🥇Wayland-Protocols 1.48 Release

The release of wayland-protocols 1.48 has been announced, containing a set of protocols and extensions that complement the base Wayland protocol and provide functionality necessary for building composite servers and user environments.

In the new version:

The xdg-session-management protocol has been added to the 'staging' category, offering capabilities for restoring the state and position of windows from a disrupted session in Wayland-based environments, for example, after an unexpected termination of a composite server or application.
The capabilities of the text-input protocol have been expanded, allowing composite servers to implement input methods and send text to applications. For example, a no_emoji flag has been added for input without emojis, support for additional actions beyond text insertion has been implemented, a language flag for conveying language information has been added, requests for showing and hiding the input panel have been introduced, and a preedit_hint flag has been added to adjust the style of pre-editing.
An experimental xx-cutouts protocol has been added to obtain information about cutouts on the screen (for example, areas for the front camera on a smartphone screen).
An experimental xx-zones protocol has been introduced for creating and adding top-level windows to 'zones' — environments with their own coordinate space. The protocol allows for a logical arrangement of windows, where each window is positioned relative to another window.
An experimental xx-keyboard-filter protocol has been added for intercepting selected keyboard events by clients, modifying input events, or blocking certain events from being passed to the Wayland surface that has input focus.

All protocols sequentially go through development, testing, and stabilization phases. After the development stage is completed (unstable category), the protocol is placed in the staging branch and officially included in the wayland-protocols set, and after testing is finished, it moves to the stable category. Protocols from the staging category can already be used in composites servers and clients where associated functionality is required. Unlike the unstable category, changes that break compatibility are not allowed in staging, but if issues and shortcomings arise during testing, a significant new version of the protocol or another Wayland extension may replace it.

To speed up the delivery of protocols to developers and encourage early implementation in existing projects, since the last but one release, an 'experimental' phase has been added, which allows changes that break compatibility and the addition of 'raw' protocols that can be gradually refined. While forming a support team and obtaining a certain number of acknowledgments (ACK) from reviewers is required for a protocol to enter the 'staging' phase, it is sufficient to have no objections (NACK) during a two-week review period for it to enter 'experimental'.

The current version of the wayland-protocols set 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.
‘presentation-time’ — provides video display.
«xdg-shell» — an interface for creating and interacting with surfaces as windows, allowing them to be moved around the screen, minimized, maximized, resized, etc.
«linux-dmabuf» — provides capabilities for creating wl_buffers based on DMA-BUF.
"tablet" — input organization from graphic tablets.

