php类库给现有的图片加文字水印，代码不是很完善，欢迎大家多多指教！代码如下：

<?php    /*PHP图片加文字水印类库      QQ:3697578482 伤心的歌      该类库暂时只支持文字水印，位置为右下角，颜色随机     调用方法：     1、在需要加水印的文件顶部引入类库：        include_once 'imageClass.php';     2、声明新类：        $tpl=new image_fu;     3、给图片水印提供参数：        $tpl->img(图片路径,水印文字,字体路径,字体大小,字体角度);        比如：$tpl->img('abc.jpg','这是水印文字','ziti.ttf',30,0)    */     class image_fu{         private $image;       private $img_info;       private $img_width;       private $img_height;       private $img_im;       private $img_text;       private $img_ttf='';       private $img_new;       private $img_text_size;       private $img_jd;         function img($img='',$txt='',$ttf='',$size=12,$jiaodu=0){          if(isset($img)&&file_exists($img)){//检测图片是否存在             $this->image   =$img;              $this->img_text=$txt;             $this->img_text_size=$size;             $this->img_jd=$jiaodu;            if(file_exists($ttf)){             $this->img_ttf=$ttf;            }else{             exit('字体文件：'.$ttf.'不存在！');             }             $this->imgyesno();          }else{            exit('图片文件:'.$img.'不存在');         }        }         private function imgyesno(){            $this->img_info  =getimagesize($this->image);          $this->img_width =$this->img_info[0];//图片宽          $this->img_height=$this->img_info[1];//图片高            //检测图片类型          switch($this->img_info[2]){               case 1:$this->img_im = imagecreatefromgif($this->image);break;                case 2:$this->img_im = imagecreatefromjpeg($this->image);break;                case 3:$this->img_im = imagecreatefrompng($this->image);break;                default:exit('图片格式不支持水印');           }               $this->img_text();       }         private function img_text(){             imagealphablending($this->img_im,true);             //设定颜色            $color=imagecolorallocate($this->img_im,rand(0,255),rand(0,255),rand(0,255));            $txt_height=$this->img_text_size;            $txt_jiaodu=$this->img_jd;            $ttf_im=imagettfbbox($txt_height,$txt_jiaodu,$this->img_ttf,$this->img_text);            $w = $ttf_im[2] - $ttf_im[6];             $h = $ttf_im[3] - $ttf_im[7];             //$w = $ttf_im[7];             //$h = $ttf_im[8];               unset($ttf_im);              $txt_y     =$this->img_height-$h;            $txt_x     =$this->img_width-$w;            //$txt_y     =0;            //$txt_x     =0;              $this->img_new=@imagettftext($this->img_im,$txt_height,$txt_jiaodu,$txt_x,$txt_y,$color,$this->img_ttf,$this->img_text);             @unlink($this->image);//删除图片          switch($this->img_info[2]) {//取得背景图片的格式             case 1:imagegif($this->img_im,$this->image);break;             case 2:imagejpeg($this->img_im,$this->image);break;             case 3:imagepng($this->img_im,$this->image);break;             default: exit('水印图片失败');           }          }         //显示图片       function img_show(){echo '<img src="'.$this->image.'" border="0" alt="'.$this->img_text.'" />';}         //释放内存       private function img_nothing(){           unset($this->img_info);            imagedestroy($this->img_im);        }     }    ?>