GTK 4 used only 48x48 application icon that leads to fuzzy icons. GTK2 works fine

[ebassi (Emmanuele Bassi)]

@Nilsou

I was talking about the icon used when you open the application, the icon in the taskbar. As far as I understand, this icon is defined via the “gtk_window_set_icon_name” function , not by the .desktop.

No, in GNOME Shell the icon is determined by the desktop file at all times. The icon set using gtk_window_set_icon_name() can only be used in X11, and it’s only looked at as a fallback there.

In order:

1. the icon in the desktop file
2. if the icon is missing, and you’re on X11, use the icon set with gtk_window_set_icon_name()
3. if the icon is missing, use the icon name set using gtk_window_set_default_icon_name().

In all of these cases, you need the icon to be a named one, which means adding it to the icon theme.

Without having access to your code, my assumption is that what you’re seeing is the desktop trying to upscale an icon set using gtk_window_set_icon_name(). You should provide a high resolution icon, or at least a scalable icon in your desktop file.