exif

I think, that jpegtran should update the exif data. So, applying twice detection&rotation is ok.

my patch http://www.ruska.it/comp/gentoo/portage/media-libs/jpeg/files/exif.patch is an extension of Exif Patch (Jan 07 2001). I added the orientation rewriting.

I tried to decode the number/orientation-value as 3 bits and decomposed them to (as elements of a group) express the transformations as simple automorphism in 0/1 tripples.

HOw i tested:

./.libs/jpegtran -copy all -rotate 180 -outfile /tmp/test.jpg /tmp/foto/07-01/test.jpg [FIXME: invalid characters]

http://www.hugsan.com/EXIFutils/Documentation/EXIFutils-FieldRef1.htm

so, i patched jpeg-6b-r6.ebuild

i received fotos with wrong orientation:

exif -t 0x0112 --ifd 0 --set-value 8 file