Lossless Rotate Bug?, image size gets altered when using lossless rotate bug? Options

[fbakan]

Hi,

don't know if this is OS/2-specific, but here's my problem:

For example I have a .jpg file 454x480 pixels. When I now chose
rotate lossless 180 degree the size gets altered and now is 448x480.
This is not lossless, the picture loses some pixels!
There is even no option for 'undo', so the original image gets destroyed.

I think this is a rather severe bug or am I wrong?

(version 3.40, but at least 3.31 also has this bug)

Thanks for listening
Franz

[Peter]

Correct. The image width/height needs to be divisible by 8, the size of one MCU block (8x8).

Since the size of your image isn't divisible by 8, it has probably already been subject to a lossy transformation. Lossless transformation will generate garbage out of partial MCU blocks. Instead of presenting the garbled edges to the user, PMView does what most users probably prefer and cuts out the garbled blocks.

Usually this is not an issue, since camera originals typically have a size that is divisible by 8 and can be rotated losslessly without the need to throw away anything.

Peter