(PHP 5)
image_type_to_extension — 取得图像类型的文件后缀
$imagetype
[, bool $include_dot = TRUE
] )根据给定的常量 IMAGETYPE_XXX 返回后缀名。
imagetype
IMAGETYPE_XXX 系列常量之一。
include_dot
是否在后缀名前加一个点。默认是 TRUE。
根据指定的图像类型返回对应的后缀名。
Example #1 image_type_to_extension() 例子
<?php
// 创建图像实例
$im = imagecreatetruecolor(100, 100);
// 保存图像
imagepng($im, './test' . image_type_to_extension(IMAGETYPE_PNG));
imagedestroy($im);
?>
Note:
此函数不需要 GD 图象库。
mike dot carper at gmail dot com (2012-08-31 19:50:18)
Here is a way to get the extension of an image without GD installed by using getimagesize() http://php.net/getimagesize. Note that using the predefined constants like IMAGETYPE_JPEG only get loaded if GD is enabled; see http://php.net/image.constants.
<?php
$file = 'http://static.php.net/www.php.net/images/php.gif';
echo get_image_extension($file);
// Returns '.gif'
/**
* Given an image filename, get the file extension.
*
* @param $filename
* This parameter specifies the file you wish to retrieve information about.
* It can reference a local file or (configuration permitting) a remote file
* using one of the supported streams.
* @param $include_dot
* Whether to prepend a dot to the extension or not. Default to TRUE.
* @param $shorter_extensions
* Whether to use a shorter extension or not. Default to TRUE.
* @return
* A string with the extension corresponding to the given image filename, or
* FALSE on failure.
*/
function get_image_extension($filename, $include_dot = true, $shorter_extensions = true) {
$image_info = @getimagesize($filename);
if (!$image_info || empty($image_info[2])) {
return false;
}
if (!function_exists('image_type_to_extension')) {
/**
* Given an image filename, get the file extension.
*
* @param $imagetype
* One of the IMAGETYPE_XXX constants.
* @param $include_dot
* Whether to prepend a dot to the extension or not. Default to TRUE.
* @param $shorter_extensions
* Whether to use a shorter extension or not. Default to TRUE.
* @return
* A string with the extension corresponding to the given image type, or
* FALSE on failure.
*/
function image_type_to_extensiona ($imagetype, $include_dot = true) {
// Note we do not use the IMAGETYPE_XXX constants as these will not be
// defined if GD is not enabled.
$extensions = array(
1 => 'gif',
2 => 'jpeg',
3 => 'png',
4 => 'swf',
5 => 'psd',
6 => 'bmp',
7 => 'tiff',
8 => 'tiff',
9 => 'jpc',
10 => 'jp2',
11 => 'jpf',
12 => 'jb2',
13 => 'swc',
14 => 'aiff',
15 => 'wbmp',
16 => 'xbm',
);
// We are expecting an integer between 1 and 16.
$imagetype = (int)$imagetype;
if (!$imagetype || !isset($extensions[$imagetype])) {
return false;
}
return ($include_dot ? '.' : '') . $extensions[$imagetype];
}
}
$extension = image_type_to_extension($image_info[2], $include_dot);
if (!$extension) {
return false;
}
if ($shorter_extensions) {
$replacements = array(
'jpeg' => 'jpg',
'tiff' => 'tif',
);
$extension = strtr($extension, $replacements);
}
return $extension;
}
?>
bimal at sanjaal dot com (2012-02-06 10:06:17)
<?php
/**
* Returns a COMMON extension with a dot
*/
function gd_extension($full_path_to_image='')
{
$extension = 'null';
if($image_type = exif_imagetype($full_path_to_image))
{
$extension = image_type_to_extension($image_type, false);
}
$known_replacements = array(
'jpeg' => 'jpg',
'tiff' => 'tif',
);
$extension = '.'.str_replace(array_keys($known_replacements), array_values($known_replacements), $extension);
return $extension;
}
# Testing
$images = glob('*');
foreach($images as $i => $image)
{
$extension = gd_extension($image);
echo "\r\n", $image, ': ', $extension;
}
?>
Sometimes, the extension is not as I expected, until I wrote this piece.
mew at world dot org (2007-12-07 23:26:14)
There is no need to over complicated folks.
