Carlos Garnacho <carlosg src gnome org>]

commit f9e2c106bc24865fae7f5b6c73f0a533bc298b88
Author: panoplie <59100-panoplie users noreply gitlab gnome org>
Date:   Mon Feb 28 21:45:06 2022 +0100

    gtkrange: Add scroll unit handling

 gtk/gtkrange.c | 20 +++++++++++---------
 1 file changed, 11 insertions(+), 9 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index c3c270e6c3..f185ab6763 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2202,25 +2202,27 @@ gtk_range_scroll_controller_scroll (GtkEventControllerScroll *scroll,
                                     GtkRange                 *range)
 {
   GtkRangePrivate *priv = gtk_range_get_instance_private (range);
-  double scroll_unit, delta;
+  double delta;
   gboolean handled;
   GtkOrientation move_orientation;
-
-#ifdef GDK_WINDOWING_MACOS
-  scroll_unit = 1;
-#else
-  scroll_unit = gtk_adjustment_get_page_increment (priv->adjustment);
-#endif
+  GdkScrollUnit scroll_unit;
 
   if (priv->orientation == GTK_ORIENTATION_HORIZONTAL && dx != 0)
     {
       move_orientation = GTK_ORIENTATION_HORIZONTAL;
-      delta = dx * scroll_unit;
+      delta = dx;
     }
   else
     {
       move_orientation = GTK_ORIENTATION_VERTICAL;
-      delta = dy * scroll_unit;
+      delta = dy;
+    }
+
+  scroll_unit = gtk_event_controller_scroll_get_unit (scroll);
+
+  if (scroll_unit == GDK_SCROLL_UNIT_WHEEL)
+    {
+      delta *= gtk_adjustment_get_page_increment (priv->adjustment);
     }
 
   if (delta != 0 && should_invert_move (range, move_orientation))