Render themes: fallback internal resources, fix #477

vtm/src/org/oscim/backend/CanvasAdapter.java

@@ -1,6 +1,6 @@
 /*
  * Copyright 2013 Hannes Janetzek
- * Copyright 2016-2017 devemux86
+ * Copyright 2016-2018 devemux86
  * Copyright 2017 Longri
  *
  * This file is part of the OpenScienceMap project (http://www.opensciencemap.org).
@@ -166,6 +166,13 @@ public abstract class CanvasAdapter {
                 inputStream = inputStreamFromAssets(relativePathPrefix, src);
         }
 
+        // Fallback to internal resources
+        if (inputStream == null) {
+            inputStream = inputStreamFromAssets("", src);
+            if (inputStream != null)
+                log.info("internal resource: " + src);
+        }
+
         if (inputStream == null) {
             log.error("invalid resource: " + src);
             return null;