Input method v2

Protocol for creating input methods

This protocol allows applications to act as input methods for compositors.

An input method context is used to manage the state of the input method.

Text strings are UTF-8 encoded, their indices and lengths are in bytes.

This document adheres to the RFC 2119 when using words like "must", "should", "may", etc.

Warning! The protocol described in this file is currently in the experimental phase. Backwards incompatible major versions of the protocol are to be expected. Exposing this protocol without an opt-in mechanism is discouraged.

input method

An input method object allows for clients to compose text.

The objects connects the client to a text input in an application, and lets the client to serve as an input method for a seat.

The xx_input_method_v1 object can occupy two distinct states: active and inactive. In the active state, the object is associated to and communicates with a text input. In the inactive state, there is no associated text input, and the only communication is with the compositor. Initially, the input method is in the inactive state.

Requests issued in the inactive state must be accepted by the compositor. Because of the serial mechanism, and the state reset on activate event, they will not have any effect on the state of the next text input.

There must be no more than one input method object per seat.

commit_string(text: string)
Argument
Type
Description
textstring
commit string

Send the commit string text for insertion to the application.

Inserts a string at current cursor position (see commit event sequence). The string to commit could be either just a single character after a key press or the result of some composing.

The argument text is a buffer containing the string to insert. There is a maximum length of wayland messages, so text can not be longer than 4000 bytes.

Values set with this event are double-buffered. They must be applied and reset to initial on the next zwp_text_input_v3.commit request.

The initial value of text is an empty string.

set_preedit_string(text: string, cursor_begin: int, cursor_end: int)
Argument
Type
Description
textstring
cursor_beginint
cursor_endint
pre-edit string

Send the pre-edit string text to the application text input.

Place a new composing text (pre-edit) at the current cursor position. Any previously set composing text must be removed. Any previously existing selected text must be removed. The cursor is moved to a new position within the preedit string.

The argument text is a buffer containing the preedit string. There is a maximum length of wayland messages, so text can not be longer than 4000 bytes.

The arguments cursor_begin and cursor_end are counted in bytes relative to the beginning of the submitted string buffer. Cursor should be hidden by the text input when both are equal to -1.

cursor_begin indicates the beginning of the cursor. cursor_end indicates the end of the cursor. It may be equal or different than cursor_begin.

Values set with this event are double-buffered. They must be applied on the next xx_input_method_v1.commit event.

The initial value of text is an empty string. The initial value of cursor_begin, and cursor_end are both 0.

delete_surrounding_text(before_length: uint, after_length: uint)
Argument
Type
Description
before_lengthuint
after_lengthuint
delete text

Remove the surrounding text.

before_length and after_length are the number of bytes before and after the current cursor index (excluding the preedit text) to delete.

If any preedit text is present, it is replaced with the cursor for the purpose of this event. In effect before_length is counted from the beginning of preedit text, and after_length from its end (see commit event sequence).

Values set with this event are double-buffered. They must be applied and reset to initial on the next xx_input_method_v1.commit request.

The initial values of both before_length and after_length are 0.

commit(serial: uint)
Argument
Type
Description
serialuint
apply state

Apply state changes from commit_string, set_preedit_string and delete_surrounding_text requests.

The state relating to these events is double-buffered, and each one modifies the pending state. This request replaces the current state with the pending state.

The connected text input is expected to proceed by evaluating the changes in the following order:

1. Replace existing preedit string with the cursor. 2. Delete requested surrounding text. 3. Insert commit string with the cursor at its end. 4. Calculate surrounding text to send. 5. Insert new preedit text in cursor position. 6. Place cursor inside preedit text.

The serial number reflects the last state of the xx_input_method_v1 object known to the client. The value of the serial argument must be equal to the number of done events already issued by that object. When the compositor receives a commit request with a serial different than the number of past done events, it must proceed as normal, except it should not change the current state of the xx_input_method_v1 object.

destroy()
destroy the text input

Destroys the zwp_text_input_v2 object and any associated child objects.

activate()
input method has been requested

Notification that a text input focused on this seat requested the input method to be activated.

This event serves the purpose of providing the compositor with an active input method.

This event resets all state associated with previous enable, disable, surrounding_text, text_change_cause, and content_type events, as well as the state associated with set_preedit_string, commit_string, and delete_surrounding_text requests. In addition, it marks the xx_input_method_v1 object as active, and makes any existing zwp_input_popup_surface_v2 objects visible.

