该怎么去调用这个类？
srcimg = $img;
    $this->corner = $corner;
       $this->resize_width = $wid;
       $this->resize_height = $hei;
       $this->cut = $c;
    $this->corner_radius = $corner_radius;
    $this->angle = $angle;
       //图片的类型
       $this->type = substr(strrchr($this->srcimg,.),1);
       //初始化图象
       $this->initi_img();
       //目标图象地址
       $this -> dst_img();
       //--
       $this->width = imagesx($this->im);
       $this->height = imagesy($this->im);
       //生成图象
       $this->newimg();
       imagedestroy ($this->im);
   }
   function newimg()
   {
       //改变后的图象的比例
       $resize_ratio = ($this->resize_width)/($this->resize_height);
       //实际图象的比例
       $ratio = ($this->width)/($this->height);
       if(($this->cut)==1)
       //裁图
       {
           if($ratio>=$resize_ratio)
           //高度优先
           {
               $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
               imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width,$this->resize_height, (($this->height)*$resize_ratio), $this->height);
      $tmp = $this->rounded_corner($newimg,$this->resize_width);
               imagepng ($tmp,$this->dstimg);
           }
           if($ratio           //宽度优先
           {
               $newimg = imagecreatetruecolor($this->resize_width,$this->resize_height);
               imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, $this->resize_height, $this->width, (($this->width)/$resize_ratio));
      $tmp = $this->rounded_corner($newimg);
               imagepng ($tmp,$this->dstimg);
           }
       }
       else
       //不裁图
       {
           if($ratio>=$resize_ratio)
           {
               $newimg = imagecreatetruecolor($this->resize_width,($this->resize_width)/$ratio);
               imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, $this->resize_width, ($this->resize_width)/$ratio, $this->width, $this->height);
               imagejpeg ($newimg,$this->dstimg);
           }