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exif_tagname exif_imagetype

Last updated: Sat, 27 Jan 2007

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# exif_read_data

(PHP 4 >= 4.2.0, PHP 5)

exif_read_data -- Reads the EXIF headers from JPEG or TIFF

## Описание

array exif_read_data ( string filename [, string sections [, bool arrays [, bool thumbnail]]] )

exif_read_data() reads the EXIF headers from a JPEG or TIFF image file. This way you can read meta data generated by digital cameras.

Exif headers tend to be present in JPEG/TIFF images generated by digital cameras, but unfortunately each digital camera maker has a different idea of how to actually tag their images, so you can't always rely on a specific Exif header being present.

`Height` and `Width` are computed the same way getimagesize() does so their values must not be part of any header returned. Also, `html` is a height/width text string to be used inside normal HTML.

When an Exif header contains a Copyright note, this itself can contain two values. As the solution is inconsistent in the Exif 2.10 standard, the COMPUTED section will return both entries `Copyright.Photographer` and `Copyright.Editor` while the IFD0 sections contains the byte array with the NULL character that splits both entries. Or just the first entry if the datatype was wrong (normal behaviour of Exif). The COMPUTED will also contain the entry `Copyright` which is either the original copyright string, or a comma separated list of the photo and editor copyright.

The tag UserComment has the same problem as the Copyright tag. It can store two values. First the encoding used, and second the value itself. If so the IFD section only contains the encoding or a byte array. The COMPUTED section will store both in the entries `UserCommentEncoding` and `UserComment`. The entry `UserComment` is available in both cases so it should be used in preference to the value in IFD0 section.

exif_read_data() also validates EXIF data tags according to the EXIF specification (http://exif.org/Exif2-2.PDF, page 20).

> Замечание: Windows ME/XP can both wipe the Exif headers when connecting to a camera. More information available at http://www.canon.co.jp/Imaging/NOTICE/011214-e.html.

## Список параметров

`filename`

  The name of the image file being read. This cannot be an URL.

`sections`

  Is a comma separated list of sections that need to be present in file to produce a result array. If none of the requested sections could be found the return value is `FALSE`.

  FILE | FileName, FileSize, FileDateTime, SectionsFound
  COMPUTED | html, Width, Height, IsColor, and more if available. Height and Width are computed the same way getimagesize() does so their values must not be part of any header returned. Also, html is a height/width text string to be used inside normal HTML.
  ANY_TAG | Any information that has a Tag e.g. IFD0, EXIF, ...
  IFD0 | All tagged data of IFD0. In normal imagefiles this contains image size and so forth.
  THUMBNAIL | A file is supposed to contain a thumbnail if it has a second IFD. All tagged information about the embedded thumbnail is stored in this section.
  COMMENT | Comment headers of JPEG images.
  EXIF | The EXIF section is a sub section of IFD0. It contains more detailed information about an image. Most of these entries are digital camera related.

`arrays`

  Specifies whether or not each section becomes an array. The `sections` `COMPUTED`, `THUMBNAIL`, and `COMMENT` always become arrays as they may contain values whose names conflict with other sections.

`thumbnail`

  When set to `TRUE` the thumbnail itself is read. Otherwise, only the tagged data is read.

## Возвращаемые значения

It returns an associative array where the array indexes are the header names and the array values are the values associated with those headers. If no data can be returned, exif_read_data() will return `FALSE`.

## Список изменений

Версия | Описание
--- | ---
4.3.0 | Can read all embedded IFD data including arrays (returned as such). Also the size of an embedded thumbnail is returned in a `THUMBNAIL` subarray, and can return thumbnails in TIFF format. Also, there is no longer a maximum length for returned values (not until the memory limit has been reached)
4.3.0 | If PHP has mbstring support, the user comment can automatically change encoding. Also, if the user comment uses Unicode or JIS encoding this encoding will automatically be changed according to the exif ini settings in `php.ini`
4.3.0 | If the image contains any IFD0 data then COMPUTED contains the entry ByteOrderMotorola which is 0 for little-endian (intel) and 1 for big-endian (motorola) byte order. Also, COMPUTED and UserComment no longer only contain the first copyright entry if the datatype was wrong.

