1.9.9 Transparent PNGs, WEBP and ICO not shown correctly

[pjaneto]

XnView: MP 1.9.9 64bit
OS : Windows 10 64bit

I updated XnViewMP from https://www.xnview.com/en/xnview-mp/#downloads
I always (and only) get updates from the original site.

Effect:
Transparent PNGs, WEBP and ICO not shown correctly in several cases.
I have added several images to show these cases.

There are 3 images for each case:
1) A screenshot of the way FastStone Viewer shows the image
2) A screenshot of the way XnView shows the image
3) The original image

They are named with the prefixes 1--, 2--, 3-- and 4--

In addition there is an image which shows correctly at 100% zoom but which displays INcorrectly when zoomed to 142%.
It is named without the prefixes:
Its name is Graph*.*

To reproduce:
Just view each image (on Windows double-click)

Actual behaviour (bug): Shows images incorrectly
Expected behaviour : To show images correctly

PS Edit: I was not able to post original WEBP file neither the ICO file, I will post the resulting screenshots in another message.

Best Regards,

pjaneto

[user0]

I was not able to post original WEBP file neither the ICO file, I will post the resulting screenshots in another message.

Archive originals and attach .zip file, no need to double post.

Transparent PNGs, WEBP and ICO not shown correctly in several cases.

enable transparency in View menu:
- Use transparent index
- Use alpha channel

In addition there is an image which shows correctly at 100% zoom but which displays INcorrectly when zoomed to 142%.

I can reproduce
1. set zoom-in/out to any except None and Bilinear
2. disable transparency index
3. open image and zoom-in/out
transparent index will became transparent

looks like regression appeared in 187
1.8.2 - view - png - tRNS transparency - viewing issues (test_img 2)

related
1.8.0 - viewer - antialiasing - issue with dpi scaling

[pjaneto]

Thank you for responding to my mail.
I set the View Menu to "Use alpha channel" and everything is fine, except with the ICO image.
Also I have a suggestion regarding the "Use alpha channel" option.

Concerning the ICO image:
When viewing the largest image in the ICO it looks fine.
But when using the "View→Navigate to→Next page" transparent pixels look black.

Concerning the "Use alpha channel" option:
This option is greyed out, when an image without transparent pixels is being viewed.
But this a global setting, it should be available always.
Or moved to the "Tools→Settings..." Menu.

BTW, I'm using XnView 1.9.10

Best regards,

pjaneto