[PATCHv4 wayland-protocols] text-input: Add v3 of the text-input protocol
Silvan Jegen
s.jegen at gmail.com
Thu May 3 18:47:27 UTC 2018
Hi Dorota
Some comments and typo fixes below.
On Thu, May 03, 2018 at 05:41:21PM +0200, Dorota Czaplejewicz wrote:
> This new protocol description is a simplification over v2.
>
> - All pre-edit text styling is gone.
> - Pre-edit cursor can span characters.
> - No events regarding input panel (OSK) state nor covered rectangle.
> Compositors are still free to handle situations where the keyboard
> focus rectangle is covered by the input panel.
> - No set_preferred_language request for clients.
> - There is no event to send keysyms. Compositors can use wl_keyboard
> interface instead.
> - All state is double-buffered, with specified state.
> - Use Unicode codepoints to measure strings.
>
> Signed-off-by: Dorota Czaplejewicz <dorota.czaplejewicz at puri.sm>
> Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
> ---
> This is the next update coming from Purism to perfect the text input protocol.
>
> The following changes added on top of PATCHv3:
>
> - Fixed whitespaces.
> - Removed enable flags - the same information can be gathered from the first requests after enter.
> - Changed offsets inside UTF-8 strings to use Unicode character counts in order to remove the possibility of communicating invalid state.
> - Specified the exact lifetime of double-buffered state, and initial values.
> - Made changes requested by the IM double-buffered.
>
> Some questions remain open. One is: how to specify how much text to capture in set_surrounding_text, and how often to update?
>
> A possible change that I decided against for now is to replace enable/disable events by create/destroy of a new object, which would make more state lifetimes encoded in the protocol.
>
> After reading a blog post on fcitx [0], I got the impression that letting the compositor know some persistent ID of a text edit instance could be useful, however I'm not sure what the use cases are.
>
> As always, I'm happy to hear feedback.
>
> Cheers,
> Dorota Czaplejewicz
>
> [0] https://www.csslayer.info/wordpress/fcitx-dev/gaps-between-wayland-and-fcitx-or-all-input-methods/
>
> Makefile.am | 1 +
> unstable/text-input/text-input-unstable-v3.xml | 362 +++++++++++++++++++++++++
> 2 files changed, 363 insertions(+)
> create mode 100644 unstable/text-input/text-input-unstable-v3.xml
>
> diff --git a/Makefile.am b/Makefile.am
> index 4b9a901..86d7ca9 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -3,6 +3,7 @@ unstable_protocols = \
> unstable/fullscreen-shell/fullscreen-shell-unstable-v1.xml \
> unstable/linux-dmabuf/linux-dmabuf-unstable-v1.xml \
> unstable/text-input/text-input-unstable-v1.xml \
> + unstable/text-input/text-input-unstable-v3.xml \
> unstable/input-method/input-method-unstable-v1.xml \
> unstable/xdg-shell/xdg-shell-unstable-v5.xml \
> unstable/xdg-shell/xdg-shell-unstable-v6.xml \
> diff --git a/unstable/text-input/text-input-unstable-v3.xml b/unstable/text-input/text-input-unstable-v3.xml
> new file mode 100644
> index 0000000..ed5204f
> --- /dev/null
> +++ b/unstable/text-input/text-input-unstable-v3.xml
> @@ -0,0 +1,362 @@
> +<?xml version="1.0" encoding="UTF-8"?>
> +
> +<protocol name="text_input_unstable_v3">
> + <copyright>
> + Copyright © 2012, 2013 Intel Corporation
> + Copyright © 2015, 2016 Jan Arne Petersen
> + Copyright © 2017, 2018 Red Hat, Inc.
> + Copyright © 2018 Purism SPC
> +
> + Permission to use, copy, modify, distribute, and sell this
> + software and its documentation for any purpose is hereby granted
> + without fee, provided that the above copyright notice appear in
> + all copies and that both that copyright notice and this permission
> + notice appear in supporting documentation, and that the name of
> + the copyright holders not be used in advertising or publicity
> + pertaining to distribution of the software without specific,
> + written prior permission. The copyright holders make no
> + representations about the suitability of this software for any
> + purpose. It is provided "as is" without express or implied
> + warranty.
