comparison base/ZoomConstraint.h @ 27:070e9e1e40ea

* Change SpectrogramLayer to use its own cache type instead of a QImage
* Some gcc-4.0 compile fixes

  */
 
 class ZoomConstraint
 {
 public:
+    virtual ~ZoomConstraint() { }
+
     enum RoundingDirection {
 	RoundDown,
 	RoundUp,
 	RoundNearest
     };