TwpViewPdf, TwpPdfPrinter, example needed (Delphi)

procedure TForm1.AddPDFClick(Sender: TObject);
var
  mem : TMemoryStream;
  meta : TMetafile;
begin
   WPPDFExport1.InMemoryMode := TRUE;
   mem := TMemoryStream.Create;
   try
     WPPDFExport1.Stream := mem;
     if PageControl1.ActivePageIndex=0 then
     begin
       WPPDFExport1.BeginDoc;
       WPPDFExport1.DrawTGraphic(0,0,0,0,Image1.Picture.Graphic);
       WPPDFExport1.EndDoc;
       mem.Position := 0;
       WPViewPDF1.LoadFromStream(mem);
     end else
     if PageControl1.ActivePageIndex=1 then
     begin
        WPPDFExport1.Source := WPRichText1;
        WPPDFExport1.Print;
        mem.Position := 0;
        WPViewPDF1.LoadFromStream(mem);
     end
     else if PageControl1.ActivePageIndex=2 then
     begin
       WPPDFExport1.BeginDoc;
       meta := FD.GetMetafile(1);
       WPPDFExport1.DrawTGraphic(0,0,0,0,meta);
       meta.Free;
       WPPDFExport1.EndDoc;
       mem.Position := 0;
       WPViewPDF1.LoadFromStream(mem);
     end
     else
     begin
       WPPDFExport1.BeginDoc;
       WPPDFExport1.StartPage(PaintBox1.Width,PaintBox1.Height,
         Screen.PixelsPerInch,Screen.PixelsPerInch,0 );
       PaintCanvas(WPPDFExport1.Canvas);
       WPPDFExport1.EndPage;
       WPPDFExport1.EndDoc;
       mem.Position := 0;
       WPViewPDF1.LoadFromStream(mem);
     end ;
   finally
     inc(demi);
     if CheckBox1.Checked then
     begin
       SaveDialog1.FileName := 'c:\DemoPDF_' + IntToStr(demi) + '.PDF';
       if SaveDialog1.Execute then
         mem.SaveToFile(SaveDialog1.FileName);   
     end;
     mem.Free;
   end;
   WPViewPDF1.Command(COMPDF_GotoLast);
   WPViewPDF1.Invalidate;
end;