> +
> + THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
> + SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
> + FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
> + SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
> + WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN
> + AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION,
> + ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
> + THIS SOFTWARE.
> + </copyright>
> +
> + <interface name="zwp_text_input_v3" version="1">
> + <description summary="text input">
> + The zwp_text_input_v3 interface represents text input and input methods
> + associated with a seat. It provides enter/leave events to follow the
> + text input focus for a seat.
> +
> + Requests are used to enable/disable the text-input object and set
> + state information like surrounding and selected text or the content type.
> + The information about the entered text is sent to the text-input object
> + via the pre-edit and commit_string events.
> +
> + Text is valid UTF-8 encoded, indices and lengths are in code points. If a
> + grapheme is made up of multiple code points, an index pointing to any of
> + them should be interpreted as pointing to the first one.
That way we make sure we don't put the cursor/anchor between bytes that
belong to the same UTF-8 encoded Unicode code point which is nice. It
also means that the client has to parse all the UTF-8 encoded strings
into Unicode code points up to the desired cursor/anchor position
on each "preedit_string" event. For each "delete_surrounding_text" event
the client has to parse the UTF-8 sequences before and after the cursor
position up to the requested Unicode code point.
I feel like we are processing the UTF-8 string already in the
input-method. So I am not sure that we should parse it again on the
client side. Parsing it again would also mean that the client would need
to know about UTF-8 which would be nice to avoid.
Thoughts?
> +
> + Focus moving throughout surfaces will result in the emission of
> + zwp_text_input_v3.enter and zwp_text_input_v3.leave events. The focused
> + surface must perform zwp_text_input_v3.enable and
> + zwp_text_input_v3.disable requests as the keyboard focus moves across
> + editable and non-editable elements of the UI. Those two requests are not
> + expected to be paired with each other, the compositor must be able to
> + handle consecutive series of the same request.
> +
> + State is sent by the state requests (set_surrounding_text,
> + set_content_type and set_cursor_rectangle) and a commit request.
> + After an enter event or disable request all state information is
> + invalidated and needs to be resent by the client.
> +
> + This protocol defines requests and events necessary for regular clients
> + to communicate with an input method. The zwp_input_method protocol
> + defines the interfaces necessary to implement standalone input methods.
> + If a compositor implements both interfaces, it will be the arbiter of the
> + communication between both.
> +
> + Warning! The protocol described in this file is experimental and
> + backward incompatible changes may be made. Backward compatible changes
> + may be added together with the corresponding interface version bump.
> + Backward incompatible changes are done by bumping the version number in
> + the protocol and interface names and resetting the interface version.
> + Once the protocol is to be declared stable, the 'z' prefix and the
> + version number in the protocol and interface names are removed and the
> + interface version number is reset.
> + </description>
> +
> + <request name="destroy" type="destructor">
> + <description summary="Destroy the wp_text_input">
> + Destroy the wp_text_input object. Also disables all surfaces enabled
> + through this wp_text_input object.
> + </description>
> + </request>
> +
> + <request name="enable">
> + <description summary="Request text input to be enabled">
> + Requests text input. This request should be issued every time the
> + active text input changes, including within one surface.
> +
> + This request resets all state associated with previous enable,
> + set_surrounding_text, set_content_type, and set_cursor_rectangle
> + requests, as well as the state associated with preedit_string,
> + commit_string, and delete_surrounding_text events.
> +
> + The set_surrounding_text, set_content_type and set_cursor_rectangle
> + requests should follow if the text input supports the necessary
> + functionality.
> +
> + The changes must be applied by the compositor after issuing a
> + zwp_text_input_v3.commit request.
> + </description>
> + </request>
> +
> + <request name="disable">
> + <description summary="Disable text input on a surface">
> + Explicitly disable text input in a surface (typically when there is no
> + focus on any text entry inside the surface).
> + </description>
> + </request>
> +
> + <request name="set_surrounding_text">
> + <description summary="sets the surrounding text">
> + Sets the surrounding plain text around the input position.
> +
> + Text is UTF-8 encoded. Cursor is the Unicode code point offset within
> + the surrounding text.
> + Anchor is the Unicode code point offset of the selection anchor within
> + the surrounding text. If there is no selected text, anchor is the same
> + as cursor.
