ScaleBar disappears sometimes fix by Erik Duisters, fixes openscience…

…map#155

vtm/src/org/oscim/scalebar/MapScaleBarLayer.java

@@ -28,7 +28,7 @@ public MapScaleBarLayer(Map map, MapScaleBar mapScaleBar) {
         super(map);
         this.mapScaleBar = mapScaleBar;
 
-        mRenderer = bitmapRenderer = new BitmapRenderer();
+        mRenderer = bitmapRenderer = new MapScaleBarRenderer();
         bitmapRenderer.setBitmap(mapScaleBar.mapScaleBitmap, mapScaleBar.mapScaleBitmap.getWidth(), mapScaleBar.mapScaleBitmap.getHeight());
     }
 

vtm/src/org/oscim/scalebar/MapScaleBarRenderer.java

@@ -0,0 +1,27 @@
+/*
+ * Copyright 2016 Erik Duisters
+ *
+ * This program is free software: you can redistribute it and/or modify it under the
+ * terms of the GNU Lesser General Public License as published by the Free Software
+ * Foundation, either version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but WITHOUT ANY
+ * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A
+ * PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+package org.oscim.scalebar;
+
+import org.oscim.renderer.BitmapRenderer;
+import org.oscim.renderer.GLState;
+import org.oscim.renderer.GLViewport;
+
+public class MapScaleBarRenderer extends BitmapRenderer {
+    @Override
+    public synchronized void render(GLViewport v) {
+        GLState.test(false, false);
+        super.render(v);
+    }
+}