The surrounding_text, and content_type events must follow before the next done event if the text input supports the respective functionality.

State set with this event is double-buffered. It will get applied on the next xx_input_method_v1.done event, and stay valid until changed.

deactivate()
deactivate event

Notification that no focused text input currently needs an active input method on this seat.

This event marks the xx_input_method_v1 object as inactive. The compositor must make all existing zwp_input_popup_surface_v2 objects invisible until the next activate event.

State set with this event is double-buffered. It will get applied on the next xx_input_method_v1.done event, and stay valid until changed.

surrounding_text(text: string, cursor: uint, anchor: uint)
Argument
Type
Description
textstring
cursoruint
anchoruint
surrounding text event

Updates the surrounding plain text around the cursor, excluding the preedit text.

If any preedit text is present, it is replaced with the cursor for the purpose of this event.

The argument text is a buffer containing the preedit string, and must include the cursor position, and the complete selection. It should contain additional characters before and after these. There is a maximum length of wayland messages, so text can not be longer than 4000 bytes.

cursor is the byte offset of the cursor within the text buffer.

anchor is the byte offset of the selection anchor within the text buffer. If there is no selected text, anchor must be the same as cursor.

If this event does not arrive before the first done event, the input method may assume that the text input does not support this functionality and ignore following surrounding_text events.

Values set with this event are double-buffered. They will get applied and set to initial values on the next xx_input_method_v1.done event.

The initial state for affected fields is empty, meaning that the text input does not support sending surrounding text. If the empty values get applied, subsequent attempts to change them may have no effect.

text_change_cause(cause: uint<zwp_text_input_v3.change_cause>)
Argument
Type
Description
causeuint<zwp_text_input_v3.change_cause>
indicates the cause of surrounding text change

Tells the input method why the text surrounding the cursor changed.

Whenever the client detects an external change in text, cursor, or anchor position, it must issue this request to the compositor. This request is intended to give the input method a chance to update the preedit text in an appropriate way, e.g. by removing it when the user starts typing with a keyboard.

cause describes the source of the change.

The value set with this event is double-buffered. It will get applied and set to its initial value on the next xx_input_method_v1.done event.

The initial value of cause is input_method.

content purpose and hint

Indicates the content type and hint for the current xx_input_method_v1 instance.

Values set with this event are double-buffered. They will get applied on the next xx_input_method_v1.done event.

The initial value for hint is none, and the initial value for purpose is normal.

done()
apply state

Atomically applies state changes recently sent to the client.

The done event establishes and updates the state of the client, and must be issued after any changes to apply them.

Text input state (content purpose, content hint, surrounding text, and change cause) is conceptually double-buffered within an input method context.

Events modify the pending state, as opposed to the current state in use by the input method. A done event atomically applies all pending state, replacing the current state. After done, the new pending state is as documented for each related request.

Events must be applied in the order of arrival.

Neither current nor pending state are modified unless noted otherwise.

unavailable()
input method unavailable

The input method ceased to be available.

The compositor must issue this event as the only event on the object if there was another input_method object associated with the same seat at the time of its creation.

The compositor must issue this request when the object is no longer useable, e.g. due to seat removal.

The input method context becomes inert and should be destroyed after deactivation is handled. Any further requests and events except for the destroy request must be ignored.


input method manager

The input method manager allows the client to become the input method on a chosen seat.

No more than one input method must be associated with any seat at any given time.

get_input_method(seat: object<wl_seat>, input_method: new_id<xx_input_method_v1>)
Argument
Type
Description
seatobject<wl_seat>
input_methodnew_id<xx_input_method_v1>
request an input method object

Request a new input xx_input_method_v1 object associated with a given seat.

destroy()
destroy the input method manager

Destroys the zwp_input_method_manager_v2 object.

The xx_input_method_v1 objects originating from it remain valid.


Compositor Support

No compositor support found

Copyright © 2008-2011 Kristian Høgsberg Copyright © 2010-2011 Intel Corporation Copyright © 2012-2013 Collabora, Ltd. Copyright © 2012, 2013 Intel Corporation Copyright © 2015, 2016 Jan Arne Petersen Copyright © 2017, 2018 Red Hat, Inc. Copyright © 2018 Purism SPC

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