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.
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?
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.
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%.
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.