XnView Software

Hi,

Steps to reproduce the bug:
1/ open Mp 096.5
2/ tools>General>Operations on files
verify that "lossless operations on JPEG" is checked
3/ open some jpeg picture (preferably in high dpi)
4/ do some cropping, for instance take some 4:3 picture and crop it in 16:9
5/ save the cropped version with some filename (add for instance suffix _mp_cropped)
6/ do the same cropping operation on some apps supporting lossless cropping (see https://linux.die.net/man/1/jpegtran), for instance FastStone Image Viewer.
You'll notice that XnViewMP does not do a lossless crop, but rather re-encodes the jpeg.

Thanks for fixing

if you re-save a picture file, you'll never have a lossless operation. Please use Lossless operations>Crop

Sorry, I didn't get a notification of your reply.

>if you re-save a picture file, you'll never have a lossless operation.
Maybe there is a misunderstanding, but with FSViewer or LossCrop I can crop and save in lossless mode, with XnViewMP I do see a noticable difference in file size when I perform same cropping, or in rotation
operation is performed on a portion of an image without incurring any additional recompression error.

I'm not doing a re-save, I'm saving the rotated or cropped image (no new quality setting or whatever)

>Please use Lossless operations>Crop
I do wish that the crop and rotation button on the toolbar are lossless operations unless not possible
(I think algorithm constrains to even pixel, so FSViewer lossless crop is to the nearest pixel allowing lossless cropping)


I have an image for which when I load the lossless crop is not avaible (rotations are, crop is in gray mode)

Thanks

mustbeit wrote: Tue Sep 22, 2020 8:54 am >if you re-save a picture file, you'll never have a lossless operation.
Maybe there is a misunderstanding, but with FSViewer or LossCrop I can crop and save in lossless mode, with XnViewMP I do see a noticable difference in file size when I perform same cropping, or in rotation

For me FSViewer re-save picture data, like XnView

I do wish that the crop and rotation button on the toolbar are lossless operations unless not possible

You can add lossless operations in toolbar