Pixelated images in Telegram under fractional scaling in KDE

Telegram shows pixelated images, emojis and stickers when fractional scaling is enabled in KDE Plasma. This issue has been reported in https://github.com/telegramdesktop/tdesktop/issues/23953, but it would require “almost full rewrite” to fix it, according to the developers. I am using X11, not sure about Wayland.

Image source: GitHub issue

Disabling scaling in the desktop file fixes the issue in the telegram client, but it causes the child processes to lose scaling capabilities.

A workaround is to use this AUR package https://aur.archlinux.org/packages/telegram-desktop-bin

Is there any other workaround (other than recompiling telegram as mentioned here)?

Also, the upstream devs are not interested in fixing this bug affecting Arch Linux (and Arch based operating systems). Can it help if I open a bug report against the Arch Linux package?

Wayland session?

See this https://pointieststick.com/2022/06/17/this-week-in-kde-non-blurry-xwayland-apps/

No, I am using X11

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Setting variable QT_SCALE_FACTOR=0.8 at Exec line in telegramdektop.desktop file (now it’s looks like Exec=QT_SCALE_FACTOR=0.8 telegram-desktop – %u) helped me. If that doesn’t help, you can try to choose other value for QT_SCALE_FACTOR variable.

That would probably affect the child processes. If you open a pdf document from telegram with Okular, that window will also probably not have fractional scaling.
See https://github.com/telegramdesktop/tdesktop/issues/23953#issuecomment-1049069084 and the following comment.

Can you please check and let us know?

Have you tried using font DPI scaling instead of fractional scaling in plasma?

I know it is not an intuitive solution but most UI elements scale with the font so it actually makes almost everything bigger.

I don’t know why, but I haven’t this issue. There is no affect on any child process (tested on Google Chrome, Okular, Dolphin).
I should notice my system settings: global scale = 125%; font DPI = 120; telegram scale = 150%.

Welcome to the EndeavourOS forum. I hope you enjoy your time here.


Sorry, found issue. There is a problem with open file dialog. It is clearly smaller than in other (normal) programms. But its better than this ugly pixelated images. And I don’t want to use AUR package because hardware video decoding does not work for me there.