Description
array
exif_read_data ( string filename [, string sections [, bool arrays [, bool thumbnail]]])
The exif_read_data() function reads the
EXIF headers from a JPEG or TIFF image file. It returns an associative
array where the indexes are the header names and the values
are the values associated with those headers. If no data can be returned
the result is FALSE.
filename is the name of the file to read. This
cannot be a url.
sections a comma separated lsit of sections that
need to be present in file to produce a result array.
arrays specifies whether or not each section
becomes an array. The sections FILE,
COMPUTED and THUMBNAIL allways
become arrays as they may contain values whose names are conflict
with other sections.
thumbnail whether or not to read the thumbnail
itself and not only its tagged data.
Note:
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.
Example 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>";
$exif = exif_read_data ('tests/test2.jpg',0,true);
echo "test2.jpg:<br>\n";
foreach($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.
test1.jpg:
No header data found.
test2.jpg:
FILE.FileName: test2.jpg
FILE.FileDateTime: 1015448798
FILE.FileSize: 1240
FILE.SectionsFound: COMPUTED, ANY_TAG, IFD0, THUMBNAIL, COMMENT
COMPUTED.Copyright.Photographer: Photo (c) M.Boerger
COMPUTED.Copyright.Editor: Edited by M.Boerger.
COMPUTED.html: width="1" height="1"
COMPUTED.Height: 1
COMPUTED.Width: 1
COMPUTED.IsColor: 1
COMPUTED.UserComment: Exif test image.
COMPUTED.UserCommentEncoding: ASCII
IFD0.Copyright: Photo (c) M.Boerger
IFD0.UserComment: ASCII
THUMBNAIL.JPEGInterchangeFormatLength: 523
COMMENT.0: Comment #1.
COMMENT.1: Comment #2.
COMMENT.2: Comment #3end?> |
|
Note:
When an Exif header contains a Copyright note this itself can contain
two values. As the solution is inconsitent 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.
Note:
The 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.
Note:
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 a normal HTML.
Note:
Starting from PHP 4.3 the function can read all embedded IFD
data including arrays (returned as such). Also the size of an embedded thumbnail
is returned in THUMBNAIL subarray and the function
exif_read_data() can return thumbnails in TIFF
format.
Note:
This function is only available in PHP 4 compiled using --enable-exif.
Its functionality and behaviour has changed in PHP 4.2. Earlier versions
are very unstable.
This function does not require the GD image library.
See also exif_thumbnail() and GetImageSize().
