getimagesize() 的传参是图片文件路劲
如果我只知道 tmpfile() 或 fopen() 返回的文件句柄怎么办呢
难道非要临时保存一下到硬盘上？
------解决方案--------------------
最好保存一下，如果不使用gd函数的话，那就复杂了，要自己解析图片二进制数据来得到他的原数据了。
比如这个解析png图片的。
/************************* png ****************************/
function _parsepng($file)
{
//extract info from a png file
$f=fopen($file,'rb');
if(!$f)
$this->error('can\'t open image file: '.$file);
//check signature
if(fread($f,8)!=chr(137).'png'.chr(13).chr(10).chr(26).chr(10))
$this->error('not a png file: '.$file);
//read header chunk
fread($f,4);
if(fread($f,4)!='ihdr')
$this->error('incorrect png file: '.$file);
$w=$this->_freadint($f);
$h=$this->_freadint($f);
$bpc=ord(fread($f,1));
if($bpc>8)
$this->error('16-bit depth not supported: '.$file);
$ct=ord(fread($f,1));
if($ct==0)
$colspace='devicegray';
elseif($ct==2)
$colspace='devicergb';
elseif($ct==3)
$colspace='indexed';
else
$this->error('alpha channel not supported: '.$file);
if(ord(fread($f,1))!=0)
$this->error('unknown compression method: '.$file);
if(ord(fread($f,1))!=0)
$this->error('unknown filter method: '.$file);
if(ord(fread($f,1))!=0)
$this->error('interlacing not supported: '.$file);
fread($f,4);
$parms='/decodeparms >';
//scan chunks looking for palette, transparency and image data
$pal='';
$trns='';
$data='';
do
{
$n=$this->_freadint($f);
$type=fread($f,4);
if($type=='plte')
{
//read palette
$pal=fread($f,$n);
fread($f,4);
}
elseif($type=='trns')
{
//read transparency info
$t=fread($f,$n);
if($ct==0)
$trns=array(ord(substr($t,1,1)));
elseif($ct==2)
$trns=array(ord(substr($t,1,1)),ord(substr($t,3,1)),ord(substr($t,5,1)));
else
{
$pos=strpos($t,chr(0));
if($pos!==false)
$trns=array($pos);
}
fread($f,4);
}
elseif($type=='idat')
{
//read image data block
$data.=fread($f,$n);
fread($f,4);
}
elseif($type=='iend')
break;
else
fread($f,$n+4);
}
while($n);
if($colspace=='indexed' && empty($pal))
$this->error('missing palette in '.$file);
fclose($f);
return array('w'=>$w,'h'=>$h,'cs'=>$colspace,'bpc'=>$bpc,'f'=>'flatedecode','parms'=>$parms,'pal'=>$pal,'trns'=>$trns,'data'=>$data);
}