<?php
if ( !function_exists('image_type_to_extension') ) {
function image_type_to_extension ($type, $dot = true)
{
$e = array ( 1 => 'gif', 'jpeg', 'png', 'swf', 'psd', 'bmp'
'tiff', 'tiff', 'jpc', 'jp2', 'jpf', 'jb2', 'swc',
'aiff', 'wbmp', 'xbm');
// We are expecting an integer.
$type = (int)$type;
if (!$type) {
trigger_error( '...come up with an error here...', E_USER_NOTICE );
return null;
}
if ( !isset($e[$type]) ) {
trigger_error( '...come up with an error here...' E_USER_NOTICE );
return null;
}
return ($dot ? '.' : '') . $e[$type];
}
}
if ( !function_exists('image_type_to_mime_type') ) {
function image_type_to_mime_type ($type)
{
$m = array ( 1 => 'image/gif', 'image/jpeg', 'image/png',
'application/x-shockwave-flash', 'image/psd', 'image/bmp',
'image/tiff', 'image/tiff', 'application/octet-stream',
'image/jp2', 'application/octet-stream', 'application/octet-stream',
'application/x-shockwave-flash', 'image/iff', 'image/vnd.wap.wbmp', 'image/xbm');
// We are expecting an integer.
$type = (int)$type;
if (!$type) {
trigger_error( '...come up with an error here...', E_USER_NOTICE );
return null;
}
if ( !isset($m[$type]) ) {
trigger_error( '...come up with an error here...' E_USER_NOTICE );
return null;
}
return $m[$type];
}
}
?>
Chris (2007-08-25 19:17:18)
- Function was added in PHP 5.2, not PHP 5 (you would assume this means 5.0)
- Function returns .jpeg, not .jpg
Ian Paul Short chukdocsAtHotmailDotCom (2006-09-28 21:10:52)
To: mail at spybreak dot de
I noted your solution was for mime_type_to_extension which is flawed because the MIME types to extensions are not unique. See my example to consider what I have observed.
This function performs image type or mime type to extension. With limitation it will not attempt to handle duplicated MIME types. NOT DEFINITIVE!
<?php
if(!function_exists('image_type_to_extension')){
$extension;
function image_type_or_mime_type_to_extension($image_type, $include_dot) {
define ("INVALID_IMAGETYPE", '');
$extension = INVALID_IMAGETYPE; /// Default return value for invalid input
$image_type_identifiers = array ( ### These values correspond to the IMAGETYPE constants
array (IMAGETYPE_GIF => 'gif', "mime_type" => 'image/gif'), ### 1 = GIF
array (IMAGETYPE_JPEG => 'jpg', "mime_type" => 'image/jpeg'), ### 2 = JPG
array (IMAGETYPE_PNG => 'png', "mime_type" => 'image/png'), ### 3 = PNG
array (IMAGETYPE_SWF => 'swf', "mime_type" => 'application/x-shockwave-flash'), ### 4 = SWF // A. Duplicated MIME type
array (IMAGETYPE_PSD => 'psd', "mime_type" => 'image/psd'), ### 5 = PSD
array (IMAGETYPE_BMP => 'bmp', "mime_type" => 'image/bmp'), ### 6 = BMP
array (IMAGETYPE_TIFF_II => 'tiff', "mime_type" => 'image/tiff'), ### 7 = TIFF (intel byte order)
array (IMAGETYPE_TIFF_MM => 'tiff', "mime_type" => 'image/tiff'), ### 8 = TIFF (motorola byte order)
array (IMAGETYPE_JPC => 'jpc', "mime_type" => 'application/octet-stream'), ### 9 = JPC // B. Duplicated MIME type
array (IMAGETYPE_JP2 => 'jp2', "mime_type" => 'image/jp2'), ### 10 = JP2
array (IMAGETYPE_JPX => 'jpf', "mime_type" => 'application/octet-stream'), ### 11 = JPX // B. Duplicated MIME type
array (IMAGETYPE_JB2 => 'jb2', "mime_type" => 'application/octet-stream'), ### 12 = JB2 // B. Duplicated MIME type
array (IMAGETYPE_SWC => 'swc', "mime_type" => 'application/x-shockwave-flash'), ### 13 = SWC // A. Duplicated MIME type
array (IMAGETYPE_IFF => 'aiff', "mime_type" => 'image/iff'), ### 14 = IFF
array (IMAGETYPE_WBMP => 'wbmp', "mime_type" => 'image/vnd.wap.wbmp'), ### 15 = WBMP
array (IMAGETYPE_XBM => 'xbm', "mime_type" => 'image/xbm') ### 16 = XBM
);
if((is_int($image_type)) AND (IMAGETYPE_GIF <= $image_type) AND (IMAGETYPE_XBM >= $image_type)){
$extension = $image_type_identifiers[$image_type-1]; // -1 because $image_type_identifiers array starts at [0]
$extension = $extension[$image_type];
}
elseif(is_string($image_type) AND (($image_type != 'application/x-shockwave-flash') OR ($image_type != 'application/octet-stream'))){
