X-Git-Url: http://www.aleph1.co.uk/gitweb/?p=yaffs-website;a=blobdiff_plain;f=vendor%2Flsolesen%2Fpel%2Fexamples%2Fedit-description.php;fp=vendor%2Flsolesen%2Fpel%2Fexamples%2Fedit-description.php;h=b846bcb2da0402c982c4b2b7b20ecbe6a9547b7c;hp=0000000000000000000000000000000000000000;hb=0bf8d09d2542548982e81a441b1f16e75873a04f;hpb=74df008bdbb3a11eeea356744f39b802369bda3c diff --git a/vendor/lsolesen/pel/examples/edit-description.php b/vendor/lsolesen/pel/examples/edit-description.php new file mode 100644 index 000000000..b846bcb2d --- /dev/null +++ b/vendor/lsolesen/pel/examples/edit-description.php @@ -0,0 +1,247 @@ +#!/usr/bin/php + [desc]', $prog); + println('Optional arguments:'); + println(' -d turn debug output on.'); + println(' desc the new description.'); + println('Mandatory arguments:'); + println(' input the input file, a JPEG or TIFF image.'); + println(' output the output file for the changed image.'); + exit(1); +} + +/* Any remaining arguments are considered the new description. */ +$description = implode(' ', $argv); + +/* + * We typically need lots of RAM to parse TIFF images since they tend + * to be big and uncompressed. + */ +ini_set('memory_limit', '32M'); + +/* + * The input file is now read into a PelDataWindow object. At this + * point we do not know if the file stores JPEG or TIFF data, so + * instead of using one of the loadFile methods on PelJpeg or PelTiff + * we store the data in a PelDataWindow. + */ +println('Reading file "%s".', $input); +$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. + */ + println('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. + */ + println('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. + */ + println('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. + */ + println('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 = $ifd0->getEntry(PelTag::IMAGE_DESCRIPTION); + +/* We need to check if the image already had a description stored. */ +if ($desc == null) { + /* The was no description in the image. */ + println('Added new IMAGE_DESCRIPTION entry with "%s".', $description); + + /* + * 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::IMAGE_DESCRIPTION, $description); + + /* + * 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. */ + println('Updating IMAGE_DESCRIPTION entry from "%s" to "%s".', $desc->getValue(), $description); + + /* The description is simply updated with the new description. */ + $desc->setValue($description); +} + +/* + * 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. + */ +println('Writing file "%s".', $output); +$file->saveFile($output);