> +
> + If the client is unaware of the text around the cursor, it should not
> + issue this request, to signify lack of support to the compositor.
> +
> + There is a maximum length of wayland messages so text can not be
> + longer than 4000 bytes.
> +
> + Values set with this request are double-buffered. They will get applied
> + on the next zwp_text_input_v3.commit request, and stay valid until the
> + next enable or disable request.
> +
> + 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.
> + </description>
> + <arg name="text" type="string"/>
> + <arg name="cursor" type="int"/>
> + <arg name="anchor" type="int"/>
> + </request>
> +
> + <enum name="content_hint" bitfield="true">
> + <description summary="content hint">
> + Content hint is a bitmask to allow to modify the behavior of the text
> + input.
> + </description>
> + <entry name="none" value="0x0" summary="no special behavior"/>
> + <entry name="completion" value="0x1" summary="suggest word completions"/>
> + <entry name="spellcheck" value="0x2" summary="suggest word corrections"/>
> + <entry name="auto_capitalization" value="0x4" summary="switch to uppercase letters at the start of a sentence"/>
> + <entry name="lowercase" value="0x8" summary="prefer lowercase letters"/>
> + <entry name="uppercase" value="0x10" summary="prefer uppercase letters"/>
> + <entry name="titlecase" value="0x20" summary="prefer casing for titles and headings (can be language dependent)"/>
> + <entry name="hidden_text" value="0x40" summary="characters should be hidden"/>
> + <entry name="sensitive_data" value="0x80" summary="typed text should not be stored"/>
> + <entry name="latin" value="0x100" summary="just Latin characters should be entered"/>
> + <entry name="multiline" value="0x200" summary="the text input is multiline"/>
> + </enum>
> +
> + <enum name="content_purpose">
> + <description summary="content purpose">
> + The content purpose allows to specify the primary purpose of a text
> + input.
> +
> + This allows an input method to show special purpose input panels with
> + extra characters or to disallow some characters.
> + </description>
> + <entry name="normal" value="0" summary="default input, allowing all characters"/>
> + <entry name="alpha" value="1" summary="allow only alphabetic characters"/>
> + <entry name="digits" value="2" summary="allow only digits"/>
> + <entry name="number" value="3" summary="input a number (including decimal separator and sign)"/>
> + <entry name="phone" value="4" summary="input a phone number"/>
> + <entry name="url" value="5" summary="input an URL"/>
> + <entry name="email" value="6" summary="input an email address"/>
> + <entry name="name" value="7" summary="input a name of a person"/>
> + <entry name="password" value="8" summary="input a password (combine with sensitive_data hint)"/>
> + <entry name="pin" value="9" summary="input is a numeric password (combine with sensitive_data hint)"/>
> + <entry name="date" value="10" summary="input a date"/>
> + <entry name="time" value="11" summary="input a time"/>
> + <entry name="datetime" value="12" summary="input a date and time"/>
> + <entry name="terminal" value="13" summary="input for a terminal"/>
> + </enum>
> +
> + <request name="set_content_type">
> + <description summary="set content purpose and hint">
> + Sets the content purpose and content hint. While the purpose is the
> + basic purpose of an input field, the hint flags allow to modify some
> + of the behavior.
> +
> + Values set with this request are double-buffered. They will get applied
> + on the first zwp_text_input_v3.commit request after an enabl request.
s/enabl/enable/
> + Subsequent attempts to update them may have no effect. The values
> + remain valid until the next enable or disable request.
> +
> + The initial value for hint is none, and the initial value for purpose
> + is normal.
> + </description>
> + <arg name="hint" type="uint" enum="content_hint"/>
> + <arg name="purpose" type="uint" enum="content_purpose"/>
> + </request>
> +
> + <request name="set_cursor_rectangle">
> + <description summary="set cursor position">
> + Marks an area around the cursor as a x, y, width, height rectangle in surface
> + local coordinates.
> +
> + Allows the compositor to put a window with word suggestions near the
> + cursor, without obstructing the text being input.
> +
> + If the client is unaware of the position of edited text, it should not
> + issue this request, to signify lack of support to the compositor.
> +
> + Values set with this request are double-buffered. They will get applied
> + on the next zwp_text_input_v3.commit request, and stay valid until the
> + next enable or disable request.
