XnView Software

Hello, i'm novice to XNVIEW and i'm trying to use it for my needs.

I found that lossless rotation is not lossless... i verified this problem using the procedure described at

http://www.impulseadventure.com/photo/l ... -test.html

I've already used this procedure for testing other tools (for example AcdSee passed the test, JPEG LossLess Rotator didn't etc.).

Bye.

Luca

That linked reference is misleading because it prompts visitor to 'resave and compare to original'. Saving jpeg according to quality settings (ex. 75%) should not be confused with a lossless jpeg operation which directly modifies file. It is better to use lossless rotate tool without resaving image.

Sorry, but i didn't save anything (directly).

I wanted to use XnView as a browser, for rotating images that need it. So this is what i did:

- i selected my folder in the left tree so all my pictures where displayed on the top right as thumbnails
- i clicked a picture and it was displayed on bottom right preview area
- i selected Outils/Transformations JPEG sans perte/Rotations 90° à droite (4 times in this case for obtaining a picture with same rotation as the original)
- than i made the comparison test (i previously made a copy of the original picture) describred in the link mentioned in previous e-mail with faulty result

If you make the exact same sequence with AcdSee you will obtain a perfectly equal picture as the original.

You can say: USE ACDSEE (i have a regular copy of it)!

But i think that your tool is better and this is the reason i'm wasting my time writing this e-mail.

Thanks.

Luca

I can reproduce the file difference by rotating the file 4 times, but the result still isn't lossy. After rotaing the file, I saved the original image and the rotated copy as windows bitmap (any lossless format should be fine) and then compared the bitmaps instead of the jpgs. This way I exluded all the differences that that doesn't effect the actual image data (e.g. metadata).