--- a/Framework/Layers/ILayerSource.h	Wed May 24 12:42:08 2017 +0200
+++ b/Framework/Layers/ILayerSource.h	Wed May 24 21:13:29 2017 +0200
@@ -22,7 +22,7 @@
 #pragma once
 
 #include "ILayerRenderer.h"
-#include "../Toolbox/SliceGeometry.h"
+#include "../Toolbox/Slice.h"
 
 namespace OrthancStone
 {
@@ -40,22 +40,24 @@
       // answer to "GetExtent()"
       virtual void NotifyGeometryReady(ILayerSource& source) = 0;
       
+      virtual void NotifyGeometryError(ILayerSource& source) = 0;
+      
       // Triggered if the extent or the content of the volume has changed
       virtual void NotifySourceChange(ILayerSource& source) = 0;
 
-      // Triggered if some slice in the source volume has changed
+      // Triggered if the content of some slice in the source volume has changed
       virtual void NotifySliceChange(ILayerSource& source,
-                                     const SliceGeometry& slice) = 0;
+                                     const Slice& slice) = 0;
 
       // The layer must be deleted by the observer. "layer" will never
       // be "NULL", otherwise "NotifyLayerError()" would have been
       // called.
       virtual void NotifyLayerReady(ILayerRenderer *layer,
                                     ILayerSource& source,
-                                    const SliceGeometry& viewportSlice) = 0;
+                                    const Slice& slice) = 0;
 
       virtual void NotifyLayerError(ILayerSource& source,
-                                    const SliceGeometry& viewportSlice) = 0;
+                                    const SliceGeometry& slice) = 0;
     };
     
     virtual ~ILayerSource()