GNOME, GTK4, and libadwaita
GNOME 40 brought a new workflow with horizontal theming and layouts. GNOME 41 built upon this new foundation by introducing the
libadwaita shared library. This library provides the GNOME theming engine. It’s the software layer that gives GNOME the ability to use themes.
The toolkit used to develop the GNOME desktop and native GNOME programs is called GTK. At one time it was an initialism that stood for GIMP ToolKit, but now the name is simply GTK. Well-behaved GTK applications that follow the GNOME human interface guidelines will reference
libadwaita for stylesheets and other theme-centric information.
To harness the power of
libadwaita , applications need to be ported to GTK4. This work started in GNOME 41 and is continued in GNOME 42 with more applications embracing the brave new post-GNOME 40 world. GTK3 applications will still run, but they won’t look as integrated and “native” as GTK4 applications.
For example, GNOME 42 incorporates a new system-wide dark mode setting. To respect that setting, applications will need to be able to access it, and to react accordingly. And that means they’ll need to use the GTK4 toolkit. So there’s a lot of porting to be done.
Bottom line up front, although GNOME 42 might look like another round of small tweaks and polishes, there’s more moving beneath the surface than you’d first imagine. The tide’s turning, and if applications targeting the GNOME desktop want to stay current and relevant, they need to embrace
libadwaita and GTK4.
GNOME 42, Fedora, and Ubuntu
Fedora 36 and Ubuntu 22.04 are going to include GNOME 42. The Canonical developers tailor GNOME to fit in with the Ubuntu look and feel, and their own default layout. Of the two, Fedora is going to give users the closest thing to a plain-vanilla GNOME experience. Because of that, we’re going to look at GNOME in a pre-release version of Fedora 36.
Do bear in mind we’re writing this based on pre-release software and changes are possible between now and GNOME 42’s release.
Improvements in Appearance
Many of the changes to the appearance of GNOME 42 are subtle, and viewed on their own might seem small or pointless, but viewed as a coherent set of changes they bring a modern and crisp look to the desktop. Rounded corners, flat buttons, and visual cues for grouping UI elements are among the changes.
The GNOME status bar uses a brighter white for text and icons, and this higher contrast motif is carried through to other areas such as the “Do Not Disturb” button in the notification and calendar window. The media controls are displayed in a more compact way, leaving more space for the title and artist name.
The little call-out triangle or arrowhead has been removed from the notification and calendar window and the status menu. They now “free-float” without a pointer back to the item that opened them.
Command groupings in applications and menus are shown by a highlighted, round-cornered region. The borders of the highlighted area no longer extend to the edge of the menu.
Not all of the visual tweaks are subtle. The new system-wide light and dark options are located in the “Appearance” pane of the “Settings” app. It’s also where you end up if you right-click the desktop and select “Change Background.”
The default desktop wallpaper comes in two flavors, one brighter than the other. If you select the first option in the “Background” region, the desktop wallpaper automatically switches when you change from light to dark mode or vice versa.
The default light mode wallpaper:
The default dark mode wallpaper:
Of course, the GNOME suite of applications is spearheading the migration to GTK4 and the adoption of
libadwaita, and respecting settings such as the system-wide light and dark mode. However, the changes to the applications aren’t just cosmetic. In some instances, the applications are completely new.
gedit editor is still available, but it’s no longer the default editor. That duty is now performed by a new program called “Text Editor.”
It feels a lot like
gedit, and has many of the same options available in its “Preferences” settings, including highlighting the current line, showing a mini-map of your current file on the right-hand edge of the editor window, and choosing a color scheme.
The new editor neatly shows how an application can be set to follow the system light or dark mode options, or to use its own settings for light and dark mode.
The file browser features refreshed folder icons in a blue gradient color scheme.
Hitting the “PrtSc” key used to take a screenshot of your entire desktop. If you used multiple monitors the captured region included all of them. That was a basic but simple way to take a screenshot. But if you really only wanted a portion of the screen, you needed to subsequently edit the image file to get the result you wanted.
Screenshot now has a user interface. Hitting the “PrtSc” key dims your desktop and places a highlighted rectangle in the middle of the desktop. You can stretch and move this rectangle to cover the region you wish to capture.
If you want to capture the entire desktop click the “Screen” icon, or click the “Window” icon to select a window from the open applications.
A great new feature is the ability to record your screen activity. You can record your desktop, the window of an application, or a selected region. To stop a recording, click the red timer button in the status bar.
This isn’t something that will replace a dedicated screen capture application like OBS Studio but it’s a nice feature to have.
GNOME calculator, GNOMEmaps, GNOME world clocks, and GNOME web browser (Epiphany) have all been ported to GTK4. GNOME software, the application you can use to search for and install software, has been visually refreshed. The carousel of screenshots uses larger images and the descriptions of each application have a “dashboard” format.
Time Will Tell
As we mentioned, we looked at at pre-release software, but we don’t expect too much to change between now and GNOME 42’s release. What might vary from Linux distribution to distribution is how many of the newly-ported GNOME 42 applications are included.
There’s been a lot of code churn to get those applications ported over to GTK4, and code churn makes distribution maintainers nervous. Especially so if the next release of your distribution is a Long Term Support version, like Ubuntu 22.04. Don’t be surprised if some of the newest applications don’t make the cut.
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