Lossless transformation: 180° rotation instead of 90°

[geobrick]

version 1.92.2
Clicking on the lossless transformation down arrow or in the dialog box for a 90 degree rotation (left or right) does a 180 degree rotation. When doing it again in the oppisite (to correct the over rotation) works fine.

[helmut]

Hmm, no problem here. Perhaps a problem related with 'XnView's automatic image rotation?'? Do you have checkbox 'Reset EXIF orientation value' checked or unchecked?

[geobrick]

Helmut,
Sorry for the delayed response. I was away.

I do have the 'Reset EXIF orientation value' checked. Also, I do not have "Rotate images based on EXIF orientation" selected in the general section of options.

Here is a step by step example (using 1.96.2):
- The original image needs to be rotated 90 degrees ccw (left).
- The orignal EXIF orientation is Left-Bottom (8).
- In the Browser Window, I select the thumbnail of the image.
- I then click the JPEG Lossless Transformation button on the tool bar.
- 'Keep original date/time attributes' and 'Reset EXIF orientation value' are both checked.
- I click "-90 degrees" and click go.
- The thumbnail and the preview show the image now rotated 180 degrees from the original not the -90 I wanted. (Windows explorer shows the same).
- The EXIF orientation value is now Top-Left (1) but the image is not right.
- (Same happens when selecting the "rotate 90 degrees left" from the down-arrow on the tool bar)

- I fix it by repeating the process above except I click "+90 degrees" and click go. This correctly rotates the image.

Other notes:
If I select the rotate by EXIF value, it works correctly. This problem only seems to happen when the original image needs to be rotated -90 degrees (ccw) and the the orignal EXIF orientation is Left-Bottom (8). In all other cases, the "rotate 90 degrees left" seems to work.

(Using WinXP SP3).

[xnview]

Could you send me a jpeg sample?

[Hacker]

Hello all,
I can confirm the report. It works fine when the "Reset EXIF orientation value" is unchecked. However, when checked, the image gets rotated weirdly. Try for yourself with the image at http://a.img-dpreview.com/gallery/leica ... 070414.jpg .

Reset EXIF orientation value checked:
- Rotate -90 degrees: does not seem to do anything
- Rotate +90 degrees: rotates +180 degrees
- Rotate +180 degrees: rotates +270 degrees
- Rotate EXIF: seems to work fine

Reset EXIF orientation value unchecked:
- Rotate -90 degrees: seems to work fine
- Rotate +90 degrees: seems to work fine
- Rotate +180 degrees: seems to work fine
- Rotate EXIF: seems to work fine

I am not sure if this is how it is supposed to work. It seems XnView is taking the EXIF orientation flag as the information how the image is currently rotated instead of the image itself. If the image is landscape but the EXIF orientation flag says it is portrait, XnView thinks it indeed is portrait.

TIA
Roman

[Hacker]

Not fixed in 1.96.5.

Roman

[xnview]

I can confirm the report. It works fine when the "Reset EXIF orientation value" is unchecked. However, when checked, the image gets rotated weirdly. Try for yourself with the image at http://a.img-dpreview.com/gallery/leica ... 070414.jpg .

Be careful, if this option is enabled, ONLY the EXIF orientation field will be changed. Picture will not be rotated!!!

[Hacker]

Ah, I see. So I guess it works as expected?

Roman

[xnview]

Ah, I see. So I guess it works as expected?

Yes, for me

[Hacker]

I can confirm the report. It works fine when the "Reset EXIF orientation value" is unchecked. However, when checked, the image gets rotated weirdly. Try for yourself with the image at http://a.img-dpreview.com/gallery/leica ... 070414.jpg .

Be careful, if this option is enabled, ONLY the EXIF orientation field will be changed. Picture will not be rotated!!!

So perhaps it should say something like "Rotate EXIF orientation flag ONLY" or so, instead?

Roman

[flins]

Hi Pierre,
I've experienced the same problem. And, with hotkey Ctrl+Shift+R to rotate "Hacker" picture 90 degrees right, it rotate 180 degrees instead, with or without "Rotate EXIF" flag.
When first rotation is made, then others are fine.
Very good program anyway.

[marsh]

I've experienced the same problem. And, with hotkey Ctrl+Shift+R to rotate "Hacker" picture 90 degrees right, it rotate 180 degrees instead, with or without "Rotate EXIF" flag.
When first rotation is made, then others are fine.

Confirmed when following option is set:
Options... General>[ ]Rotate Images according orientation tag
It is rotating according to how image would appear with this option on, regardless of its state.

[xnview]

I've experienced the same problem. And, with hotkey Ctrl+Shift+R to rotate "Hacker" picture 90 degrees right, it rotate 180 degrees instead, with or without "Rotate EXIF" flag.
When first rotation is made, then others are fine.

Confirmed when following option is set:
Options... General>[ ]Rotate Images according orientation tag
It is rotating according to how image would appear with this option on, regardless of its state.

How to reproduce?

[marsh]

Steps:
1. Use any jpeg with right-top EXIF orientation (or change flag in exif preview).
2. Turn off option to rotate according to orientation flag (then thumbnail's rotate icons aren't visible anymore).
3. Press browser rotate right button or <ctrl + shift + r>
4. The image content shifts 180 degrees, and orientation flag is reset to top-left (on first pass).

[Hacker]

Seems to work fine in 1.97.7.

Thanks
Roman