[geary] Make zooming conversation view work with smooth scrolling

[Robert Schroll <rschroll src gnome org>]

commit ef984d8eca1cdbfc123016bb8e86ccd361e20c81
Author: Robert Schroll <rschroll gmail com>
Date:   Wed Jun 11 01:08:04 2014 -0400

    Make zooming conversation view work with smooth scrolling
    
    Often, we get smooth scrolling events on WebViews, but the zooming code
    looks only for non-smooth scroll events.  This handles both.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=731500

 .../conversation-viewer/conversation-web-view.vala |   12 ++++++++++--
 1 files changed, 10 insertions(+), 2 deletions(-)
---
diff --git a/src/client/conversation-viewer/conversation-web-view.vala 
b/src/client/conversation-viewer/conversation-web-view.vala
index deab9b9..96d1808 100644
--- a/src/client/conversation-viewer/conversation-web-view.vala
+++ b/src/client/conversation-viewer/conversation-web-view.vala
@@ -57,10 +57,18 @@ public class ConversationWebView : StylishWebView {
     
     public override bool scroll_event(Gdk.EventScroll event) {
         if ((event.state & Gdk.ModifierType.CONTROL_MASK) != 0) {
-            if (event.direction == Gdk.ScrollDirection.UP) {
+            double dir = 0;
+            if (event.direction == Gdk.ScrollDirection.UP)
+                dir = -1;
+            else if (event.direction == Gdk.ScrollDirection.DOWN)
+                dir = 1;
+            else if (event.direction == Gdk.ScrollDirection.SMOOTH)
+                dir = event.delta_y;
+            
+            if (dir < 0) {
                 zoom_in();
                 return true;
-            } else if (event.direction == Gdk.ScrollDirection.DOWN) {
+            } else if (dir > 0) {
                 zoom_out();
                 return true;
             }