diff --git a/SketchWidget.py b/SketchWidget.py
index bd9f2d3..a5aaf43 100644
--- a/SketchWidget.py
+++ b/SketchWidget.py
@@ -213,11 +213,20 @@ class SketchWidget:
             self.view_center = (self.view_center[0] - this_pt[0] + start_pt[0],
                     self.view_center[1] - this_pt[1] + start_pt[1])
             self.panning_start = (event.x, self.size[1] - event.y)
-            self.widget.queue_draw_area(0, 0,
-                    int(self.size[0]), int(self.size[1]))
+            self.redraw()
 
     def scroll_event(self, widget, event, data = None):
         if event.direction == gtk.gdk.SCROLL_UP:
-            print 'scroll up at (%d, %d)' % (event.x, event.y)
+            self.view_center = self.screenPtToPt((event.x,
+                self.size[1] - event.y))
+            self.view_width /= 1.2
+            self.redraw()
         elif event.direction == gtk.gdk.SCROLL_DOWN:
-            print 'scroll down at (%d, %d)' % (event.x, event.y)
+            self.view_center = self.screenPtToPt((event.x,
+                self.size[1] - event.y))
+            self.view_width *= 1.2
+            self.redraw()
+
+    def redraw(self):
+        self.widget.queue_draw_area(0, 0,
+                int(self.size[0]), int(self.size[1]))