Preview Alpha Channel in XnView Classic is broken

Bugs found in XnView Classic. Please report only one bug per topic!

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esenthel
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Joined: Mon Jun 08, 2015 7:00 am

Preview Alpha Channel in XnView Classic is broken

Post by esenthel »

Latest release broke previewing images with alpha channels.
Press M to see alpha channel (show mask menu) doesn't always work, sometimes you need to press Ctrl+H first (Use Alpha Channel)
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xnview
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Re: Preview Alpha Channel in XnView Classic is broken

Post by xnview »

could you send me a picture file where it doesn't work?
Pierre.
esenthel
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Re: Preview Alpha Channel in XnView Classic is broken

Post by esenthel »

In latest version 2.49.4

Please use any image that has alpha channel, BMP, PNG, TGA, any
Then set zoom to be less than 100%, for example 50%,
Then press M key to show alpha, it won't work

Zoom in at 100%, alpha starts to work

In options I have "High Quality Zoom \ Reduce = ON"
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xnview
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Re: Preview Alpha Channel in XnView Classic is broken

Post by xnview »

it works here
Pierre.
esenthel
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Re: Preview Alpha Channel in XnView Classic is broken

Post by esenthel »

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xnview
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Re: Preview Alpha Channel in XnView Classic is broken

Post by xnview »

esenthel wrote: Sun Nov 08, 2020 7:01 am It's broken 100%
https://youtu.be/H5jyZxcHdUI
I can't reproduce, could you send me the file used, and which settings do you have in options>View?
Pierre.
esenthel
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Re: Preview Alpha Channel in XnView Classic is broken

Post by esenthel »

The problem happens with any/all images that have alpha channel.
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xnview
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Re: Preview Alpha Channel in XnView Classic is broken

Post by xnview »

it's crazy, it works correctly here
Pierre.
esenthel
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Re: Preview Alpha Channel in XnView Classic is broken

Post by esenthel »

Could it be related to Windows?
I have the latest version: Win 10 Home, ver 2004, os build 19041.508

But I've tested an older version, 2.37 just now, and it doesn't suffer from the same problem.
So I think something got broken in your code.
It was working fine just couple releases ago.

Is there a way to download older versions of your software? (v 2.48, 2.47 or something)
I could tell you between each release where the problem occurred, and you could check your code base for changes in that time frame, to see which change broke this function.
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xnview
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Re: Preview Alpha Channel in XnView Classic is broken

Post by xnview »

esenthel wrote: Thu Dec 03, 2020 5:30 am Could it be related to Windows?
I have the latest version: Win 10 Home, ver 2004, os build 19041.508
no it's XnView
Is there a way to download older versions of your software? (v 2.48, 2.47 or something)
http://download.xnview.com/old_versions
Pierre.
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XnTriq
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Re: Preview Alpha Channel in XnView Classic is broken

Post by XnTriq »

I'm not able to reproduce this issue with XnView Classic v2.49.4 and 966_1578623403.png or any other 32-bit PNG. However, we had a similar report a couple of years ago.

Related: Recommended settings
esenthel
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Re: Preview Alpha Channel in XnView Classic is broken

Post by esenthel »

I've tested a bunch of versions:
2.39 works great, no issue
2.40 has different problem, black background and white pixels on the border
2.40.png
2.41+ has problems with alpha sometimes visible, sometimes RGB, depending on zoom < or > 100%
Something got broken between 2.39 and 2.40

Attaching the entire XnView.ini file with settings, maybe you can do tests with it.

My Windows DPI Settings in 125%
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XnTriq
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Re: Preview Alpha Channel in XnView Classic is broken

Post by XnTriq »

Hello esenthel

I ran XnView v2.49.4 with the INI you provided (Windows DPI = 120%) and opened flour-flower-png-transparent-png-images-pluspng-2.png in fullscreen, edit and preview. Although I watched your screen recording again and made sure to follow the steps outlined in one of your previous posts…
esenthel wrote: Fri Oct 23, 2020 4:34 amIn latest version 2.49.4

Please use any image that has alpha channel, BMP, PNG, TGA, any
Then set zoom to be less than 100%, for example 50%,
Then press M key to show alpha, it won't work

Zoom in at 100%, alpha starts to work

In options I have "High Quality Zoom \ Reduce = ON"
… everything works as expected :-?

Related: Transparent pixels dont get filtered correctly