Tdesktop: Kubuntu large icon task switcher

[bibendi]

Steps to reproduce

1. Go to System Settings - Window Managment - Task Switcher
2. Choose Large Icons
3. Change window by pressing Alt+Tab

Expected behaviour

Telegram icon is not blurred

Actual behaviour

Telegram icon is blurred

Configuration

Operating system: Kubuntu 20.04

Version of Telegram Desktop: 2.1.5

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

[ilya-fedin]

Looks like your icon theme has icons for all apps on the screenshot except Telegram

[bibendi]

I think this link would be very helpful https://bugs.kde.org/show_bug.cgi?id=351055

It can be fixed by the application itself.

[ilya-fedin]

It can be fixed by the application itself.

Please, TL;DR, what is needed?

[bibendi]

An app should provide correct/good icon to kwin.

Please, read comments 34-35
https://bugs.kde.org/show_bug.cgi?id=351055#c34

[ilya-fedin]

An app should provide correct/good icon to kwin.

tdesktop provides 256px icon. Is this good/correct?

[bibendi]

Unfortunately, I don't know :(

[bibendi]

I've found more information about the bug.

https://www.reddit.com/r/kde/comments/9kz6gv/please_make_kwin_automatically_recognise_correct/

TL;DR:

• An application should conform to the XDG icon theme standard.

https://specifications.freedesktop.org/icon-theme-spec/icon-theme-spec-latest.html

• A user can fix it for himself:
  1) Right click on title bar > more actions > special application settings > Appearances and fixes
  2) Enable Desktop file name + Select "Force" and specify the desktop file name

[ilya-fedin]

An application should conform to the XDG icon theme standard.

tdesktop installs icon to ~/.local/share/icons

[bibendi]

Okay, it seems, I've found the right answer.
The window should set _NET_WM_ICON property.
https://specifications.freedesktop.org/wm-spec/1.3/ar01s05.html

_NET_WM_ICON CARDINAL[][2+n]/32

This is an array of possible icons for the client. This specification does not stipulate what size these icons should be, but individual desktop environments or toolkits may do so. The Window Manager MAY scale any of these icons to an appropriate size.

This is an array of 32bit packed CARDINAL ARGB with high byte being A, low byte being B. The first two cardinals are width, height. Data is in rows, left to right and top to bottom.

You can inspect the properties of other application windows by using the xprop CLI.

[bibendi]

Also, I have a problem with the tray icon.

But it's a cool story of another investigation :)
Maybe you know where that icon is located to save my time?

[ilya-fedin]

The window should set _NET_WM_ICON property.

It is set, otherwise there wouldn't be any icon

[ilya-fedin]

Also, I have a problem with the tray icon.

7399

[bibendi]

It is set, otherwise there wouldn't be any icon

Yes, but there is only one 48x48 icon. Firefox has six icons.

[ilya-fedin]

Yes, but there is only one 48x48 icon. Firefox has six icons.

As you can see, 256px icon is set. If Qt resizes it, tdesktop can't do anything with that.
https://github.com/telegramdesktop/tdesktop/blob/15041368287931e09cac95c36d06eea27626e150/Telegram/SourceFiles/window/main_window.cpp#L301
https://github.com/telegramdesktop/tdesktop/blob/15041368287931e09cac95c36d06eea27626e150/Telegram/SourceFiles/window/main_window.cpp#L109
https://github.com/telegramdesktop/tdesktop/blob/15041368287931e09cac95c36d06eea27626e150/Telegram/SourceFiles/core/application.h#L118-L120
https://github.com/telegramdesktop/tdesktop/blob/15041368287931e09cac95c36d06eea27626e150/Telegram/SourceFiles/core/application.cpp#L100
https://github.com/telegramdesktop/tdesktop/blob/15041368287931e09cac95c36d06eea27626e150/Telegram/SourceFiles/window/main_window.cpp#L52-L54

[bibendi]

I googled more and what I found out.
It's a specific problem of integration Qt applications with KDE.
Here the same issue https://github.com/CDrummond/cantata/issues/1206
And here the workaround https://github.com/CDrummond/cantata/commit/73b48c34894f486241a3dbdba14a7bbfca130a10

[ilya-fedin]

But he just added a 128px png, tdesktop already sets 256px png.

[bibendi]

Ok. I give up. I hope there would be someone more opinionated in Qt than me, who digs deeper into Cantana's master branch and find the workaround. Let's leave this issue open.

[ilya-fedin]

I did some testing. 128x128px icon appears in xprop only with KDE platfromtheme plugin, that can't be used with binary from github. Sorry.

[ilya-fedin]

@Aokromes can you close this as 3rd party bug?

[ilya-fedin]

Looks like I found where Qt bug is placed
https://github.com/qt/qtbase/blob/abfb1b8/src/platformsupport/themes/genericunix/qgenericunixthemes.cpp#L248
https://github.com/KDE/plasma-integration/blob/4a7786999d318759628b9cc3ea1ff963547b561f/src/platformtheme/khintssettings.cpp#L147

[ilya-fedin]

Well, I tried to patch Qt and icon is 48x48 anyway

[ilya-fedin]

Icon is OK on snap
Icon is OK on flatpak
And only static binary is blurred

[ilya-fedin]

Well, I found the root of the problem. It is /usr/share/icons/breeze/apps/48/telegram.svg. KDE developers for some reason provide telegram icon in breeze with 48px size only that overrides telegram's 256px icon. Probably, you should open a bug in KDE bugtracker.

[bibendi]

Thank you so much!

https://bugs.kde.org/show_bug.cgi?id=422253