var
  oQuickPdf: TQuickPDF;
  iUnlock: Integer;
  iPageHeight, iPageWidth: Double;
  iPrimaryDoc, iSecondaryDoc, iCapturedPageID, iCount, iPrimaryPageCount: Integer;
  sTargetFileName, sDocumentOverlayFile, sDocumentPdfFile: string;
begin

  oQuickPdf := TQuickPDF.Create;
  try
    iUnlock := oQuickPdf.UnlockKey('');

    if iUnlock = 1 then
    begin
      sDocumentPdfFile := DM.GetTempFile('.pdf');
      sDocumentOverlayFile := DM.GetTempFile('.pdf');
      sTargetFileName := DM.GetTempFile('.pdf');
      try
        oQuickPdf.LoadFromFile('c:\users\olav\desktop\Invoice DE.pdf');

        iPrimaryDoc := oQuickPdf.SelectedDocument();
        iPrimaryPageCount := oQuickPdf.PageCount;

        oQuickPdf.LoadFromFile('c:\users\olav\desktop\Overlay.pdf');

        iSecondaryDoc := oQuickPdf.SelectedDocument();

        oQuickPdf.SelectDocument(iPrimaryDoc);

        oQuickPdf.MergeDocument(iSecondaryDoc);

        iPageHeight := oQuickPdf.PageHeight();
        iPageWidth := oQuickPdf.PageWidth();

        iCapturedPageID := oQuickPdf.CapturePage(oQuickPdf.PageCount);

        oQuickPdf.SelectDocument(iPrimaryDoc);

        for iCount := 1 to iPrimaryPageCount do begin
          oQuickPdf.SelectPage(iCount);
          oQuickPdf.SetOrigin(1);
          oQuickPdf.DrawCapturedPage(iCapturedPageID, 0, 0, iPageWidth, iPageHeight);
        end;

        oQuickPdf.SaveToFile(sTargetFileName);
        ShellExecute(Application.Handle, 'open', PAnsiChar(sTargetFileName), '', '', SW_NORMAL);
      finally
  	 //delete files etc.
      end;

    end else
    begin
      ShowMessage('Invalid license key');
    end;
  finally
    oQuickPdf.Free;
  end;
end;