Filed: http://trac.yorba.org/ticket/2555
On 13 September 2010 18:17, Mattias Põldaru <mahf...@gmail.com> wrote: > Ühel kenal päeval, E, 2010-09-13 kell 17:57, kirjutas Tim: >> On 10 September 2010 01:13, Mattias Põldaru <mahf...@gmail.com> wrote: >> > JPG files can contain EXIF data, which specifies it's orientation. This >> > is good, because JPEG is lossy format and every time you reencode it, >> > you loose some information. Doing real rotate in file is not possible >> > without reencoding. >> > The problem is, not all software can handle EXIF rotate right. But GIMP >> > can, it asks on opening, whether to rotate the image or not (since it >> > has to reencode it anyway). >> >> Apparently this isn't so. jpegtran (in package libjpeg-progs in >> Ubuntu/Debian) has a lossless rotator (plus a few other functions). >> >> From the man page. >> >> jpegtran works by rearranging the compressed data (DCT >> coefficients), >> without ever fully decoding the image. Therefore, its >> transformations >> are lossless: there is no image degradation at all, which would not >> be >> true if you used djpeg followed by cjpeg to accomplish the same >> conver‐ >> sion. But by the same token, jpegtran cannot perform lossy >> operations >> such as changing the image quality. >> >> More information should be at http://jpegclub.org/ >> I believe not every JPEG can be rotated in this fasion, but a good >> number can be. >> >> Personally, I prefer if the camera ether rotates it, or the final >> viewing software rotates it. But maybe an option at import time to >> rotate images would be good? My old camera import script would run all >> my photos through exiftran which does the same lossless rotations as >> jpegtran but also updates the exif information to reflect the rotation >> (and got the rotation direction from the exif). >> http://linux.bytesex.org/fbida/ for exiftran >> >> Tim >> > Thank you for clarification. I really didn't know about jpegtran. Would > you file a feature request for this? Such an option on importing from > camera sounds reasonable (this would also need removing the EXIF > rotation information). I hope developers agree :) > > Mattias > > -- Timothy White - Somewhere in Australia _______________________________________________ Shotwell mailing list Shotwell@lists.yorba.org http://lists.yorba.org/cgi-bin/mailman/listinfo/shotwell
