Expose whether CanvasElement is visible

simgear/canvas/elements/CanvasElement.cxx

@@ -210,6 +210,12 @@ namespace canvas
     return true;
   }
 
+  //----------------------------------------------------------------------------
+  bool Element::isVisible() const
+  {
+    return _transform->getNodeMask() != 0;
+  }
+
   //----------------------------------------------------------------------------
   osg::ref_ptr<osg::MatrixTransform> Element::getMatrixTransform()
   {

simgear/canvas/elements/CanvasElement.hxx

@@ -82,6 +82,11 @@ namespace canvas
       virtual bool hitBound( const osg::Vec2f& pos,
                              const osg::Vec2f& local_pos ) const;
 
+      /**
+       * Get whether the element is visible or hidden (Can be changed with
+       * setting property "visible" accordingly).
+       */
+      bool isVisible() const;
 
       osg::ref_ptr<osg::MatrixTransform> getMatrixTransform();