Notify user less intrusively about overflow when previewing HTML printouts.

We used to show a modal dialog if the page didn't fit horizontally but this
was too intrusive when the user was just previewing the output and not really
printing it. Moreover, the question of the message box ("Print" or "Cancel")
simply didn't make sense in this case.

Fix both problems by not showing this dialog at all when previewing. Instead,
notify the user with a much less intrusive info bar in the preview window.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@64214 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/html/htmprint.h

@@ -176,15 +176,17 @@ public:
 private:
     // this function is called by the base class OnPreparePrinting()
     // implementation and by default checks whether the document fits into
-    // pageArea horizontally and warns the user if it does not, giving him
-    // the possibility to cancel printing in this case
+    // pageArea horizontally and warns the user if it does not and, if we're
+    // going to print and not just to preview the document, giving him the
+    // possibility to cancel printing
     //
     // you may override it to either suppress this check if truncation of the
     // HTML being printed is acceptable or, on the contrary, add more checks to
     // it, e.g. for the fit in the vertical direction if the document should
     // always appear on a single page
     //
-    // return true if printing should go ahead or false to cancel it
+    // return true if printing should go ahead or false to cancel it (the
+    // return value is ignored when previewing)
     virtual bool CheckFit(const wxSize& pageArea, const wxSize& docArea) const;
 
     void RenderPage(wxDC *dc, int page);