snap version does not use my subpixel rendering settings

[soredake]

Originally reported here https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1916342

Steps to reproduce

1. Start telegram from snap
2. Fonts using grayscale rendering instead of my settings (rgb)

Expected behaviour

Snap should import my font settings from ~/.config/fontconfig/fonts.conf and use rgb subpixel rendering

Actual behaviour

Telegram from snap uses default grayscale rendering, due to not importing user font settings.

Configuration

Operating system: Kubuntu 20.10

Version of Telegram Desktop: 2.5.9

Installation source (Linux Only) - the official website / GitHub releases / flatpak / snap / distribution package: Snap

Used theme:

Logs:

Insert log.txt here (if necessary)

[ilya-fedin]

Snap should import my font settings from ~/.config/fontconfig/fonts.conf and use rgb subpixel rendering

tdesktop snap doesn't have anything special about font settings... Only standard snap scripts.

[soredake]

Snap should import my font settings from ~/.config/fontconfig/fonts.conf and use rgb subpixel rendering

tdesktop snap doesn't have anything special about font settings... Only standard snap scripts.

https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1916342/comments/3 https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1916342/comments/5

https://git.launchpad.net/~chromium-team/chromium-browser/+git/snap-from-source/tree/snapcraft.yaml#n15

[ilya-fedin]

I don't want to implement font settings reading manually...

[soredake]

@john-preston

[ilya-fedin]

I would say this is ridiculous, making font settings reading to be manually implemented by snap developers. I don't imagine how each app will parse fontconfig files manually...

[soredake]

I would say this is ridiculous, making font settings reading to be manually implemented by snap developers. I don't imagine how each app will parse fontconfig files manually...

Chromium in snap does this automatically, and i don't see any manual font settings loading in snapcraft file.

[ilya-fedin]

Chromium in snap does this automatically

How does it do?

[ilya-fedin]

I'm afraid it is not related to fontconfig... gtk reads font settings from xsettings/gsettings rather than from fontconfig files, so chromium and other gtk applications will just work once you set font rendering settings in your DE (if it sets the settings for gtk).

[anonymouse64]

Can the telegram desktop be adapted to use one of the snapcraft extensions which provide this functionality automatically? see https://snapcraft.io/docs/snapcraft-extensions

[ilya-fedin]

Can the telegram desktop be adapted to use one of the snapcraft extensions which provide this functionality automatically?

No, kde-neon extension is garbage. Here I stated why.

[ilya-fedin]

@soredake will font style be right if you run Telegram with XDG_CURRENT_DESKTOP=GNOME?

[soredake]

@soredake will font style be right if you run Telegram with XDG_CURRENT_DESKTOP=GNOME?

Yes, with "GNOME" rgb is applied to telegram fonts, but hinting (i set it to medium, default is slight) is not.

Save picture and zoom to maximum to see difference.

snap with XDG_CURRENT_DESKTOP=GNOME

flatpak with --filesystem=xdg-config/fontconfig:ro

[ilya-fedin]

but hinting (i set it to medium, default is slight) is not.

xrdb -query | grep Xft.hintstyle

[ilya-fedin]

Yes, with "GNOME" rgb is applied to telegram fonts, but hinting (i set it to medium, default is slight) is not.

btw, does chromium have the same problem?

[soredake]

but hinting (i set it to medium, default is slight) is not.

xrdb -query | grep Xft.hintstyle

Do i need to run it in snap or host system?

[ilya-fedin]

Do i need to run it in snap or host system?

on host

[soredake]

Yes, with "GNOME" rgb is applied to telegram fonts, but hinting (i set it to medium, default is slight) is not.

btw, does chromium have the same problem?

Yes, same problem with snap version.

snap:

ppa:

[soredake]

Do i need to run it in snap or host system?

on host

[ilya-fedin]

Yes, same problem with snap version.

So snap doesn't really support fontconfig even with extensions. Chromium works with rgba just because gtk reads settings from Xft (Qt does the same if XDG_CURRENT_DESKTOP is set to one of GNOME, UNITY, XFCE) rather than from fontconfig.

[ilya-fedin]

@Aokromes looks like you can close the issue, it's an issue with snap itself

[soredake]

@anonymouse64 can you reopen my launchpad issue? Because using extensions is clearly not an option.

[soredake]

Yes, same problem with snap version.

So snap doesn't really support fontconfig even with extensions. Chromium works with rgba just because gtk reads settings from Xft (Qt does the same if XDG_CURRENT_DESKTOP is set to one of GNOME, UNITY, XFCE) rather than from fontconfig.

Sad that it does not read Xft.hintstyle.

[ilya-fedin]

Sad that it does not read Xft.hintstyle.

It reads, as I can see in Qt code. The difference might be due to another reason (e.g. the difference in freetype versions).

[ilya-fedin]

Or it could be due to some more fontconfig-specific settings like lcd filter

[soredake]

Yes, same problem with snap version.

So snap doesn't really support fontconfig even with extensions. Chromium works with rgba just because gtk reads settings from Xft (Qt does the same if XDG_CURRENT_DESKTOP is set to one of GNOME, UNITY, XFCE) rather than from fontconfig.

So, i've done sudo cp ~/.config/fontconfig/fonts.conf /etc/fonts/local.conf, reinstalled chromium in snap, and now font rendering is same, fonts hook is indeed working, it just does not read ~/.config/fontconfig/fonts.conf

https://bugs.launchpad.net/ubuntu/+source/snapd/+bug/1916867

[github-actions]

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