It has been a month since we released GTK 3.99, high time for another snapshot. Here it is: https://download.gnome.org/sources/gtk/3.99/gtk-3.99.1.tar.xz
This snapshot is focused on polish and completion.
We’ve tied up a number of loose ends in our APIs.
The most user-visible change was probably the simplification of the button class hierarchy. Instead of deriving GtkCheckButton from GtkToggleButton, they are now two independent widgets, and they both can be grouped to be mutually exclusive (aka as “radio group”). In this new setup, GtkRadioButton is not really needed anymore, and therefore gone.
The API of our new list widgets (GtkListView and GtkGridView) has seen some small tweaks as well. We are now explicitly requiring the models to be of type GtkSelectionModel, to make it clear that the widgets handle selections. And we’ve gotten rid of the extra “with_factory” constructors, and just take a nullable factory argument in new(), leaving us with
GtkWidget * gtk_list_view_new (GtkSelectionModel *model, GtkListItemFactory *factory);
As more of an API cleanup, we’ve dropped all the defines for CSS style classes – which style classes our widgets support is defined in their documentation, and these extra defines were not really well-defined or useful.
Our theme is now rounding the corners of the frame that is drawn by GtkFrame widgets. This required us to make frames clip their children – not really an API change, but a behavior change that is worth mentioning.
A lot of effort has gone into gtk4-demo over the past month.
We have modernized the source code highlighting. We are now using the highlight commandline utility. Among other things, this allows us to have syntax highlighting for xml and css, as well as dark theme support.
The list of demos has better filtering and a better appearance. The new look is one of a few predefined list styles that Adwaita supports now: rich list, navigation sidebar and data table.
We have dropped a few outdated demos from gtk4-demo, and polished many of the existing ones. Here is how our Drag-and-Drop demo looks now:
A number of new demos have been added as well. Here is the new demo for layout managers and transformations:
Performance, and other bugs
Many bugs have been squashed; thanks to our eager testers and bug reporters.
A long-standing issue that we finally tracked down recently caused our GL renderer to get clipping wrong in the presence of non-trivial projective transformations. This has now been corrected (and the result can be seen in the transformation demo above).
As part of the highlighting improvements that have been mentioned before, gtk_text_view_buffer_insert_markup() has been made much faster. This improvement only happened because the highlight utility can produce Pango markup. Kudos to whoever implemented that!
Another performance problem that we’ve addressed is the loading time of the font chooser dialog on systems with many fonts. We are now populating the font list incrementally. Apart from this change, the investigation has led to performance improvements in fontconfig and Pango that will benefit any user of those libraries.
Can I port already?
The answer is: yes!
Now is a great time to take a look at GTK4, start porting your app, and give us feedback on our APIs, new and old. We are also eager to see what ideas you have for using GTK4 in unexpected ways – the few demos we’ve shown above can maybe give you some inspiration.
We are looking to land the at-spi backend for our new accessibility interfaces soon; it should be included in the next GTK snapshot.