[longomatch] Fix exception drawing when the background is not set

[Andoni Morales Alastruey <amorales src gnome org>]

commit 435261420981077922682cc5aed89bcf81a8b5bc
Author: Andoni Morales Alastruey <ylatuya gmail com>
Date:   Thu Jun 19 12:47:02 2014 +0200

    Fix exception drawing when the background is not set

 LongoMatch.Drawing/Canvas.cs |   14 ++++++++------
 1 files changed, 8 insertions(+), 6 deletions(-)
---
diff --git a/LongoMatch.Drawing/Canvas.cs b/LongoMatch.Drawing/Canvas.cs
index cb530c7..d14c235 100644
--- a/LongoMatch.Drawing/Canvas.cs
+++ b/LongoMatch.Drawing/Canvas.cs
@@ -231,7 +231,7 @@ namespace LongoMatch.Drawing
                Image background;
 
                public BackgroundCanvas (IWidget widget): base (widget) {
-                       widget.SizeChangedEvent += HandleSizeChangedEvent;;
+                       widget.SizeChangedEvent += HandleSizeChangedEvent;
                }
 
                public Image Background {
@@ -254,11 +254,13 @@ namespace LongoMatch.Drawing
                
                protected override void HandleDraw (object context, Area area)
                {
-                       tk.Context = context;
-                       tk.Begin ();
-                       tk.TranslateAndScale (translation, new Point (scaleX, scaleY));
-                       tk.DrawImage (Background);
-                       tk.End ();
+                       if (Background != null) {
+                               tk.Context = context;
+                               tk.Begin ();
+                               tk.TranslateAndScale (translation, new Point (scaleX, scaleY));
+                               tk.DrawImage (Background);
+                               tk.End ();
+                       }
                        base.HandleDraw (context, area);
                }
        }