> +
> + The initial values describing a cursor rectangle are empty. That means
> + the text input does not support describing the cursor area. If the
> + empty values get applied, subsequent attempts to change them may have
> + no effect.
> + </description>
> + <arg name="x" type="int"/>
> + <arg name="y" type="int"/>
> + <arg name="width" type="int"/>
> + <arg name="height" type="int"/>
> + </request>
> +
> + <request name="commit">
> + <description summary="commit state">
> + Text input state (content purpose, content hint, surrounding text,
> + cursor rectangle) is conceptually double-buffered within the context
> + of a text input, i.e. between an enable request and the following
> + enable or disable request.
> +
> + Protocol requests modify the pending state, as opposed to the current
> + state in use by the input method. A commit request atomically applies
> + all pending state, replacing the current state. After commit, the new
> + pending state is as documented for each related request.
> +
> + The enable request performs a special role by indicating that the state
Maybe "plays a special role" sounds more natural than "performs a special
role"?
> + should be reset and updated with new values on the nearest commit.
> +
> + The current or pending state are not modified unless noted otherwise.
> + </description>
> + </request>
> +
> + <event name="enter">
> + <description summary="enter event">
> + Notification that this seat's text-input focus is on a certain surface.
> +
> + When the seat has the keyboard capability the text-input focus follows
> + the keyboard focus.
> + </description>
> + <arg name="surface" type="object" interface="wl_surface"/>
> + </event>
> +
> + <event name="leave">
> + <description summary="leave event">
> + Notification that this seat's text-input focus is no longer on
> + a certain surface. The client should reset any preedit string previously
> + set.
> +
> + The leave notification is sent before the enter notification
> + for the new focus.
> +
> + When the seat has the keyboard capability the text-input focus follows
> + the keyboard focus.
> + </description>
> + <arg name="surface" type="object" interface="wl_surface"/>
> + </event>
> +
> + <event name="preedit_string">
> + <description summary="pre-edit">
> + Notify when a new composing text (pre-edit) should be set around the
> + current cursor position. Any previously set composing text should
> + be removed.
> +
> + Values set with this event are double-buffered. They must be applied on
> + the next zwp_text_input_v3.done event, and stay valid until the
> + next enable or disable request.
> +
> + The parameters cursor_begin and cursor_end are counted in Unicode
> + code points relative to the beginning of the submitted string. Cursor
> + should be hidden when both are equal to -1.
> +
> + They could be represented by the cient as a line if both values are the
> + same, or as a text highligt otherwise.
s/highligt/highlight/
> +
> + The initial value of text is an empty string, and cursor_begin and
> + cursor_end are both 0.
> + </description>
> + <arg name="text" type="string" allow-null="true"/>
> + <arg name="cursor_begin" type="int"/>
> + <arg name="cursor_end" type="int"/>
> + </event>
> +
> + <event name="commit_string">
> + <description summary="text commit">
> + Notify when text should be inserted into the editor widget. The text to
> + commit could be either just a single character after a key press or the
> + result of some composing (pre-edit).
> +
> + Values set with this event are double-buffered. They must be applied
> + and reset to initial on the next zwp_text_input_v3.done event.
> +
> + The initial value of text is an empty string.
> + </description>
> + <arg name="text" type="string" allow-null="true"/>
> + </event>
> +
> + <event name="delete_surrounding_text">
> + <description summary="delete surrounding text">
> + Notify when the text around the current cursor position should be
> + deleted. Before_length and after_length are the number of Unicode
> + code points before and after the current cursor position (excluding the
> + selection) to delete.
> +
> + Values set with this event are double-buffered. They must be applied
> + and reset to initial on the next zwp_text_input_v3.done event.
> +
> + The initial values of both before_length and after_length are 0.
> + </description>
> + <arg name="before_length" type="uint" summary="length of text before current cursor position"/>
> + <arg name="after_length" type="uint" summary="length of text after current cursor position"/>
> + </event>
> +
> + <event name="done">
> + <description summary="apply changes">
> + Instruct the application to apply changes to state requested by the
> + preedit_string, commit_string and delete_surrounding_string events. The
s/delete_surrounding_string/delete_surrounding_text/
Thanks for all the work!
Cheers,
Silvan
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