RE: [PEAR-DEV] JPEG Metadata Package

It seems to me that a JPEG file is composed of an aggregate of Image_IPTC and Image_EXIF. It seems wrong to inherit Image_TIFF from Image_JPEG. Note that Image_IPTC does not require the PHP user to have to recompile PHP for exif support (--enable-exif) - it works with a default out-of-the-box installation. It might be better to have an Image_Metadata class from which Image_IPTC and Image_EXIF inherit, however, since both must use imagegetsize() and both probably have a commit() or save() method of some sort. This would, of course, change our class names to the names of: Image_Metadata_IPTC Image_Metadata_EXIF It would seem to me also, that an Image_JPEG class when then have the ability to include those classes and create a composition of both. The same would be true of a TIFF and perhaps a PSD file. If you have questions, comments, or suggestions about the aforementioned message, you can respond by replying to this message or contacting us at (309)-743-0800. Thank you. Regards, Patrick O'Lone Internet Software Engineer TownNews.com (309)-743-0809 polone@townnews.com > -----Original Message----- > From: Sebastian Delmont [mailto:sdelmont@zonageek.com] > Sent: Monday, May 05, 2003 2:35 PM > To: pear-dev@lists.php.net > Subject: Re: [PEAR-DEV] JPEG Metadata Package > > > > > A problem with releasing all of them in a JPEG package is that TIFF > > files can also have IPTC headers. > > > > That's a very good point... > > TIFF and JPEG are the only Image formats that share a big chunk of > structure. Actually, add Photoshop's PSD to that list. No other > "popular" format uses IPTC (as far as I know). > > The "exif" part of JPEG is actually a partial TIFF file. And > "iptc" is > actually a partial PSD file. So my Image_JPEG already has 99% of the > code needed to parse TIFF and PSD files. > > Creating a global Image_Metadata module would be too ambitious, and I > don't want to spend time creating a single universal metadata > abstraction that can cover PNG, GIF, BMP, etc... After all, there's a > reason I'm using PHP instead of Java. And most of those formats don't > have any metadata at all besides the image dimensions and > perhaps some > comments. > > Creating a single Image_JPEGTIFFPSD module is actually rather simple. > But naming that module might be an issue... JPEGTIFFPSD > doesn't actually > sounds right, at least not to me... Image_JPEG, Image_TIFF > and Image_PSD > sound better, and Image_TIFF and Image_PSD could be very > simple classes > inheriting everything from Image_JPEG. I don't really know how PEAR > would handle something like this, but in the worst case it would mean > indicating a dependency between the packages. > > Another choice would be Image_IPTC + Image_EXIF, but that makes using > the package much harder, since you might need two different > objects to > manipulate a single file. Two separate parsings, two separate saves, > etc... And trying to hide those using a shared object or > something like > that would be a lot more complex. > > I haven't worked on Image_TIFF or Image_PSD yet for lack of time and > necessity, but again, they would be very simple to implement. > > Anyway... that's just my opinion ;-) > > Regards, > Sebastian > > > > > -- > PEAR Development Mailing List (http://pear.php.net/) > To unsubscribe, visit: http://www.php.net/unsub.php >