Perfect lossless JPEG transformation

[Marcus Sundman]

It would be nice to have an option to require lossless transformations to be perfect, and if one or more of the selected images contain "junk pixels" XnView would show an error message instead of performing the transformation.

[xnview]

It would be nice to have an option to require lossless transformations to be perfect, and if one or more of the selected images contain "junk pixels" XnView would show an error message instead of performing the transformation.

If you have a width/height not correct for lossless rotation, you want to not apply it, is it right?

[Xyzzy]

Yes, I think Marcus meant just that.

Also in http://newsgroup.xnview.com/viewtopic.php?t=1360 lawndart mentions some lossy rotation function. Is this the one in file view, Image->Rotate? Is lossy rotation function available anywhere else?

I would like to see options to disable ANY lossy operations for lossy formats, with possibility to set options like 'Ask when trying to perform lossy operation on a lossy format', 'Deny lossy operation on a lossy format', 'Quietly deny lossy operation on a lossy format' (that would be usable in batch operations).
X

[Marcus Sundman]

It would be nice to have an option to require lossless transformations to be perfect, and if one or more of the selected images contain "junk pixels" XnView would show an error message instead of performing the transformation.

If you have a width/height not correct for lossless rotation, you want to not apply it, is it right?

Yes, kinda. If I select "Trim image (Remove unused pixels)" then those "junk pixels" would be removed and thus the width or height would be incorrect, but if I don't select it then the width and height would still be correct even if the image would have some incorrectly transformed pixels along the bottom or the right hand side.

Uh.. that got a bit complicated. I'll rephrase it. I want to tell XnView that it should transform an image only if all pixels in the image can be transformed correctly.

I would like to see options to disable ANY lossy operations for lossy formats, with possibility to set options like 'Ask when trying to perform lossy operation on a lossy format', 'Deny lossy operation on a lossy format', 'Quietly deny lossy operation on a lossy format' (that would be usable in batch operations).

That's a great idea!
However, I would like to have these options instead:

• Always allow lossy operation on a lossy format.
• Never allow lossy operation on a lossy format. (Show an error message when the user tries to do that.)
• Ask before applying lossy operation on a lossy format.

Then I would move the "Quietly deny [...]" to the batch utility and change it to "Don't display error messages."

[xnview]

If you have a width/height not correct for lossless rotation, you want to not apply it, is it right?

Yes, kinda. If I select "Trim image (Remove unused pixels)" then those "junk pixels" would be removed and thus the width or height would be incorrect, but if I don't select it then the width and height would still be correct even if the image would have some incorrectly transformed pixels along the bottom or the right hand side.

Uh.. that got a bit complicated. I'll rephrase it. I want to tell XnView that it should transform an image only if all pixels in the image can be transformed correctly.

Ok, i understand, but why such option is needed?

I would like to see options to disable ANY lossy operations for lossy formats, with possibility to set options like 'Ask when trying to perform lossy operation on a lossy format', 'Deny lossy operation on a lossy format', 'Quietly deny lossy operation on a lossy format' (that would be usable in batch operations).

That's a great idea!
However, I would like to have these options instead:

• Always allow lossy operation on a lossy format.
• Never allow lossy operation on a lossy format. (Show an error message when the user tries to do that.)
• Ask before applying lossy operation on a lossy format.

Then I would move the "Quietly deny [...]" to the batch utility and change it to "Don't display error messages."

In this case, almost all operations can not be done....

[Marcus Sundman]

If you have a width/height not correct for lossless rotation, you want to not apply it, is it right?

Yes, kinda. If I select "Trim image (Remove unused pixels)" then those "junk pixels" would be removed and thus the width or height would be incorrect, but if I don't select it then the width and height would still be correct even if the image would have some incorrectly transformed pixels along the bottom or the right hand side.

Uh.. that got a bit complicated. I'll rephrase it. I want to tell XnView that it should transform an image only if all pixels in the image can be transformed correctly.

Ok, i understand, but why such option is needed?

Because I don't want to do anything irreversible (and I don't want any pixel mess at one of the sides). E.g. if my printer company uses a certain resolution then I certainly don't want my picture to become any other resolution just because I performed a "lossless" transformation on it. In that case I'd rather have it in the wrong orientation (at least until I've ordered my prints).

I would like to see options to disable ANY lossy operations for lossy formats, with possibility to set options like 'Ask when trying to perform lossy operation on a lossy format', 'Deny lossy operation on a lossy format', 'Quietly deny lossy operation on a lossy format' (that would be usable in batch operations).

That's a great idea!
However, I would like to have these options instead:

• Always allow lossy operation on a lossy format.
• Never allow lossy operation on a lossy format. (Show an error message when the user tries to do that.)
• Ask before applying lossy operation on a lossy format.

Then I would move the "Quietly deny [...]" to the batch utility and change it to "Don't display error messages."

In this case, almost all operations can not be done....

Excuse me? E.g. if I choose "Never allow lossy operation on a lossy format. (Show an error message when the user tries to do that.)" then all operations should still be doable on all pictures with a width and height that are multiples of 16 (perhaps it's even enought that they be multiples of 8). Have I misunderstood something?