def Preview(self, title=None, event=None):
        """ generate Print Preview with wx Print mechanism"""
        if title is None:
            title = self.title
        if self.canvas is None:
            self.canvas = self.parent.canvas

        po1  = PrintoutWx(self.parent.canvas, title=title,
                          width=self.pwidth,   margin=self.pmargin)
        po2  = PrintoutWx(self.parent.canvas, title=title,
                          width=self.pwidth,   margin=self.pmargin)
        self.preview = wx.PrintPreview(po1, po2, self.printerData)

        if ((is_wxPhoenix and self.preview.IsOk()) or
            (not is_wxPhoenix and self.preview.Ok())):
            self.preview.SetZoom(85)
            frameInst= self.parent
            while not isinstance(frameInst, wx.Frame):
                frameInst= frameInst.GetParent()
            frame = wx.PreviewFrame(self.preview, frameInst, "Preview")
            frame.Initialize()
            frame.SetSize((850, 650))
            frame.Centre(wx.BOTH)
            frame.Show(True)
generate Print Preview with wx Print mechanism