Set icon theme and button layout for GNOME only if requested

[City-busz]

This ensures that the icon theme and button layout for GNOME applications are not overwritten at login or when changed in the settings if the apply_theme_global setting is disabled. This allows users to decide whether they want COSMIC to modify GNOME settings.

[mmstick]

These shouldn't be gated by the global theme setting. This is needed globally or else window controls and icons won't match. In fact, on a first login, if the icon theme is not set to match the desktop, there will be missing icons in a lot of applications. You'll also see that GTK apps will be missing minimize and maximize buttons even though its the default for COSMIC.

[City-busz]

For the default settings, it's possible to set session-dependent defaults just for the COSMIC session by creating a GSettings override file, e.g. /usr/share/glib-2.0/schemas/30_com.system76.Cosmic.gschema.override with the following content:

[org.gnome.desktop.interface:COSMIC]
icon-theme='Cosmic'

[org.gnome.desktop.wm.preferences:COSMIC]
button-layout=':minimize,maximize,close'

In this way, the default settings will match with COSMIC, but still allows the user to set a custom button layout and icon theme for GTK apps.

[City-busz]

I updated this pull request to include a GSettings override file to match the default settings with COSMIC, so there will be no difference on first login.

[mmstick]

The button layout for window controls and icons should still be kept in sync with modifications made in COSMIC Settings. If you disable the minimize or maximize buttons in COSMIC Settings, that should also be applied to GTK applications. Same for icon themes. The global theme variable is specifically about overriding the GTK4/libadwaita CSS file.

[City-busz]

Why does the global theme variable apply only for setting color-scheme and gtk-theme? The Settings dialog says "Apply this theme to GNOME apps". I would expect that if it's disabled, then no theme settings will be applied for GNOME apps, including the button-layout and icon-theme settings.

Without this, it's impossible to set custom button layout for GTK apps, because it always gets overridden on login.

[City-busz]

Also, the font-name is set only on change by cosmic-settings, and the monospace-font is not saved into GSettings.

Maybe it would better to implement these properties within the Settings portal in xdg-desktop-portal-cosmic. GTK no longer reads GSettings, and relies only on portal: https://gitlab.gnome.org/GNOME/gtk/-/merge_requests/8923

[City-busz]

I opened another pull request: #117

1. This one sets the button layout and icon theme only if apply_theme_global is enabled.
2. That one sets the button layout only if changed, and relies on GSettings override for the initial settings.

Both solutions would be fine for me.