Fatal error: Uncaught Error: Using $this when not in object context in E:\code\yqhswz\core\ThinkPHP\Library\Vendor\mpdf\config_fonts-distr-without-OTL.php:17 Stack trace: #0 {main} thrown in E:\code\yqhswz\core\ThinkPHP\Library\Vendor\mpdf\config_fonts-distr-without-OTL.php on line 17