JPEG Lossless: Auto-rotate (EXIF) does not adhere to "Perfect" transformation

[Bhikkhu Pesala]

Thanks for the update. I modified the thread’s status. Did you read the Bug Reports sticky thread?

[TFGYG786]

All right, might be more clear to add a disclaimer/explanation as to what this forum can be used for then.

Anyway, Irfan has just fixed this issue and sent me a working new version of the plugin. So it'll probably be available for everyone in the next update.

[Bhikkhu Pesala]

Then why isn't this forum closed?

To save Irfan Skiljan dealing with duplicate reports, or badly formulated reports.
Often, other users can say if a bug report has been submitted already, or that the reported issue is not a bug at all.

[TFGYG786]

Then why isn't this forum closed?

[Kuki Dent]

The developer of IrfanView does not read this forum. If you found a bug or have a feature request you need to write him an email.
See Help > About for his mail adress.

[TFGYG786]

IrfanView v4.72 x64
Jpg_transform.dll v4.71 (from v4.72 archive)

Test images: JPEG from phone camera, dimensions 2944 x 1656, or dimensions 4032 x 2268.

I just found out that the combination of enabling Auto-rotate (according to EXIF orientation, if available) + "Perfect" transformation only (don't cut OFF rows/columns in this case) does not show the expected behavior: instead of warning that a perfect rotation isn't possible ("Bad image dimensions"), it just acts like the Perfect transformation isn't selected and does a lossy rotation that cuts off a strip of 8 pixels.

In contrast, 90 and 180 degrees of the manual rotation options, plus vertical flip, do show this warning message.