php背景图片生成代码

/** 
        *@author:yangtao 
        *@date:2016-08-12 
        *@content: 背景水印 
        */ 
       public function getbgwatermark(){
     
     
           $imgWidth = 150; 
           $imgHeight = 150; 
           $img = imagecreatetruecolor($imgWidth, $imgHeight); 
           $bgcolor = imagecolorallocate($img,255,255,255); 
           imagefill($img, 0, 0, $bgcolor); 
     
           $text = imagecreatetruecolor($imgWidth, $imgHeight); 
           imagefill($text, 0, 0, $bgcolor); 
           $font_size = 10; 
           $font_name = VENDOR_PATH."topthink/think-captcha/assets/ttfs/1.ttf"; 
           $ucode = $this->getUserinfo('userCode'); 
           if($ucode=="") $ucode = "测试文字"; 
           $font_color = imagecolorallocate($img, mt_rand(100,200), mt_rand(100,200), mt_rand(100,200)); 
           imagettftext($text, $font_size, 50, 10,90, $font_color, $font_name, $ucode); 
     
           imagecopymerge($img,$text,0,0,0,0,$imgWidth,$imgHeight,20); 
     
           header('content-type:image/png'); 
           imagepng($img); 
           imagedestroy($img); 
       }