The release of the wayland-protocols package 1.31 has been published, containing a set of protocols and extensions that enhance the capabilities of the base Wayland protocol and provide the necessary features for building composite servers and user environments.
All protocols go through three phases: development, testing, and stabilization. After the development stage (the 'unstable' category) is completed, the protocol is moved to the 'staging' branch and officially included in the wayland-protocols set, and after testing is completed, it is moved to the stable category. Protocols in the 'staging' category can already be used in composite servers and clients where the related functionality is required. Unlike the 'unstable' category, changes that break compatibility are prohibited in 'staging', but if issues and deficiencies are identified during testing, the replacement of the protocol with a significant new version or another Wayland extension is not excluded.
The new version was released a week after the Wayland-Protocols 1.30, which added support for the tearing-control protocol to disable vertical synchronization. Version 1.31 introduces the fractional-scale protocol in the 'staging' category, allowing the compositor to transmit fractional scaling values for surfaces, enabling the client to determine a more precise size for buffers of wp_viewport objects compared to passing rounded scaling information. Implementations of the fractional-scale protocol are prepared for wlroots, KWin, and glfw.
Currently, the wayland-protocols package includes the following stable protocols that ensure backward compatibility:
- viewporter - allows the client to perform scaling and cropping actions on the surface from the client's side. server.
- âpresentation-timeâ â provides video display.
- âxdg-shellâ â an interface for creating and interacting with surfaces as windows, allowing them to be moved across the screen, minimized, maximized, resized, etc.
Protocols currently being tested in the 'staging' branch:
- drm-lease provides the resources necessary for forming a stereo image with different buffers for the left and right eye when outputting to virtual reality headsets.
- ext-session-lock defines session lock mechanisms, such as during the screensaver operation or the display of an authentication dialog.
- single-pixel-buffer allows the creation of single-pixel buffers that include four 32-bit RGBA values.
- xdg-activation enables focus transfer between different top-level surfaces (for example, using xdg-activation, one application can shift focus to another).
- content-type allows clients to convey information about the displayed content that can be used to optimize behavior based on content, such as setting specific DRM properties like 'content type'. Support is declared for the following content types: none (no information about data type), photo (output of digital photos requiring minimal processing), video (video or animation requiring more precise synchronization to avoid stuttering), and game (launching games requiring output with minimal latency). server ext-idle-notify allows composite servers to send notifications to clients about user inactivity, which can be used to activate additional power-saving modes after a certain period of inactivity.
- tearing-control allows disabling vertical synchronization (VSync) with frame-destroying pulse in fullscreen applications, used to prevent tearing during output. In multimedia applications, the appearance of artifacts due to tearing is an undesirable effect, but in gaming programs, artifacts can be tolerated if combating them leads to additional delays.
- ext-foreign-toplevel-list retrieves information about surfaces positioned at the very top level (toplevel) that allow the organization of window pinning over other content, for example, to connect custom panels and window switches.
Protocols being developed in the âunstableâ branch:
- «fullscreen-shell» â management of fullscreen operation.
- «input-method» â processing of input methods.
- «idle-inhibit» â prevents the screensaver (screen saver) from starting.
- «input-timestamps» â timestamps for input events.
- «keyboard-shortcuts-inhibit» â manages the attachment of keyboard shortcuts and hotkeys.
- linux-dmabuf - enables sharing multiple graphics cards using dma-buf technology.
- «linux-explicit-synchronization» â Linux-specific buffer synchronization mechanism related to surfaces.
- «pointer-gestures» â manages input from touch screens.
- «pointer constraints» â pointer restrictions (blocking).
- «primary-selection» â similar to X11, enables the primary clipboard (primary selection), where information is typically pasted using the middle mouse button.
- «relative pointer events» â relative pointer events.
- tablet - support for input from tablets.
- «text-input» â organization of text input.
- «xdg-foreign» â interface for interaction with 'foreign' client surfaces.
- «xdg-decoration» â rendering of window decorations on the server side.
- «xdg-output» â additional information about video output (used for fractional scaling).
- «xwayland-keyboard-grab» â input capture in XWayland applications.
Source: opennet.ru
