1.91.6: Lossless JPG rotation not lossless?
Posted: Fri Nov 30, 2007 7:51 am
It seems that lossless JPG rotation is not lossless for JPG pictures which contain orientation info in EXIF that picture is rotated (right-top (6) in my case).
I've made a test like the one described here:
http://www.impulseadventure.com/photo/l ... -test.html
The issue can be related to the fact that for the picture, to rotate it by 360 degrees left, I have to press Ctrl-Shift-L 3 times (not 4). When I press Ctrl-Shift-L for the first time, it rotates picture by 180 deg.
Similar for rotation 360 right - 5 times (first time doesn't rotate picture at all).
I've made the same test with other JPG picture taken with the same camera (Canon A570IS), but without orientation info in EXIF (to be precise: top-left (1) ) and it works fine.
I'm not sure how EXIF info can affect lossless rotation but apparently it does
Picture size is 2304x3072 (multiplicity of 16)
XnView version: 1.91.6
OS: Windows XP SP2
-mirszy
I've made a test like the one described here:
http://www.impulseadventure.com/photo/l ... -test.html
The issue can be related to the fact that for the picture, to rotate it by 360 degrees left, I have to press Ctrl-Shift-L 3 times (not 4). When I press Ctrl-Shift-L for the first time, it rotates picture by 180 deg.
Similar for rotation 360 right - 5 times (first time doesn't rotate picture at all).
I've made the same test with other JPG picture taken with the same camera (Canon A570IS), but without orientation info in EXIF (to be precise: top-left (1) ) and it works fine.
I'm not sure how EXIF info can affect lossless rotation but apparently it does
Picture size is 2304x3072 (multiplicity of 16)
XnView version: 1.91.6
OS: Windows XP SP2
-mirszy