$extension = match_mime_type_to_extension($image_type, $image_type_identifiers);
}
else
{
$extension = INVALID_IMAGETYPE;
}
if(is_bool($include_dot)){
if((false != $include_dot) AND (INVALID_IMAGETYPE != $extension)){
$extension = '.' . $extension;
}
}
else
{
$extension = INVALID_IMAGETYPE;
}
return $extension;
}
}
function match_mime_type_to_extension($image_type, $image_type_identifiers){
// Return from loop on a match
foreach($image_type_identifiers as $_key_outer_loop => $_val_outer_loop){
foreach($_val_outer_loop as $_key => $_val){
if(is_int ($_key)){ // Keep record of extension for mime check
$extension = $_val;
}
if($_key == 'mime_type'){
if($_val === $image_type){ // Found match no need to continue looping
return $extension; ### Return
}
}
}
}
// Compared all values without match
return $extension = INVALID_IMAGETYPE;
}
$extension = image_type_or_mime_type_to_extension($image_type, $include_dot);
return $extension;
}
?>
Ian Paul Short chukdocsAtHotmailDotCom (2006-09-28 19:55:10)
2006-09-29
A few notes about some contributions on this page.
1. It seemed to me that on the face it of all of the offerings to emulate "image_type_to_extension" function fell short of the mark in one way or another (See my comments below). That's why I wrote my own and submitted to this page below. In respect of my work any comments, bugs noted or improvements would be gratefully received.
2. Avoid using the Switch statement in an unconventional method to "Break" (I note the use of the return statement!). Also even if it does nothing at the inception of our code - Still put in the default case (It lets others realise that a default is not required or at worst forgotton.
3. In an environment that is under your control the risk of an error by determining the content by its extension or MIME type may seem an attractive solution to a problem. However, in the real world there's no guarantee that a MIME type or file extension is correct for it's associated file.
Consider using functions to get the image type:
getimagesize or (This is available without GD)
exif_imagetype
4. There's more to coding than just putting something together to do a job!!! But whatever is done is worthwhile - Hence expletives have no place in this forum!!
5. The idea from "oridan at hotmail dot com" is a very slick idea. I will be taking a closer look at this for my own project.
Ian Paul Short (2006-09-28 16:40:42)
2006-09-29 Author: Ian Paul Short (chukdocs at hotmail dot com)
For reasons I have yet to determine the function “image_type_to_extension” is not available to both PHP 5.1.4 on my local host running under Windows XP or on my remote host running under Linux. Has anyone else had this problem? If so kindly post your findings here please.
In the meantime I needed a workaround and with many thanks to the previous contributors on this page - I took bits and pieces developed the following function to emulate the function image_type_to_extension:
if(!function_exists('image_type_to_extension')){ ### Include this for graceful tranisition to using
### PHP's equivalent function when it's available in the box
function image_type_to_extension($image_type, $include_dot){
// Assign definitions and intialise variables
define ("INVALID_IMAGETYPE", ''); // Empty string
$extension = INVALID_IMAGETYPE; // Return this (empty string) if "$image_type or $include_dot" do not contain legal values
if((is_int($image_type)) AND (is_bool($include_dot)) AND (IMAGETYPE_GIF <= $image_type) AND (IMAGETYPE_XBM >= $image_type)){ // Check input data are legal
$image_type_extension = array ( ### These integer values correspond to the the respective IMAGETYPE constants
IMAGETYPE_GIF => 'gif', ### 1 = GIF
IMAGETYPE_JPEG => 'jpg', ### 2 = JPG
IMAGETYPE_PNG => 'png', ### 3 = PNG
IMAGETYPE_SWF => 'swf', ### 4 = SWF
IMAGETYPE_PSD => 'psd', ### 5 = PSD
IMAGETYPE_BMP => 'bmp', ### 6 = BMP
