1.8.0 - viewer - antialiasing - issue with dpi scaling

[user0]

XnViewMP 1.8.0
Windows11 (23H2), display resolution 3840x2160, dpi scale 150%

Viewer - zoom - anti-aliasing
few issues

To reproduce:
0. prerequisites
- clean portable version
- set win DPI scale >100%, eg 150%

1. have test image in folder

test_img.png (563 Bytes) Viewed 3892 times

2. (optional) assign shortcut to 'Anti-aliasing' for easier reach, eg B


Issue A
3. open image at 100% in Viewer
4. press B (and hold)
image will shift a bit, it looks like a filter is applied
occurs when any option other than None is selected for the Zoom Out (Settings>View)


Issue B
4. close app
5. open image via double click in win file explorer
6. make selection
7. press B and hover cursor over image
'Show color information' will be enabled
rotation controls will be available (at the selection corners)
8. click on View menu
sometimes 'Info' will appear
repeat 4-8 steps ~10 times to reveal all issues


Issue A1
1. have test images in folder

test_img_A1.zip

(1.09 KiB) Downloaded 2 times

2. check both images in Viewer at 100% with win dpi scale 150%
4bit and 1bit - have different filters applied

A1_1bit_vs_4bit.png (2.23 KiB) Viewed 56 times

Related

• issues
  1.8.2 - view - png - tRNS transparency - viewing issues
  - todo -
  1.8.8 - viewer - png - alpha transparency - clipboard issues
  1.8.0 - viewer - antialiasing - issue with dpi scaling (current post)
  1.7.1 - viewer - antialiasing - border at the edge of transparent png
  - fixed -
  1.5.0 - viewer - antialiasing - None still affects image (1.7.0)
  1.4.3 - viewer - antialiasing + HiDPI - extra space on zoom (1.5.0)
  1.4.0 - viewer - antialiasing + Change color depth issue (1.5.0)
  1.4.4 - viewer - antialiasing - state out of sync (1.4.5)

[xnview]

Issue A
3. open image at 100% in Viewer
4. press B (and hold)
image will shift a bit, it looks like a filter is applied
occurs when any option other than None is selected for the Zoom Out (Settings>View)

yes, if you use win DPI > 150%, image at 100% will be scaled. Only when you zoom at 67%, it's 1:1

[user0]

182
post updated with A1 issue

[xnview]

[user0]

Issue A
3. open image at 100% in Viewer
4. press B (and hold)
image will shift a bit, it looks like a filter is applied
occurs when any option other than None is selected for the Zoom Out (Settings>View)

yes, if you use win DPI > 150%, image at 100% will be scaled. Only when you zoom at 67%, it's 1:1

but why does Zoom-out filter affect image at 100% zoom?

in my understanding Zoom-out filter should only apply if you:
- set it <> Noone
- enable "High zoom quality" in Viewer (always enabled in Browser?)
- set image zoom <100%


it also looks like issue B is linked with the following issue that still exists:
1.5.0 - viewer - High zoom quality - None still affects image

[xnview]

If you use DPI scaling of 200%, and image zoom at 100%, you have not 1 pixel (image) on 1 pixel (display)

[user0]

copy of PM, so that everything is in one place

If you use DPI scaling of 200%, and image zoom at 100%, you have not 1 pixel (image) on 1 pixel (display)

right,
but I have issue with ranges at which you apply custom 'High zoom quality' filters which depends on win DPI scale.
In my understanding zoom-out/in threshold at which you apply filter should always be =100%.

lets compare behavior with other apps at winDPIscale 150%:

• ImageGlass and FastStone
  apply
  - zoom-out filters at 0-99% image zoom range -- as expected
  - zoom-in filters at 101-∞ image zoom range -- as expected

• XnViewMP
  apply
  - zoom-out filters at 0-149% image zoom range -- ???
  - zoom-in filters at 151-∞ image zoom range -- ???

Example

• ImageGlass
  Nearest Neighbour as 'None' option, which is a bit more explicit
  

• FastStone
  no zoom-in/out filter separation
  

ref
https://doc.qt.io/qt-5/highdpi.html
https://doc.qt.io/qt-6/highdpi.html
https://learn.microsoft.com/en-us/windo ... lity-scale