Wayland 1.18 arrives with meson support, new API and more

Recently the release of the new stable version of the Wayland 1.18 protocol was announced, in which this new version is compatible with previous versions at the API and ABI level with versions 1.x, but also contains a part of the improvements.

For those unaware of Wayland, they should know that this is a protocol for the interaction of a composite server and the applications that work with it. Clients independently render their windows separately, passing update information to a composite server, which combines the contents of individual application windows to form the final output, taking into account possible nuances such as window overlap and transparency.

In other words, a composite server does not provide an API for rendering individual elements and operates only with the windows already formed eliminating double buffering using high-level libraries such as GTK + and Qt.

About Wayland

Currently, the support for direct work with Wayland is already implemented for GTK3 +, Qt 5, SDL, Clutter and EFL (Enlightenment Foundation Library).

Interaction with hardware in Wayland / Weston, for example, the initialization, changing video modes (drm mode setting) and memory management (GEM for i915 and TTM for radeon and nouveau) of graphics cards, can be done directly through a kernel-level module, which allows you to bypass superuser privileges.

Weston composite server can work not only using Linux kernel DRM module, but also on X11, other Wayland composite server, framebuffer and RDP. Additionally, projects are being developed to ensure work at the top of the Android platform graphics stack.

As part of the Weston project, one of the composite server implementations is being developed.

Any other product that supports the Wayland protocol can also act as a composite server.

For example, work is currently underway to provide support to Wayland at KWin. In its current form, Weston has already gone beyond the scope of a set of samples to test the Wayland protocol and can acquire functionality through plugins. In addition, it is proposed to implement custom shells and advanced window management functions in the form of backends external to Weston.

To ensure the running of ordinary X11 applications in a Wayland-based environment, the XWayland DDX (Device Dependent X) component is used, which is similar in organization to working in Xwin and Xquartz for Win32 and OS X platforms.

X11 application release support is planned to be integrated directly into the Weston composite server, which when it comes to the full X11 application - will initiate the release of the X server and related XWayland components.

With this approach, the process of launching X11 applications will be straightforward and indistinguishable for the user of launching applications that work directly with Wayland.

Major improvements in Wayland 1.18

Of its novelties, the announcement mentions whate added support for the Meson building system, while the ability to build using autotools is still preserved, but will be removed in a future release.

Another change that stands out in this new version of Wayland 1.18 is the new API added to separate proxy objects tag-based. This allows applications and toolkits to share a Wayland connection.

In addition, added wl_global_remove () function which dispatches a global object delete event without cleaning it up.

The new feature allows to eliminate the occurrence of the "race condition" when eliminating global objects. Similar race conditions could occur because customers were unable to confirm receipt of the elimination event. The wl_global_remove () function makes it possible to send a delete event first and only after a certain delay does it delete the object.

As well wayland server timers tracked guaranteed in user space, eliminating the creation of too many file descriptors.