PHP生成缩略图的一个方法类（转）

//使用如下类就可以生成图片缩略图
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
var $dstimg;
//临时创建的图象
var $im;

function resizeimage($img, $wid, $hei,$c,$dstpath)
{
$this->srcimg = $img;
$this->resize_width = $wid;
$this->resize_height = $hei;
$this->cut = $c;
//图片的类型
$this->type = strtolower(substr(strrchr($this->srcimg,"."),1));
//初始化图象
$this->initi_img();
//目标图象地址
$this -> dst_img($dstpath);
//--
$this->width = imagesx($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($dstpath)
{
$full_length  = strlen($this->srcimg);

$type_length  = strlen($this->type);
$name_length  = $full_length-$type_length;

$name         = substr($this->srcimg,0,$name_length-1);
$this->dstimg = $dstpath;

//echo $this->dstimg;
}
}

//就只用下面的一句话,就能生成缩略图,其中,源文件和缩略图地址可以相同,200,100分别代表宽和高,第4个参数表示是否截图
$resizeimage = new resizeimage($save_path.$file_name, "185", "130", "0",$save_path."c_".$file_name);