Thumbnail Script

<?php
/* 
	thumb.php v0.3
	______________________________________________________________________ 
	Creates a thumbnailed image based on info passed to it via $_GET. 
	
	Images are cached on the server, so server processing overhead is only 
	needed for the first time the script runs on a particular image.
	______________________________________________________________________
	Requires:
		GD Library
	______________________________________________________________________
	Copyright: 
		(C) 2003 Chris Tomlinson. [email protected]
		http://mightystuff.net
		
		This library is free software; you can redistribute it and/or
		modify it under the terms of the GNU Lesser General Public
		License as published by the Free Software Foundation; either
		version 2.1 of the License, or (at your option) any later version.
		
		This library is distributed in the hope that it will be useful,
		but WITHOUT ANY WARRANTY; without even the implied warranty of
		MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
		Lesser General Public License for more details.
	
		http://www.gnu.org/copyleft/lesser.txt
	______________________________________________________________________
	Configuration:
		set $thumb_size to be a default maximum width/height if not passed via get
		set $no_image to be an image to be used when GIF files are passed to the script (The GD library no longer supports gif images)
		set $site_config['path_thumbnail'] to be a write-permissable folder on your server relative to the DOCUMENT_ROOT for storing images so they cache on the server.
		set $quality to be a value 0-100 for the resulting thumbnail jpeg quality
	______________________________________________________________________	
	Usage:
		<img src="thumb.php?file=FILE&size=SIZE">
		
		Where:
		FILE	=	the file to retrieve
		SIZE	=	the maximum size of the thumbnail in pixels
	______________________________________________________________________
*/
//script configuration
$thumb_size = 128; //all thumbnails are this maximum width or height if not specified via get
$no_image	= '/preview/images/no_image.png';	// used if no image could be found, or a gif image is specified
$site_config['path_thumbnail']='/images/thumbnails/';	//where to cache thumbnails on the server, relative to the DOCUMENT_ROOT
$quality	= 70;
//define size of image (maximum width or height)- if specified via get.
if ($_GET["size"]<>0) {
	$thumb_size=$_GET["size"];
}
//determine filesystem - *nix or windows - and set document_root. if the file is outside of the web server root path, the document_root is ignored and the absolute path of the image is used instead. 
if (substr_count(strtolower($_ENV['OS']), "windows")>0)
{
	//w32 filesystem
	$site_config['document_root'] = str_replace(str_replace("/","\",$_SERVER["SCRIPT_NAME"]),"",$_SERVER["PATH_TRANSLATED"]);
	if (file_exists(str_replace("/","\",$_GET['file'])))
	{
		$filename=str_replace("/","\",$_GET['file']);
	} else {
		$filename=$site_config['document_root']."\".str_replace("/","\",$_GET['file']);
	}
} else {
	//linux filesystem
	$site_config['document_root'] = $_SERVER['DOCUMENT_ROOT'];
	if (file_exists($_GET["file"]))
	{
		$filename=$_GET["file"];
	} else {
		$filename=$site_config['document_root'].'/'.$_GET["file"];
	}
}
$no_image=$site_config['document_root'].$no_image;

if (file_exists($site_config['document_root'].$site_config['path_thumbnail'].md5($filename.$thumb_size).'.jpeg'))
{
	Header('Content-type: image/jpeg');
	Header("Expires: Mon, 26 Jul 2030 05:00:00 GMT");    
	Header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size).'.jpeg'));

	echo (join('', file( $site_config['document_root'].$site_config['path_thumbnail'].md5($filename.$thumb_size).'.jpeg' )));

	exit; //no need to create thumbnail - it already exists in the cache
}

//determine php and gd versions
$ver=intval(str_replace(".","",phpversion()));
if ($ver>=430)
{
	$gd_version=gd_info();
}


$filename=str_replace("'","'",$filename);

//define the right function for the right image types
$image_type_arr=getimagesize($filename);
$image_type=$image_type_arr[2];

switch ($image_type)
{
	case 2:	// JPG
		$image = ImageCreateFromJPEG ($filename); 
		break;
	case 3: // PNG
		$image = ImageCreateFromPNG ($filename); 
		break;
	case 1:	// GIF - replace file with a 'no image' png
	default:
		$image = ImageCreateFromPNG ($no_image); 
		break;
}

//define size of original image	
$image_width = imagesx($image);
$image_height = imagesy($image);

//define size of the thumbnail	
$thumb_width = $thumb_size; //$image_width/$resize_factor;
$factor = $image_width/$thumb_size;
$thumb_height = $image_height / $factor; //($image_width.$width_factor); //$resize_factor;
if ($thumb_height>$thumb_size)
{
	$thumb_height = $thumb_size; //$image_width/$resize_factor;
	$factor = $image_height/$thumb_size;
	$thumb_width = $image_width / $factor; //($image_width.$width_factor); //$resize_factor;
}

//define size if sizex and sizey given
if ($_GET["sizex"]<>0) {
	$thumb_width=$_GET["sizex"];
	$thumb_height=$_GET["sizey"];
}

$memsize=filesize($filename);

//create the thumbnail
if ($image_width<2000)	//no point in resampling images larger than 2000 pixels wide - too much server processing overhead - a resize is more economical
{
	if (substr_count(strtolower($gd_version['GD Version']), "2.")>0)
	{
		//GD 2.0 
		$thumbnail = ImageCreateTrueColor($thumb_width, $thumb_height);
		imagecopyresampled($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);
	} else {
		//GD 1.0 
		$thumbnail = imagecreate($thumb_width, $thumb_height);
		imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);			
	}	
} else {
	if (substr_count(strtolower($gd_version['GD Version']), "2.")>0)
	{
		//GD 2.0 
		$thumbnail = ImageCreateTrueColor($thumb_width, $thumb_height);
		imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);
	} else {
		//GD 1.0 
		$thumbnail = imagecreate($thumb_width, $thumb_height);
		imagecopyresized($thumbnail, $image, 0, 0, 0, 0, $thumb_width, $thumb_height, $image_width, $image_height);
	}
}

//create thumbnail in the cache because it doesn't exist yet.
Header('Content-type: image/jpeg');
Header("Expires: Mon, 26 Jul 2030 05:00:00 GMT");    
Header('Content-Disposition: inline; filename='.str_replace('/','',md5($filename.$thumb_size).'.jpeg'));

imagejpeg($thumbnail,$site_config['document_root'].$site_config['path_thumbnail'].md5($filename.$thumb_size).'.jpeg',$quality);
echo (join('', file( $site_config['document_root'].$site_config['path_thumbnail'].md5($filename.$thumb_size).'.jpeg')));		

//clear memory
imagedestroy ($image);
imagedestroy ($thumbnail);

?>