Here is the first GTK snapshot of the new development cycle. A lot of things fell into place recently, so it is worth taking some time to go through the details of what is new, and what you can expect to see in 4.12.
List View Improvements
The family of GtkListView, GtkColumnView and GtkGridView widgets was one of the big additions in GTK 4. They are meant to replace GtkTreeView, but up until now, this was clearly still a bit aspirational.
In GTK 4.10, we’ve finally taken the big step to port GtkFileChooser away from tree views—a sign that list views are ready for prime time. And the next GTK 4 release will bring a number of missing features:
- Finally, a fix for the longstanding scrolling bug
- Better keyboard navigation, with customizable tab behavior
- Focus control
- Programmatic scrolling
- Sections, maybe
Some of these are already available in 4.11.1. We even managed to backport the scrolling fix to 4.10.1.
Better Textures
Textures are used frequently in GTKs GL renderer—for icons and images, for glyphs, and for intermediate offscreen rendering. Most of the time, we don’t have to think about them, they just work. But if the texture is the main content of your app, such as in an image viewer, you need a bit more control over it, and it is important that the corner cases work correctly.
In GTK 4.10, we introduced a GskTextureScale node, which gives applications control over the filtering that is applied when scaling a texture up or down. This lets apps request the use of mipmaps with GSK_SCALING_FILTER_TRILINEAR. GTK 4.12 will automatically use mipmaps when it is beneficial.
One corner case that we’ve recently explored is texture slicing. Whenever a texture is bigger than the GL stack supports, GSK will break it into smaller slices and use separate GL textures for each. Modern GPUs support enormous textures (on my system, the max. texture size is 16384), which means that the slicing support is rarely tested in practice and not well covered by our unit tests either.
We added support for artificially limiting the texture size (with the GSK_MAX_TEXTURE_SIZE environment variable), and promptly discovered that our texture slicing support needed some love. It will work much better in 4.12.
Fractional Scaling
It landed on April 1st, but it is not a joke.
We’ve added support for the experimental wp_fractional_scale_manager_v1 protocol to the Wayland backend, and use the wp_viewporter protocol to tell the compositor about the scaling that the buffer is using. It is nice that this was easy to fit into our rendering stack, but don’t expect miracles. It works well with the cairo renderer (as you can see in the video), but we still consider it experimental with the GL and Vulkan renderers.
To try fractional scaling with the GL renderer, set
GDK_DEBUG=gl-fractional
in the environment.
Summary
There’s lots of new things to explore in GTK 4.11. Please try them and let us know what you think, in gitlab or on Discourse.