+ void OnUpdateNextButton(wxUpdateUIEvent& event)
+ { event.Enable(IsNextEnabled()); }
+ void OnUpdatePreviousButton(wxUpdateUIEvent& event)
+ { event.Enable(IsPreviousEnabled()); }
+ void OnUpdateFirstButton(wxUpdateUIEvent& event)
+ { event.Enable(IsFirstEnabled()); }
+ void OnUpdateLastButton(wxUpdateUIEvent& event)
+ { event.Enable(IsLastEnabled()); }
+ void OnUpdateZoomInButton(wxUpdateUIEvent& event)
+ { event.Enable(IsZoomInEnabled()); }
+ void OnUpdateZoomOutButton(wxUpdateUIEvent& event)
+ { event.Enable(IsZoomOutEnabled()); }
+
+ // These methods are not private because they are called by wxPreviewCanvas.
+ void DoZoomIn();
+ void DoZoomOut();
+