21段救命PHP代码(14)

        '\1<a href="http://\2">\2</a>', $text);
        $text = eregi_replace('([_.0-9a-z-]+@([0-9a-z][0-9a-z-]+.)+[a-z]{2,3})',
        '<a href="mailto:\1">\1</a>', $text);   
        
        return $text;
        }
　20. PHP调整图像尺寸
　　创建图像缩略图需要许多时间，此代码将有助于了解缩略图的逻辑。
        /**********************
        *@filename - path to the image
        *@tmpname - temporary path to thumbnail
        *@xmax - max width
        *@ymax - max height
        */
        function resize_image($filename, $tmpname, $xmax, $ymax)
        {
                $ext = explode(".", $filename);
                $ext = $ext[count($ext)-1];    
        
                if($ext == "jpg" || $ext == "jpeg")
                        $im = imagecreatefromjpeg($tmpname);
                elseif($ext == "png")
                        $im = imagecreatefrompng($tmpname);
                elseif($ext == "gif")
                        $im = imagecreatefromgif($tmpname);    
        
                $x = imagesx($im);
                $y = imagesy($im);    
        
                if($x <= $xmax && $y <= $ymax)