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.
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.
security-context — allows identifying clients using sandbox isolation. A client can register a new connection to a composite server based on Wayland and attach a security context to it, after which the composite manager will restrict the capabilities available for the established connection according to the specified security context.
cursor-shape — an alternative way to set the cursor appearance based on transmitting a series of cursor images instead of binding to a surface (wl_surface).
'ext-transient-seat' is designed for creating temporary independent sessions (seats) intended for use with virtual input devices. For instance, when implementing remote desktop connectivity, the protocol allows for creating a separate session with virtual keyboard and mouse for each user.
«xdg-toplevel-drag» — extends the ‘drag & drop’ mechanism by allowing the attachment of top-level windows to the movement operation, which can be used, for example, to organize mouse dragging of toolbars or browser tabs. The new protocol enables the creation of detachable parts of the window that, when dragged out of the original window, become new windows and can be moved above the existing window before reattaching.
«xdg-dialog» — allows assigning top-level surfaces with properties specific to dialog windows, for example, it can create modal dialogs that block user interaction with the rest of the interface.
«linux-drm-syncobj» — provides tools for explicit synchronization of buffers using DRM (Direct Rendering Manager) sync objects. It is expected that in the context of synchronization during rendering to a buffer, the proposed protocol will improve interaction with drivers based on graphical APIs Vulkan and OpenGL (the implementation is based on handlers in the drivers). The new protocol allows ensuring that the rendering operation to the buffer is completed before the composite manager displays this buffer.
alpha-modifier, allowing clients to change the transparency level of the surface and offloading transparency operations to the composite server, which can, in turn, redirect these operations to KMS.
xdg-toplevel-icon — binding an icon to a top-level window.
ext-image-capture-source and ext-image-copy-capture — organizing the capture of content displayed on the screen.
xdg-system-bell — allows the output of a system signal that can be used, for example, as a warning in terminal emulators. The form of the signal output is determined at the discretion of the composite manager; it can be not only sound but also a visual response.
fifo — implements a FIFO mechanism (first-come, first-served) for processing the queue of updates to the displayed surface. Practically, the protocol allows for using vertical synchronization (vblank) waiting instead of callback calls whenever ready to display a new frame, addressing the issue of high GPU load when using VSync.
commit-timing — allows a time constraint to be tied to the surface content (the composite server must display the content change as close to the specified time as possible, but not earlier).
ext-data-control — allows privileged clients to manage data processing, for instance, for clipboard managers.
ext-workspace — implements the concept virtual desktops and offers events with information about the state of the workspaces, as well as features for activating and deactivating workspaces. The protocol can be used to create panels and indicators that display the list of available virtual desktops and allow switching between them.
color-management provides capabilities for color management and support for High Dynamic Range (HDR). With the added extension, client applications can obtain information about color reproduction properties of output devices and transmit data about their own content's color reproduction properties to the composite server. server This information can be used for automatic color management when displaying content on various output devices, for example, to convert content into formats suitable for HDR monitors. ICC profiles are used to describe color spaces.
xdg-toplevel-tag allows Wayland clients to attach tags to top-level surfaces, which the composite server can use to identify windows after the application restarts (for example, the application can set tags "main window" and "settings" for the main and settings windows). Such identification is useful for restoring position, size, and properties of windows after a restart, as well as for applying special rules for certain types of windows.
color-representation defines the color representation of a Wayland surface. Wayland clients can send metadata necessary for defining transparency, color model, subsampling, and quantization range applied when converting buffer data corresponding to the YCbCr color model into RGB representation.
ext-background-effect — applies effects to the translucent parts of a Wayland surface, such as background blur.
pointer-warp — allows an application to instantly move the pointer to a specified position.

Protocols being developed in the 'experimental' branch:

xx-session-management — restoration of window states for interrupted sessions (e.g., after a crash of the composite manager).
xx-input-method allows applications to implement text input methods for composites. servers and to compose the entered text, which can be used, for instance, to create virtual keyboards and IME layers (Input Method Editor) for handling input.
xx-text-input — allows composite servers to implement input methods and send text to applications. The protocol standardizes interaction between the compositor proxy server and applications and enables management of features like text entry transfer, focus change events handling, and consideration of input field specifics (language, text selection, content type).

Protocols being developed in the ‘unstable’ branch:

«fullscreen-shell» — management of fullscreen operation.
«input-method» — processing of input methods.
«idle-inhibit» — prevents the screensaver (screen saver) from starting.
«input-timestamps» — timestamps for input events.
«keyboard-shortcuts-inhibit» — manages the attachment of keyboard shortcuts and hotkeys.
«linux-explicit-synchronization» — Linux-specific buffer synchronization mechanism related to surfaces.
«pointer-gestures» — manages input from touch screens.
«pointer constraints» — pointer restrictions (blocking).
«primary-selection» — similar to X11, enables the primary clipboard (primary selection), where information is typically pasted using the middle mouse button.
«relative pointer events» — relative pointer events.
«text-input» — organization of text input.
«xdg-foreign» — interface for interaction with 'foreign' client surfaces.
«xdg-decoration» — rendering of window decorations on the server side.
«xdg-output» — additional information about video output (used for fractional scaling).
«xwayland-keyboard-grab» — input capture in XWayland applications.

Source: opennet.ru

Release of Wayland-Protocols 1.48