Render themes: fallback internal resources, fix #477

docs/Changelog.md

@@ -4,6 +4,7 @@
 
 - S3DB layer [#475](https://github.com/mapsforge/vtm/pull/475)
 - OpenMapTiles GeoJSON vector tiles [#385](https://github.com/mapsforge/vtm/issues/385)
+- Render theme fallback internal resources [#477](https://github.com/mapsforge/vtm/issues/477)
 - Many other minor improvements and bug fixes
 - [Solved issues](https://github.com/mapsforge/vtm/issues?q=is%3Aclosed+milestone%3A0.10.0)
 
@@ -113,6 +114,7 @@
 - Tile size based on scale factor [#183](https://github.com/mapsforge/vtm/issues/183)
 - libGDX layer gestures [#151](https://github.com/mapsforge/vtm/issues/151)
 - Render theme area tessellation option [#37](https://github.com/mapsforge/vtm/issues/37)
+- Render theme resources optional location prefixes [#66](https://github.com/mapsforge/vtm/issues/66)
 - Graphics API platform enhancements [#92](https://github.com/mapsforge/vtm/issues/92)
 - GeoPoint & BoundingBox improvements [#201](https://github.com/mapsforge/vtm/issues/201) [#200](https://github.com/mapsforge/vtm/issues/200)
 - vtm-jts module [#53](https://github.com/mapsforge/vtm/issues/53)

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;