当我习惯于使用PHPExcel将文件保存为PDF时出错

我在项目中使用PHPExcel库，当我习惯于保存文件格式（xls/xlsx）时，它的工作很好。但我需要将文件保存为PDF格式，我找到了一些例子，但没有一个对我有效。这是我用来生成pdf格式文件的代码

<?php
error_reporting(E_ALL);
ini_set('include_path', ini_get('include_path').';../Classes/');
include 'PHPExcel/Classes/PHPExcel/IOFactory.php';
    $inputFileName = 'file.xls';
        try {
               $inputFileType = PHPExcel_IOFactory::identify($inputFileName);
               $objReader = PHPExcel_IOFactory::createReader($inputFileType);
               $objPHPExcel = $objReader->load($inputFileName);
        } catch(Exception $e) {
               die('Error loading file "'.pathinfo($inputFileName,PATHINFO_BASENAME).'": '.$e->getMessage());
        }
$objPHPExcel->setActiveSheetIndex(0);
$row = $objPHPExcel->getActiveSheet()->getHighestRow()+1;
        $sheet = $objPHPExcel->getSheet(0); 
        $highestRow = $sheet->getHighestRow(); 
        $highestColumn = $sheet->getHighestColumn();
$objWriter = PHPExcel_IOFactory::createWriter($objPHPExcel, 'PDF');
$objSheet = $objPHPExcel->getActiveSheet();
$objPHPExcel->getActiveSheet()->SetCellValue('A1', 'test test');
$objWriter->save('test100.pdf');
?>

这是浏览器显示给我的

( ! ) Fatal error: Uncaught exception 'PHPExcel_Writer_Exception' with message 'PDF Rendering library has not been defined.' in C:'wamp'www'projet'PHPExcel'Classes'PHPExcel'Writer'PDF.php on line 56

我做错了什么