Add demonstration of layer extent setting to reprojection example

examples/reprojection.js

@@ -178,6 +178,13 @@ function updateViewProjection() {
     extent: newProjExtent || undefined
   });
   map.setView(newView);
+
+  // Example how to prevent double occurence of map by limiting layer extent
+  if (newProj == ol.proj.get('EPSG:3857')) {
+    layers['bng'].setExtent([-1057216, 6405988, 404315, 8759696]);
+  } else {
+    layers['bng'].setExtent(undefined);
+  }
 }