Foreign toplevel list

List toplevels

The purpose of this protocol is to provide protocol object handles for toplevels, possibly originating from another client.

This protocol is intentionally minimalistic and expects additional functionality (e.g. creating a screencopy source from a toplevel handle, getting information about the state of the toplevel) to be implemented in extension protocols.

The compositor may choose to restrict this protocol to a special client launched by the compositor itself or expose it to all clients, this is compositor policy.

The key words "must", "must not", "required", "shall", "shall not", "should", "should not", "recommended", "may", and "optional" in this document are to be interpreted as described in IETF RFC 2119.

Warning! The protocol described in this file is currently in the testing phase. Backward compatible changes may be added together with the corresponding interface version bump. Backward incompatible changes can only be done by creating a new major version of the extension.

List toplevels

A toplevel is defined as a surface with a role similar to xdg_toplevel. XWayland surfaces may be treated like toplevels in this protocol.

After a client binds the ext_foreign_toplevel_list_v1, each mapped toplevel window will be sent using the ext_foreign_toplevel_list_v1.toplevel event.

Clients which only care about the current state can perform a roundtrip after binding this global.

For each instance of ext_foreign_toplevel_list_v1, the compositor must create a new ext_foreign_toplevel_handle_v1 object for each mapped toplevel.

If a compositor implementation sends the ext_foreign_toplevel_list_v1.finished event after the global is bound, the compositor must not send any ext_foreign_toplevel_list_v1.toplevel events.

stop()
Stop sending events

This request indicates that the client no longer wishes to receive events for new toplevels.

The Wayland protocol is asynchronous, meaning the compositor may send further toplevel events until the stop request is processed. The client should wait for a ext_foreign_toplevel_list_v1.finished event before destroying this object.

destroy()
Destroy the ext_foreign_toplevel_list_v1 object

This request should be called either when the client will no longer use the ext_foreign_toplevel_list_v1 or after the finished event has been received to allow destruction of the object.

If a client wishes to destroy this object it should send a ext_foreign_toplevel_list_v1.stop request and wait for a ext_foreign_toplevel_list_v1.finished event, then destroy the handles and then this object.

Argument
Type
Description
toplevelnew_id<ext_foreign_toplevel_handle_v1>
A toplevel has been created

This event is emitted whenever a new toplevel window is created. It is emitted for all toplevels, regardless of the app that has created them.

All initial properties of the toplevel (identifier, title, app_id) will be sent immediately after this event using the corresponding events for ext_foreign_toplevel_handle_v1. The compositor will use the ext_foreign_toplevel_handle_v1.done event to indicate when all data has been sent.

finished()
The compositor has finished with the toplevel manager

This event indicates that the compositor is done sending events to this object. The client should should destroy the object. See ext_foreign_toplevel_list_v1.destroy for more information.

The compositor must not send any more toplevel events after this event.


A mapped toplevel

A ext_foreign_toplevel_handle_v1 object represents a mapped toplevel window. A single app may have multiple mapped toplevels.

destroy()
Destroy the ext_foreign_toplevel_handle_v1 object

This request should be used when the client will no longer use the handle or after the closed event has been received to allow destruction of the object.

When a handle is destroyed, a new handle may not be created by the server until the toplevel is unmapped and then remapped. Destroying a toplevel handle is not recommended unless the client is cleaning up child objects before destroying the ext_foreign_toplevel_list_v1 object, the toplevel was closed or the toplevel handle will not be used in the future.

Other protocols which extend the ext_foreign_toplevel_handle_v1 interface should require destructors for extension interfaces be called before allowing the toplevel handle to be destroyed.

closed()
The toplevel has been closed

The server will emit no further events on the ext_foreign_toplevel_handle_v1 after this event. Any requests received aside from the destroy request must be ignored. Upon receiving this event, the client should destroy the handle.

Other protocols which extend the ext_foreign_toplevel_handle_v1 interface must also ignore requests other than destructors.

done()
All information about the toplevel has been sent

This event is sent after all changes in the toplevel state have been sent.

This allows changes to the ext_foreign_toplevel_handle_v1 properties to be atomically applied. Other protocols which extend the ext_foreign_toplevel_handle_v1 interface may use this event to also atomically apply any pending state.

This event must not be sent after the ext_foreign_toplevel_handle_v1.closed event.

title(title: string)
Argument
Type
Description
titlestring
Title change

The title of the toplevel has changed.

The configured state must not be applied immediately. See ext_foreign_toplevel_handle_v1.done for details.

app_id(app_id: string)
Argument
Type
Description
app_idstring
App_id change

The app id of the toplevel has changed.

The configured state must not be applied immediately. See ext_foreign_toplevel_handle_v1.done for details.

identifier(identifier: string)
Argument
Type
Description
identifierstring
A stable identifier for a toplevel

This identifier is used to check if two or more toplevel handles belong to the same toplevel.

The identifier is useful for command line tools or privileged clients which may need to reference an exact toplevel across processes or instances of the ext_foreign_toplevel_list_v1 global.

The compositor must only send this event when the handle is created.

The identifier must be unique per toplevel and it's handles. Two different toplevels must not have the same identifier. The identifier is only valid as long as the toplevel is mapped. If the toplevel is unmapped the identifier must not be reused. An identifier must not be reused by the compositor to ensure there are no races when sharing identifiers between processes.

An identifier is a string that contains up to 32 printable ASCII bytes. An identifier must not be an empty string. It is recommended that a compositor includes an opaque generation value in identifiers. How the generation value is used when generating the identifier is implementation dependent.


Compositor Support

No compositor support found

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