[gnome-documents] thumb-nav: handle GDK_SCROLL_SMOOTH events

[Cosimo Cecchi <cosimoc src gnome org>]

commit 66cd8f34401bbd0be79029f1a5d8cceaaa6c665b
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Thu Mar 8 16:04:39 2012 -0500

    thumb-nav: handle GDK_SCROLL_SMOOTH events
    
    Emulate a scroll instead of crashing.

 src/lib/gd-thumb-nav.c |   15 +++++++++++++++
 1 files changed, 15 insertions(+), 0 deletions(-)
---
diff --git a/src/lib/gd-thumb-nav.c b/src/lib/gd-thumb-nav.c
index dce5b95..afed2be 100644
--- a/src/lib/gd-thumb-nav.c
+++ b/src/lib/gd-thumb-nav.c
@@ -71,6 +71,7 @@ gd_thumb_nav_scroll_event (GtkWidget *widget, GdkEventScroll *event, gpointer us
 	GdThumbNav *nav = GD_THUMB_NAV (user_data);
 	gint inc = GD_THUMB_NAV_SCROLL_INC * 3;
 	gdouble upper, page_size, value;
+	gdouble delta_x, delta_y;
 
 	switch (event->direction) {
 	case GDK_SCROLL_UP:
@@ -82,6 +83,20 @@ gd_thumb_nav_scroll_event (GtkWidget *widget, GdkEventScroll *event, gpointer us
 	case GDK_SCROLL_RIGHT:
 		break;
 
+        case GDK_SCROLL_SMOOTH:
+		gdk_event_get_scroll_deltas ((const GdkEvent *) event,
+					     &delta_x, &delta_y);
+
+		if (delta_x == 0) {
+			/* we only moved in the y direction, look at which direction */
+			if (delta_y < 0)
+				inc *= -1;
+		} else if (delta_x < 0) {
+			/* if we moved in the x direction too, ignore the y */
+			inc *= -1;
+		}
+
+		break;
 	default:
 		g_assert_not_reached ();
 		return FALSE;