## Примеры

Пример 1. exif_read_data() example

`<?php
echo "test1.jpg:<br />\n";
$exif = exif_read_data('tests/test1.jpg', 'IFD0');
echo $exif===false ? "No header data found.<br />\n" : "Image contains headers<br />\n";
$exif = exif_read_data('tests/test2.jpg', 0, true);
echo "test2.jpg:<br />\n";
foreach ($exif as $key => $section) {
foreach ($section as $name => $val) {
echo "$key.$name: $val<br />\n";
}
}
?>`

The first call fails because the image has no header information.

Результатом выполнения данного примера будет что-то подобное:

`test1.jpg:
No header data found.
test2.jpg:
FILE.FileName: test2.jpg
FILE.FileDateTime: 1017666176
FILE.FileSize: 1240
FILE.FileType: 2
FILE.SectionsFound: ANY_TAG, IFD0, THUMBNAIL, COMMENT
COMPUTED.html: width="1" height="1"
COMPUTED.Height: 1
COMPUTED.Width: 1
COMPUTED.IsColor: 1
COMPUTED.ByteOrderMotorola: 1
COMPUTED.UserComment: Exif test image.
COMPUTED.UserCommentEncoding: ASCII
COMPUTED.Copyright: Photo (c) M.Boerger, Edited by M.Boerger.
COMPUTED.Copyright.Photographer: Photo (c) M.Boerger
COMPUTED.Copyright.Editor: Edited by M.Boerger.
IFD0.Copyright: Photo (c) M.Boerger
IFD0.UserComment: ASCII
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.JPEGInterchangeFormatLength: 523
COMMENT.0: Comment #1.
COMMENT.1: Comment #2.
COMMENT.2: Comment #3end
THUMBNAIL.JPEGInterchangeFormat: 134
THUMBNAIL.Thumbnail.Height: 1
THUMBNAIL.Thumbnail.Height: 1`

## Смотрите также

exif_thumbnail()
getimagesize()

add a note User Contributed Notes
exif_read_data
05-Mar-2007 11:50
`When reading EXIF information from the 'WINXP' group, you may need to change used encoding from the default "ISO-8859-15" to "UTF-8". This can be done in php.ini or in your code:
<?php
ini_set('exif.encode_unicode', 'UTF-8');
$exif = exif_read_data('TEST.JPG', 0, true);
echo $exif['WINXP']['Title'];
?>
Useful documentation about EXIF:
http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/EXIF.html
See also comments next to XPTitle and XPAuthor.`
09-Aug-2004 10:11
`I've just released the "PHP JPEG Metadata Toolkit" which allows reading, writing and displaying of EXIF information, and does not need the --enable-exif option in PHP4.
It has been tested on 466 different models of digital cameras!
It can decode the following EXIF makernotes:
Agfa, Canon, Casio, Contax, Epson, Fujifilm, Konica, Minolta, Kyocera, Nikon, Olympus, Panasonic, Pentax (Asahi), Ricoh and Sony
Additionaly it can decode IPTC, XMP, Photoshop IRB and many other types of JPEG metadata
Try it out, and download it at:
http://www.ozhiker.com/electronics/pjmt/index.html`
gimpster at gimpster dot com
17-May-2004 04:24
`I've written a library in pure PHP5 for editing EXIF tags. It deals with both reading and writing EXIF tags, and can be downloaded from http://pel.sourceforge.net/`
noway at nowaysoft dot com
23-Feb-2004 08:44
`Exif is very unstable under php4.1.2
If you have some problem, (the function didnt return anything, like a blocking call) try this:
$file = './image.jpg';
getimagesize ( $file , $info);
$exif = array();
if (isset($info)) {
foreach($info as $key => $val) {
if ($key != 'APP1') { $exif = read_exif_data($file); break; }
}
}
-- Sharp`
pekka at photography-on-the dot net
19-Nov-2003 05:50
`For reading EXIF from XMP data embedded by Adobe Photoshop CS, see http://www.photography-on-the.net/ee/beta/cs_xmp_to_exif.php`
add a note
exif_tagname exif_imagetype

Last updated: Sat, 27 Jan 2007
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