private static Drawable getEmojiMarker(final Resources res, final int emoji, final boolean applyScaling) {
        final Drawable markerBg = new ScalableDrawable(ViewUtils.getDrawable(R.drawable.marker_empty, true), getWaypointScalingFactor(applyScaling));
        final InsetsBuilder markerBuilder = new InsetsBuilder(res, markerBg.getIntrinsicWidth(), markerBg.getIntrinsicHeight(), true);
        markerBuilder.withInset(new InsetBuilder(markerBg));
        markerBuilder.withInset(new InsetBuilder(getScaledEmojiDrawable(res, emoji, "iconMarkerForWaypoint", applyScaling)));
        return buildLayerDrawable(markerBuilder, 2, 2);
    }
Create a LayerDrawable showing the caches difficulty and terrain rating. If the connector doesn't support D/T show a "-" instead, if the info is missing (not loaded) a "?"
@param res           Resources bundle
@param difficulty    Difficulty rating
@param terrain       Terrain rating
@return              LayerDrawable composed of round background and foreground showing the ratings
main/src/main/java/cgeo/geocaching/utils/MapMarkerUtils.java