fixed printing preview to not report errors in infinite loop (bug introduced by r54133)

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@54261 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/prntbase.h

@@ -561,11 +561,15 @@ public:
     // the currently selected printer.
     virtual void DetermineScaling() = 0;
 
+protected:
+    void InvalidatePreviewBitmap();
+
 protected:
     wxPrintDialogData m_printDialogData;
     wxPreviewCanvas*  m_previewCanvas;
     wxFrame*          m_previewFrame;
     wxBitmap*         m_previewBitmap;
+    bool              m_previewFailed;
     wxPrintout*       m_previewPrintout;
     wxPrintout*       m_printPrintout;
     int               m_currentPage;