Support Requests item #2993747, was opened at 2010-04-28 14:30
Message generated for change (Tracker Item Submitted) made by mattgilbertnet
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Category: None
Group: None
Status: Open
Priority: 5
Private: No
Submitted By: Matt Gilbert (mattgilbertnet)
Assigned to: Nobody/Anonymous (nobody)
Summary: add/edit orientation tag on jpg?
Initial Comment:
How do I add/edit an orientation tag to a jpg? I've tried editting the
edit-description.php example to do this, but no luck so far. Here is my code:
$exif_orientation = 6; // 90CW, tested with in exiftool
drupal_set_message('Reading file "'.$input.'".');
$data = new PelDataWindow(file_get_contents($input));
/* The static isValid methods in PelJpeg and PelTiff will tell us in
* an efficient maner which kind of data we are dealing with. */
if (PelJpeg::isValid($data)) {
/* The data was recognized as JPEG data, so we create a new empty
* PelJpeg object which will hold it. When we want to save the
* image again, we need to know which object to same (using the
* getBytes method), so we store $jpeg as $file too. */
$jpeg = $file = new PelJpeg();
/* We then load the data from the PelDataWindow into our PelJpeg
* object. No copying of data will be done, the PelJpeg object will
* simply remember that it is to ask the PelDataWindow for data when
* required. */
$jpeg->load($data);
/* The PelJpeg object contains a number of sections, one of which
* might be our Exif data. The getExif() method is a convenient way
* of getting the right section with a minimum of fuzz. */
$exif = $jpeg->getExif();
if ($exif == null) {
/* Ups, there is no APP1 section in the JPEG file. This is where
* the Exif data should be. */
drupal_set_message('No APP1 section found, added new.');
/* In this case we simply create a new APP1 section (a PelExif
* object) and adds it to the PelJpeg object. */
$exif = new PelExif();
$jpeg->setExif($exif);
/* We then create an empty TIFF structure in the APP1 section. */
$tiff = new PelTiff();
$exif->setTiff($tiff);
} else {
/* Surprice, surprice: Exif data is really just TIFF data! So we
* extract the PelTiff object for later use. */
drupal_set_message('Found existing APP1 section.');
$tiff = $exif->getTiff();
}
} elseif (PelTiff::isValid($data)) {
/* The data was recognized as TIFF data. We prepare a PelTiff
* object to hold it, and record in $file that the PelTiff object is
* the top-most object (the one on which we will call getBytes). */
$tiff = $file = new PelTiff();
/* Now load the data. */
$tiff->load($data);
} else {
/* The data was not recognized as either JPEG or TIFF data.
* Complain loudly, dump the first 16 bytes, and exit. */
drupal_set_message('Unrecognized image format! The first 16 bytes follow:');
PelConvert::bytesToDump($data->getBytes(0, 16));
exit(1);
}
/* TIFF data has a tree structure much like a file system. There is a
* root IFD (Image File Directory) which contains a number of entries
* and maybe a link to the next IFD. The IFDs are chained together
* like this, but some of them can also contain what is known as
* sub-IFDs. For our purpose we only need the first IFD, for this is
* where the image description should be stored. */
$ifd0 = $tiff->getIfd();
if ($ifd0 == null) {
/* No IFD in the TIFF data? This probably means that the image
* didn't have any Exif information to start with, and so an empty
* PelTiff object was inserted by the code above. But this is no
* problem, we just create and inserts an empty PelIfd object. */
drupal_set_message('No IFD found, adding new.');
$ifd0 = new PelIfd(PelIfd::IFD0);
$tiff->setIfd($ifd0);
}
/* Each entry in an IFD is identified with a tag. This will load the
* ImageDescription entry if it is present. If the IFD does not
* contain such an entry, null will be returned. */
$desc = $ifd0->getEntry(PelTag::ORIENTATION);
/* We need to check if the image already had a description stored. */
if ($desc == null) {
/* The was no description in the image. */
drupal_set_message('Added new ORIENTATION entry with
"'.$exif_orientation.'"');
/* In this case we simply create a new PelEntryAscii object to hold
* the description. The constructor for PelEntryAscii needs to know
* the tag and contents of the new entry. */
$desc = new PelEntryAscii(PelTag::ORIENTATION, $exif_orientation);
/* This will insert the newly created entry with the description
* into the IFD. */
$ifd0->addEntry($desc);
} else {
/* An old description was found in the image. */
drupal_set_message('Updating ORIENTATION entry from "'.$desc->getValue().'"
to "'.$exif_orientation.'".');
/* The description is simply updated with the new description. */
$desc->setValue($exif_orientation);
}
/* At this point the image on disk has not been changed, it is only
* the object structure in memory which represent the image which has
* been altered. This structure can be converted into a string of
* bytes with the getBytes method, and saving this in the output file
* completes the script. */
drupal_set_message('Writing file "'.$input.'"');
file_put_contents($input, $file->getBytes());
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