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xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Wed Jul 12, 2023 2:22 pm
by xmozg
xnviewMP 1.5 64 bit win10 latest updates.
The appearance of image artifacts when reducing the image in view mode when using high-quality algorithms (except for billinear and none).
Problem reproduction:
1. set any high-quality algorithms in the options (from bicubic to lanczos4)
2. look at the images when they are reduced by a certain percentage. For example for 1080p (scale will be different for different resolutions
) image starting from 57% or less for lanczos4, 42% for lanczos3 and spline 36, 28% for spline 16 and bicubic.
Problem encountered: The image is darkened, showing horizontal shading stripes across the entire image, and a gray stripe at the bottom of the image.
Expected result: the image is displayed without all these stripes and retains visual content regardless of the scale.
Original 1080p image downloaded from here:
https://www.pixelstalk.net/wp-content/u ... wnload.jpg
Normal:
Artifacts with lanczos4 at 54%:
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Tue Aug 22, 2023 6:47 am
by xnview
i'm not able to reproduce. Do you use windows font scaling? could you post a screenshot of Settings>View?
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Tue Aug 22, 2023 11:01 am
by xmozg
I am not using any windows scaling.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Tue Aug 22, 2023 11:45 am
by xnview
i can't reproduce. You have this grey line each time, for each image?
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Tue Aug 22, 2023 12:01 pm
by xmozg
Line appearance depends only on the zoom algorithm and the zoom level itself. Clearer looking algorithm (toward lanczos 4) - earlier line appears when zooming out. A less sharp looking algorithm (spline 16 and bicubic) means that the image can be scaled down further until a line appears. Therefore, with the lanczos 4 algorithm, I see a line in most of the pictures.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Tue Aug 22, 2023 1:57 pm
by xmozg
I tried using the portable version with the default settings, changing only the "high zoom quality zoom out" setting. The problem hasn't changed. It's not about the settings.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Wed Aug 23, 2023 7:23 am
by xnview
xmozg wrote: Tue Aug 22, 2023 1:57 pm
I tried using the portable version with the default settings, changing only the "high zoom quality zoom out" setting. The problem hasn't changed. It's not about the settings.
Could you try to disable Settings>General>Icc? I've tried on another computer, but no problem, with same image & zoom level/algorithm
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Wed Aug 23, 2023 12:28 pm
by xmozg
I've tried turning this setting off, it doesn't help. Maybe indeed windows is stealthily interfering with the xnview? I have any processing and text scaling disabled in windows.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Wed Aug 23, 2023 12:35 pm
by xnview
xmozg wrote: Wed Aug 23, 2023 12:28 pm
I've tried turning this setting off, it doesn't help. Maybe indeed windows is stealthily interfering with the xnview? I have any processing and text scaling disabled in windows.
and no problem with 1.4.5?
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Wed Aug 23, 2023 1:51 pm
by xmozg
The bug occurs only on high quality zoom algorithms (bicubic or better), in version xnviewmp 1.4.5 it is impossible to enable high quality zoom out algorithms (bug 2790, fixed in 1.5.0), so there is no bug in it.
In version 0.98.2 it was possible to enable high quality zoom out algorithms (bicubic or better) and they worked without this bug with a gray line and without darkening of the picture. I don't know if this information is important.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Mon Aug 28, 2023 3:07 pm
by xnview
i send you a PM
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Mon Aug 28, 2023 5:34 pm
by Klaus1189
Same as
viewtopic.php?f=82&t=45754
I am not alone, but Dev takes care of it

Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Wed Aug 30, 2023 1:35 pm
by xnview

Thanks to your detailed description I can reproduce
the problem.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Tue Sep 05, 2023 1:33 pm
by xnview
This problem is supposed to be fixed in
XnView MP 1.5.4. Please check and confirm the bug fix here.
Re: xnviewmp 1.5.3 bug: artifacts when viewing with hq algorithms
Posted: Sat Sep 09, 2023 3:42 am
by xmozg
Bug is fixed
