# HG changeset patch
# User Chris Cannam
# Date 1429524048 -3600
# Node ID e3c7da3d896e722b0ade45a422a97971de68558b
# Parent  8bf05426d950651fec612b3297632395171648c7# Parent  e53a87a5efb2fcf90ca9d97cfe0592b53226d002
Merge from default branch

diff -r 8bf05426d950 -r e3c7da3d896e layer/Layer.h
--- a/layer/Layer.h	Mon Apr 20 11:00:39 2015 +0100
+++ b/layer/Layer.h	Mon Apr 20 11:00:48 2015 +0100
@@ -63,7 +63,7 @@
     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
@@ -520,6 +520,13 @@
      */
     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(LayerGeometryProvider *, bool show);
 
diff -r 8bf05426d950 -r e3c7da3d896e layer/TimeRulerLayer.h
--- a/layer/TimeRulerLayer.h	Mon Apr 20 11:00:39 2015 +0100
+++ b/layer/TimeRulerLayer.h	Mon Apr 20 11:00:48 2015 +0100
@@ -60,6 +60,8 @@
 
     void setProperties(const QXmlAttributes &attributes);
 
+    virtual bool canExistWithoutModel() const { return true; }
+
 protected:
     Model *m_model;
     LabelHeight m_labelHeight;
diff -r 8bf05426d950 -r e3c7da3d896e layer/WaveformLayer.h
--- a/layer/WaveformLayer.h	Mon Apr 20 11:00:39 2015 +0100
+++ b/layer/WaveformLayer.h	Mon Apr 20 11:00:48 2015 +0100
@@ -202,6 +202,8 @@
     virtual int getCurrentVerticalZoomStep() const;
     virtual void setVerticalZoomStep(int);
 
+    virtual bool canExistWithoutModel() const { return true; }
+
 protected:
     int dBscale(double sample, int m) const;