procedure TForm2.Button1Click(Sender: TObject);
        var
              param            : IMxDrawResbuf;
              ret               : IMxDrawResbuf;
        begin
              // 创建参数对象
              param :=  CoMxDrawResbuf.Create();
               // 文件路径,-10是参数的DXF组码，取-10控件自动确定DXF组码
              param.AddString('c:test.jpg');
              // jpg的宽度
              param.AddLong(1200);
              // jpg的高度
              param.AddLong(500);
              // jpg的背景色,    16777215 = 0xFFFFFF,是白色
              param.AddLong(16777215);
              // 调用自定义函数 Mx_SaveJpgFileEx
              ret := IMxDrawResbuf(MxDrawX1.CallEx('Mx_SaveJpgFileEx',param));
              if ret.AtString(0) = 'Ok' then
              begin
                showmessage('保存成功到C:test.jpg');
              end;
        end;