cancelToken added in upper for loop

Runtime/VectorTile.cs

@@ -349,7 +349,7 @@ namespace Wander
             List<QuadTreeNode> stack = new List<QuadTreeNode>();
 
             // For each pixel.
-            for (int y = 0;y < resolution ;y++)
+            for (int y = 0;y < resolution && !cancelToken;y++)
             {
                 for (int x = 0;x < resolution && !cancelToken ;x++)
                 {