exif_read_data
(PHP 4 >= 4.2.0, PHP 5)
exif_read_data — Reads the EXIF headers from JPEG or TIFF
Description
array exif_read_data
( string $filename
[, string $sections
[, bool $arrays
[, bool $thumbnail
]]] )
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).
Note:
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.
Parameters
-
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.
-
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.
Return Values
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.
Examples
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 />\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.
The above example will output
something similar to:
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
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