[Kde-imaging] [Bug 146381] Image rotation splits the image with a small strip appearing on the wrong side.

[Martin Rehn]

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http://bugs.kde.org/show_bug.cgi?id=146381         




------- Additional Comments From martinrehn hotpop com  2008-07-21 09:02 -------
I can reproduce this bug with Gwenview 1.4.2. I assume that Gwenview is using the same code for its rotation operation?

In my case, any image straight off a Sony DSC-V1 camera suffers from this problem. These pictures are 2592x1944 pixels. When I rotate to the right, in the rotated picture the eight rightmost pixels are taken from the left of the rotated picture. It looks very bad.

Command-line jpegtran shows the same behaviour. But: if jpegtran is given the additional flag "-perfect", it refuses to rotate the image with the message "jpegtran: transformation is not perfect". So it seems that, at least with the jpegtran algorithm, lossless rotation of these images is not possible?

This still looks like a bug in the jpegtran code, but at the very least it should be possible to incorporate the check done by the command line flag "-perfect" into the KDE copy of the code and do something sensible if it fails. I don't know what that would be, though.