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Dynamic image resizing in PHP
Via Darren Hoyt we found a reference to TimThumb, a quick and fast PHP script for on-the-fly image resizing. Once the script is on the server, and named timthumb.php, you can use the following reference to launch it:
<img src="/scripts/timthumb.php?src=/images/whatever.jpg&h=150&w=150&zc=1" alt="" />
Here's the source code for timthumb.php:
// http://code.google.com/p/timthumb/
// MIT License: http://www.opensource.org/licenses/mit-license.php
/* Parameters allowed: */
// w: width
// h: height
// zc: zoom crop (0 or 1)
// q: quality (default is 75 and max is 100)
// HTML example: <img src="/scripts/timthumb.php?src=/images/whatever.jpg&w=150&h=200&zc=1" alt="" />
if( !isset( $_REQUEST[ "src" ] ) ) { die( "no image specified" ); }
// clean params before use
$src = preg_replace( "/^(\.+(\/|))+/", "", $_REQUEST['src'] );
$src = preg_replace( '/^(s?f|ht)tps?:\/\/[^\/]+/i', '', $src );
$new_width = preg_replace( "/[^0-9]/", "", $_REQUEST[ 'w' ] );
$new_height = preg_replace( "/[^0-9]/", "", $_REQUEST[ 'h' ] );
$zoom_crop = preg_replace( "/[^0-9]/", "", $_REQUEST[ 'zc' ] );
if( !isset( $_REQUEST['q'] ) ) { $quality = 80; } else { $quality = preg_replace("/[^0-9]/", "", $_REQUEST['q'] ); }
// set path to cache directory (default is ./cache)
// this can be changed to a different location
$cache_dir = './cache';
// get mime type of src
$mime_type = mime_type( $src );
// check to see if this image is in the cache already
check_cache( $cache_dir, $mime_type );
// make sure that the src is gif/jpg/png
if( !valid_src_mime_type( $mime_type ) ) {
$error = "Invalid src mime type: $mime_type";
die( $error );
}
// check to see if GD function exist
if(!function_exists('imagecreatetruecolor')) {
$error = "GD Library Error: imagecreatetruecolor does not exist";
die( $error );
}
// set document root
$doc_root = $_SERVER['DOCUMENT_ROOT'];
// get path to image on file system
$src = $doc_root . '/' . $src;
if(strlen($src) && file_exists( $src ) ) {
// open the existing image
$image = open_image($mime_type, $src);
if ($image === false) { die ('Unable to open image : ' . $src ); }
// Get original width and height
$width = imagesx($image);
$height = imagesy($image);
// generate new w/h if not provided
if($new_width && !$new_height) {
$new_height = $height * ($new_width/$width);
}
elseif($new_height && !$new_width) {
$new_width = $width * ($new_height/$height);
}
elseif(!$new_width && !$new_height) {
$new_width = $width;
$new_height = $height;
}
// create a new true color image
$canvas = imagecreatetruecolor($new_width, $new_height);
if( $zoom_crop ) {
$src_x = $src_y = 0;
$src_w = $width;
$src_h = $height;
$cmp_x = $width / $new_width;
$cmp_y = $height / $new_height;
// calculate x or y coordinate and width or height of source
if ( $cmp_x > $cmp_y ) {
$src_w = round( ( $width / $cmp_x * $cmp_y ) );
$src_x = round( ( $width - ( $width / $cmp_x * $cmp_y ) ) / 2 );
}
elseif ( $cmp_y > $cmp_x ) {
$src_h = round( ( $height / $cmp_y * $cmp_x ) );
$src_y = round( ( $height - ( $height / $cmp_y * $cmp_x ) ) / 2 );
}
imagecopyresampled( $canvas, $image, 0, 0, $src_x, $src_y, $new_width, $new_height, $src_w, $src_h );
}
else {
// copy and resize part of an image with resampling
imagecopyresampled( $canvas, $image, 0, 0, 0, 0, $new_width, $new_height, $width, $height );
}
// output image to browser based on mime type
