[gtk+] scrolling: interpret smooth deltas as pixels on quartz

[Jesse van den Kieboom <jessevdk src gnome org>]

commit 3fa425bb9cc3114559de09f25e57ff759bc5b531
Author: Jesse van den Kieboom <jessevdk gmail com>
Date:   Fri Sep 5 13:38:30 2014 +0200

    scrolling: interpret smooth deltas as pixels on quartz
    
    This is a temporary workaround for scrolling units being amplified
    on quartz, due to the assumption that smooth scrolling deltas are
    always in some abstract unit similar to the one from xi2.
    
    A proper solution for the situation is described in bug #736121, but
    since we are close to release, this patch solves the issue temporarily.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=736121

 gtk/gtkrange.c          |    4 ++++
 gtk/gtkscrolledwindow.c |   10 ++++++++++
 2 files changed, 14 insertions(+), 0 deletions(-)
---
diff --git a/gtk/gtkrange.c b/gtk/gtkrange.c
index 13f6887..309f43c 100644
--- a/gtk/gtkrange.c
+++ b/gtk/gtkrange.c
@@ -2806,6 +2806,10 @@ _gtk_range_get_wheel_delta (GtkRange       *range,
 
   if (gdk_event_get_scroll_deltas ((GdkEvent *) event, &dx, &dy))
     {
+#ifdef GDK_WINDOWING_QUARTZ
+      scroll_unit = 1;
+#endif
+
       if (dx != 0 &&
           gtk_orientable_get_orientation (GTK_ORIENTABLE (range)) == GTK_ORIENTATION_HORIZONTAL)
         delta = dx * scroll_unit;
diff --git a/gtk/gtkscrolledwindow.c b/gtk/gtkscrolledwindow.c
index 79f8cd8..464d14f 100644
--- a/gtk/gtkscrolledwindow.c
+++ b/gtk/gtkscrolledwindow.c
@@ -2425,7 +2425,12 @@ gtk_scrolled_window_scroll_event (GtkWidget      *widget,
 
           adj = gtk_range_get_adjustment (GTK_RANGE (priv->hscrollbar));
           page_size = gtk_adjustment_get_page_size (adj);
+
+#ifdef GDK_WINDOWING_QUARTZ
+          scroll_unit = 1;
+#else
           scroll_unit = pow (page_size, 2.0 / 3.0);
+#endif
 
           new_value = CLAMP (gtk_adjustment_get_value (adj) + delta_x * scroll_unit,
                              gtk_adjustment_get_lower (adj),
@@ -2447,7 +2452,12 @@ gtk_scrolled_window_scroll_event (GtkWidget      *widget,
 
           adj = gtk_range_get_adjustment (GTK_RANGE (priv->vscrollbar));
           page_size = gtk_adjustment_get_page_size (adj);
+
+#ifdef GDK_WINDOWING_QUARTZ
+          scroll_unit = 1;
+#else
           scroll_unit = pow (page_size, 2.0 / 3.0);
+#endif
 
           new_value = CLAMP (gtk_adjustment_get_value (adj) + delta_y * scroll_unit,
                              gtk_adjustment_get_lower (adj),