IMAGETYPE_TIFF_II => 'tiff', ### 7 = TIFF (intel byte order)
IMAGETYPE_TIFF_MM => 'tiff', ### 8 = TIFF (motorola byte order)
IMAGETYPE_JPC => 'jpc', ### 9 = JPC
IMAGETYPE_JP2 => 'jp2', ### 10 = JP2
IMAGETYPE_JPX => 'jpf', ### 11 = JPX Yes! jpf extension is correct for JPX image type
IMAGETYPE_JB2 => 'jb2', ### 12 = JB2
IMAGETYPE_SWC => 'swc', ### 13 = SWC
IMAGETYPE_IFF => 'aiff', ### 14 = IFF
IMAGETYPE_WBMP => 'wbmp', ### 15 = WBMP
IMAGETYPE_XBM => 'xbm' ### 16 = XBM
);
$extension = $image_type_extension[$image_type]; // Get extension by using array as a look up table using $image_type as key
if($include_dot != false) $extension = '.' . $extension; // If $include_dot is true prefix a dot to extension
}
### Limitation - No user friendly error handler
/*
else
{
### Put your error handler here
}
*/
return $extension;
}
}
discerer at _REMOVETHIS_yahoo dot co dot uk (2006-01-08 07:23:25)
at aleksandrs note about mime checking
i really hope that piece of code isn't used as some kind of security check for uploading (excluding those which have no value in the switch-case ie), as the mime type in uploading could be very easily changed
and btw if you want to get the extension why not just use substr to get all the text after the last dot in the filename to be really sure that the file is really what the mime says?
this could be done easily with
<?php
$filename = "roflhax.pwnage.jpeg";
if (($pos = strrpos($filename, ".")) === FALSE)
echo "Error - file doesn't have a dot... weird.";
else {
$extension = substr($filename, $pos + 1);
echo $extension; // will echo "jpeg"
}
?>
(or you could use pathinfo() or a regex :))
aleksandrs dot bogdanovs at gmail dot com (2005-12-23 05:44:45)
When I was writing a script for my photo website, it was necessary to write such function, which can get the extension of uploaded file (image), so the function is:
<?php
function get_extension($imagetype)
{
if(empty($imagetype)) return false;
switch($imagetype)
{
case 'image/bmp': return '.bmp';
case 'image/cis-cod': return '.cod';
case 'image/gif': return '.gif';
case 'image/ief': return '.ief';
case 'image/jpeg': return '.jpg';
case 'image/pipeg': return '.jfif';
case 'image/tiff': return '.tif';
case 'image/x-cmu-raster': return '.ras';
case 'image/x-cmx': return '.cmx';
case 'image/x-icon': return '.ico';
case 'image/x-portable-anymap': return '.pnm';
case 'image/x-portable-bitmap': return '.pbm';
case 'image/x-portable-graymap': return '.pgm';
case 'image/x-portable-pixmap': return '.ppm';
case 'image/x-rgb': return '.rgb';
case 'image/x-xbitmap': return '.xbm';
case 'image/x-xpixmap': return '.xpm';
case 'image/x-xwindowdump': return '.xwd';
case 'image/png': return '.png';
case 'image/x-jps': return '.jps';
case 'image/x-freehand': return '.fh';
default: return false;
}
}
?>
It's useful for those, who upload files on server.
oridan at hotmail dot com (2005-11-11 10:06:38)
i used your code in the following to open different types of files depending on their 'type' (or rather, extension). the eval simply creates
<?
// make sure you initialize $filename as the path to the image you want to load/create
list(,,$type) = getimagesize($filename);
$type = image_type_to_extension($type);
eval("global \$filename; \$source = imagecreatefrom$type(\$filename);");
global $source;
?>
$source is then the var you can play with. saved me a big switch statement calling different "imagecreatefromjpg"/"imagecreatefromgif" functions just to do the one simple task.... open an image of varying types.
robe at amd dot co dot at (2005-09-28 12:31:08)
neil: your version fails to make sense for me
spybreak.de guy:
a) you left out BMP
b) you fucked up the order of the extension in the mid of the listing. if this was changed in the getimagesize function during php versions, I'm sorry. Otherwise: WHY?!
c) the include_dot stuff is the worst abuse of function arguments I've ever seen. Shame on you.
