php 图片处理方法 缩略和剪切

<?
//图片缩放类

class resizeimage
{
   //图片类型
   var $type;
   //实际宽度
   var $width;
   //实际高度
   var $height;
   //改变后的宽度
   var $resize_width;
   //改变后的高度
   var $resize_height;
   //是否裁图
   var $cut;
   //源图象
   var $srcimg;
   //目标图象地址[separator]
   var $dstimg;
   //临时创建的图象
   var $im;

function resizeimage($img, $wid, $hei,$c)
   {
       $this->srcimg = $img;
       $this->resize_width = $wid;
       $this->resize_height = $hei;
       $this->cut = $c;
       //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), $this->height);
               ImageJpeg ($newimg,$this->dstimg);
           }
           if($ratio<$resize_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)/$resize_ratio));
               ImageJpeg ($newimg,$this->dstimg);
           }
       }
       else
       //不裁图
       {
           if($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,$this->dstimg);
           }
           if($ratio<$resize_ratio)
           {
               $newimg = imagecreatetruecolor(($this->resize_height)*$ratio,$this->resize_height);
               imagecopyresampled($newimg, $this->im, 0, 0, 0, 0, ($this->resize_height)*$ratio, $this->resize_height, $this->width, $this->height);
               ImageJpeg ($newimg,$this->dstimg);
           }
       }
   }
   //初始化图象
   function initi_img()
   {
       if($this->type=="jpg")
       {
           $this->im = imagecreatefromjpeg($this->srcimg);
       }
       if($this->type=="gif")
       {
           $this->im = imagecreatefromgif($this->srcimg);
       }
       if($this->type=="png")
       {
           $this->im = imagecreatefrompng($this->srcimg);
       }
   }
   //图象目标地址
   function dst_img()
   {
       $full_length = strlen($this->srcimg);
       $type_length = strlen($this->type);
       $name_length = $full_length-$type_length;
       $name         = substr($this->srcimg,0,$name_length-1);
       $this->dstimg = $name."_s.".$this->type;
   }
}

$resizeimage = new resizeimage("test.jpg", "360", "360", "0"); //生成新的图片为 test_s.jpg
?>
<img src=\'#\'" border="0">