diff layer/Layer.h @ 947:e53a87a5efb2

Allow layers to be loaded without models if their layer class explicitly says it's OK (otherwise default template won't load, as it has an empty waveform layer)

--- a/layer/Layer.h	Mon Apr 20 09:12:17 2015 +0100
+++ b/layer/Layer.h	Mon Apr 20 10:10:26 2015 +0100
@@ -62,7 +62,7 @@
     Model *getModel() {
 	return const_cast<Model *>(const_cast<const Layer *>(this)->getModel());
     }
-
+    
     /**
      * Return a zoom constraint object defining the supported zoom
      * levels for this layer.  If this returns zero, the layer will
@@ -518,6 +518,13 @@
      */
     virtual RangeMapper *getNewVerticalZoomRangeMapper() const { return 0; }
 
+    /**
+     * Return true if this layer type can function without a model
+     * being set. If false (the default), the layer will not be loaded
+     * from a session if its model cannot be found.
+     */
+    virtual bool canExistWithoutModel() const { return false; }
+
 public slots:
     void showLayer(View *, bool show);