Here's a unfucked, working version:
<?
if(!function_exists('image_type_to_extension'))
{
function image_type_to_extension($imagetype)
{
if(empty($imagetype)) return false;
switch($imagetype)
{
case IMAGETYPE_GIF : return 'gif';
case IMAGETYPE_JPEG : return 'jpg';
case IMAGETYPE_PNG : return 'png';
case IMAGETYPE_SWF : return 'swf';
case IMAGETYPE_PSD : return 'psd';
case IMAGETYPE_BMP : return 'bmp';
case IMAGETYPE_TIFF_II : return 'tiff';
case IMAGETYPE_TIFF_MM : return 'tiff';
case IMAGETYPE_JPC : return 'jpc';
case IMAGETYPE_JP2 : return 'jp2';
case IMAGETYPE_JPX : return 'jpf';
case IMAGETYPE_JB2 : return 'jb2';
case IMAGETYPE_SWC : return 'swc';
case IMAGETYPE_IFF : return 'aiff';
case IMAGETYPE_WBMP : return 'wbmp';
case IMAGETYPE_XBM : return 'xbm';
default : return false;
}
}
}
?>
neil at g4s dot org (2005-09-21 22:24:40)
refining the homebrew method a little further, i wound up with this version. note that i had to change the case statements from previous version to include call to image_type_to_mime_type()
<?php
public static function imageTypeToExtension($imageType, $includeDot = false) {
$dot = $includeDot ? '.' : '';
$ext = false;
if(!empty($imageType)) {
switch($imageType) {
case image_type_to_mime_type(IMAGETYPE_GIF) : $ext = $dot.'gif'; break;
case image_type_to_mime_type(IMAGETYPE_JPEG) : $ext = $dot.'jpg'; break;
case image_type_to_mime_type(IMAGETYPE_PNG) : $ext = $dot.'png'; break;
case image_type_to_mime_type(IMAGETYPE_SWF) : $ext = $dot.'swf'; break;
case image_type_to_mime_type(IMAGETYPE_PSD) : $ext = $dot.'psd'; break;
case image_type_to_mime_type(IMAGETYPE_WBMP) : $ext = $dot.'wbmp'; break;
case image_type_to_mime_type(IMAGETYPE_XBM) : $ext = $dot.'xbm'; break;
case image_type_to_mime_type(IMAGETYPE_TIFF_II) : $ext = $dot.'tiff'; break;
case image_type_to_mime_type(IMAGETYPE_TIFF_MM) : $ext = $dot.'tiff'; break;
case image_type_to_mime_type(IMAGETYPE_IFF) : $ext = $dot.'aiff'; break;
case image_type_to_mime_type(IMAGETYPE_JB2) : $ext = $dot.'jb2'; break;
case image_type_to_mime_type(IMAGETYPE_JPC) : $ext = $dot.'jpc'; break;
case image_type_to_mime_type(IMAGETYPE_JP2) : $ext = $dot.'jp2'; break;
case image_type_to_mime_type(IMAGETYPE_JPX) : $ext = $dot.'jpf'; break;
case image_type_to_mime_type(IMAGETYPE_SWC) : $ext = $dot.'swc'; break;
}
}
return $ext;
}
?>
(2005-04-19 05:11:26)
Just an improvement/bugfix for the function below:
<?php
$dot = $include_dot ? $dot.'' : '';
//surely what was meant is....:
$dot = $include_dot ? '.' : '';
?>
Because otherwise $dot always will be empty.....
mail at spybreak dot de (2004-08-14 18:12:23)
In case your PHP doesn't have this function, you can use this:
<?
if(!function_exists('image_type_to_extension'))
{
function image_type_to_extension($imagetype,$include_dot=true)
{
if(empty($imagetype)) return false;
$dot = $include_dot ? $dot.'' : '';
switch($imagetype)
{
case IMAGETYPE_GIF : return $dot.'gif';
case IMAGETYPE_JPEG : return $dot.'jpg';
case IMAGETYPE_PNG : return $dot.'png';
case IMAGETYPE_SWF : return $dot.'swf';
case IMAGETYPE_PSD : return $dot.'psd';
case IMAGETYPE_WBMP : return $dot.'wbmp';
case IMAGETYPE_XBM : return $dot.'xbm';
case IMAGETYPE_TIFF_II : return $dot.'tiff';
case IMAGETYPE_TIFF_MM : return $dot.'tiff';
case IMAGETYPE_IFF : return $dot.'aiff';
case IMAGETYPE_JB2 : return $dot.'jb2';
case IMAGETYPE_JPC : return $dot.'jpc';
case IMAGETYPE_JP2 : return $dot.'jp2';
case IMAGETYPE_JPX : return $dot.'jpf';
case IMAGETYPE_SWC : return $dot.'swc';
default : return false;
}
}
}
?>