"Beck, Jonas" <[EMAIL PROTECTED]> writes: Hi Jonas
> i have to convert about 40000 pictures using a php skript - part of
> that conversion is the addition/modification of the EXIF data of all
> that images. PEL seemed perfect for the job, especially as the JPEG
> MetadataToolkit is not able to create new EXIF data so easily.
Wow, that is a lot of photos! I'm glad to hear that PEL is being
pushed to its limits.
> If an image has no EXIF data yet I want to add some - to some extend
> that works as expected, but if I try to add those winXP EXIF tags,
> PEL wont read them. They are written to the header - as I can view
> them with the JPEG MetadataToolkit, but windows wont show them. If I
> write them in with windows, PEL wont show them.
>
> if use:
>
> $title = $ifd0->getEntry(PelTag::XP_TITLE);
>
> echo $title;
>
> if ($title == null) {
> echo "Adding new XP_TITLE entry with value 'XP_TITLE'.<br>";
> $title = new PelEntryWindowsString(PelTag::XP_TITLE, "CATDog");
> $ifd0->addEntry($title);
> } else {
> echo "Updating XP_TITLE entry from '".$title->getValue()."' to
> 'XP_TITLE'<br>";
> $title->setValue("XP_TITLE");
> }
>
> to check for an XP_TITLE, and create one if there isnt any.
That should be the correct way to do it.
> But there is never an XP_TITLE tag - even if windows shows it and I
> can read it in the EXIF data. PEL just wont get it.
Okay... As I don't use Windows, these XP_* tags have been only very
lightly tested. And I have seen no reference on their format, all I
know is that the test image I got used a format like this for your
example of "CATDog":
'C' 0x00 'A' 0x00 'T' 0x00 'D' 0x00 'o' 0x00 'g'
So PEL simply loads data from these tags by skipping over NULL bytes
and saves it again with a NULL byte between each byte of text. You can
find the code in PelEntryByte.php line 238 and PelIfd.php line 404.
> if I do a
>
> $tags = $ifd0->getEntries();
>
> foreach($tags as $nr=>$tag) echo "$nr ".$tag->getValue()."<br>";
>
> directly after the above code - the XP_TITLE tag is found.
This is because the data is kept in the PelEntryWindowsString object
just created. The data is kept in decoded form (as "CATDog").
> if I have PEL save the data, load it again, and then run the lines
> above again, the XP_TITLE tag isnt found anymore (but there).
That sounds like a bug.
> this only happens for tags I create with
>
> new PelEntryByte(PelTag::PEL_TAG, "string");
>
> my
>
> $desc = new PelEntryAscii(PelTag::IMAGE_DESCRIPTION, $description);
>
> is saved and found after that just like it should.
That is also tested much more, both by users and by the unit tests.
> anybody got an idea of how to fix this - or is it me being stupid?
I don't know a fix for this, and unfortunately I don't have time to
debug this now.
For debugging I suggest you use a hex editor (I've used ghex) and lots
of print statements. Try inserting a tag using WinXP, and dump it with
debug output (dump-image.php -d or Pel::setDebug(true)). That gives
you some information about the offsets found by PEL, maybe you can
learn something from this.
--
Martin Geisler --- <[EMAIL PROTECTED]> --- http://mgeisler.net
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