show_image( $mime_type, $canvas, $quality, $cache_dir );
// remove image from memory
ImageDestroy( $canvas );
} else {
if( strlen( $src ) ) { echo $src . ' not found.'; } else { echo 'no source specified.'; }
}
function show_image ($mime_type, $image_resized, $quality, $cache_dir) {
// check to see if we can write to the cache directory
$is_writable = 0;
$cache_file_name = $cache_dir . '/' . get_cache_file();
if( touch( $cache_file_name ) ) {
// give 666 permissions so that the developer
// can overwrite web server user
chmod( $cache_file_name, 0666 );
$is_writable = 1;
}
else {
$cache_file_name = NULL;
header('Content-type: ' . $mime_type);
}
if(stristr( $mime_type, 'gif' ) ) {
imagegif( $image_resized, $cache_file_name );
}
elseif( stristr( $mime_type, 'jpeg' ) ) {
imagejpeg( $image_resized, $cache_file_name, $quality );
}
elseif( stristr( $mime_type, 'png' ) ) {
imagepng( $image_resized, $cache_file_name, ceil( $quality / 10 ) );
}
if( $is_writable ) { show_cache_file( $cache_dir, $mime_type ); }
exit;
}
function open_image ($mime_type, $src) {
if(stristr($mime_type, 'gif')) {
$image = imagecreatefromgif($src);
}
elseif(stristr($mime_type, 'jpeg')) {
$image = imagecreatefromjpeg($src);
}
elseif(stristr($mime_type, 'png')) {
$image = imagecreatefrompng($src);
}
return $image;
}
function mime_type ($file) {
$frags = split("\.", $file);
$ext = strtolower( $frags[ count( $frags ) - 1 ] );
$types = array(
'jpg' => 'image/jpeg',
'jpeg' => 'image/jpeg',
'png' => 'image/png',
'gif' => 'image/gif',
'bmp' => 'image/bmp',
'doc' => 'application/msword',
'xls' => 'application/msword',
'xml' => 'text/xml',
'html' => 'text/html'
);
$mime_type = $types[$ext];
if(!strlen($mime_type)) { $mime_type = 'unknown'; }
return($mime_type);
}
function valid_src_mime_type ( $mime_type ) {
if( preg_match( "/jpg|jpeg|gif|png/i", $mime_type ) ) { return 1; }
return 0;
}
function check_cache ( $cache_dir, $mime_type ) {
// make sure cache dir exists
if(!file_exists($cache_dir)) {
// give 777 permissions so that developer can overwrite
// files created by web server user
mkdir( $cache_dir );
chmod( $cache_dir, 0777 );
}
show_cache_file( $cache_dir, $mime_type );
}
function show_cache_file ( $cache_dir, $mime_type ) {
$cache_file = get_cache_file();
if( file_exists( $cache_dir . '/' . $cache_file ) ) {
// check for updates
$if_modified_since = preg_replace('/;.*$/', '', $_SERVER[ "HTTP_IF_MODIFIED_SINCE" ]);
$gmdate_mod = gmdate('D, d M Y H:i:s', filemtime( $cache_dir . '/' . $cache_file ) );
if(strstr($gmdate_mod, 'GMT')) {
$gmdate_mod .= " GMT";
}
//error_log("TimThumb: $gmdate_mod == $if_modified_since");
if ( $if_modified_since == $gmdate_mod ) {
header( "HTTP/1.1 304 Not Modified" );
exit;
}
// send headers then display image
header( "Content-Type: " . $mime_type );
header( "Last-Modified: " . gmdate('D, d M Y H:i:s', filemtime( $cache_dir . '/' . $cache_file ) . " GMT" ) );
header( "Content-Length: " . filesize( $cache_dir . '/' . $cache_file ) );
header( "Cache-Control: max-age=9999, must-revalidate" );
header( "Expires: " . gmdate( "D, d M Y H:i:s", time() + 9999 ) . "GMT" );
readfile( $cache_dir . '/' . $cache_file );
exit;
}
}
function get_cache_file () {
$request_params = $_REQUEST;
$cachename = $_REQUEST['src'] . $_REQUEST['w'] . $_REQUEST['h'] . $_REQUEST['zc'] . $_REQUEST['q'];
$cache_file = md5( $cachename );
return $cache_file;
}
Topics: PHP | Submitter: admin
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