[PATCH wayland-protocols] text-input: Add v3 of the text-input protocol

Silvan Jegen s.jegen at gmail.com
Sun Apr 1 15:39:21 UTC 2018


Hi

Please find some comments and questions below.

On Sun, Mar 11, 2018 at 08:30:14PM +0100, Carlos Garnacho wrote:
> This new protocol description is a vast simplification over v2, highlights
> are:
> - All pre-edit text styling is gone, the protocol doesn't seem the place
>   to convey UI state. Clients are in better knowledge of how to make the
>   pre-edit string distinguishable from regular text.
> - No input panel (OSK) state nor covered rectangle events. This leaks
>   assumptions about the coordinate space of windows, and clients aren't
>   fully capable of handling all possible situations (eg. if the OSK fully
>   covers the surface). At the very least it could be split into a generic
>   protocol of its own, this version of the protocol simply doesn't get
>   into this business, compositors are still free to handle situations where
>   the keyboard focus rectangle is covered by the input panel.
> - Less state is to be kept on compositors. Clients must now reissue all
>   applying IM state whenever the surface gains focus (or internal focus
>   changes), instead of state requests being independent from focus.
> - No set_preferred_language request for clients, modern desktops have
>   generally moved towards session-wide IM settings, it seems hard to
>   conciliate this piece of information flowing in both directions.
> - There is no event to send keysyms. The handling ought to be by all means
>   identical to wl_keyboard's, compositors might just use that interface.
> 
> Signed-off-by: Carlos Garnacho <carlosg at gnome.org>
> ---
> 
> Hey,
> 
> Belatedly, here's my proposed v3 of the text-input protocol, a rename of
> what is implemented on gnome-shell/gtk+. It basically is a
> (over?)simplification compared to v2, the main difference besides the
> punted functionality is the simplified messaging flow, state is considered
> reset after enter/leave, or on .disable requests from the client, all
> new state must be submitted afterwards.

Is v3 of the text-input protocol compatible with v1 of the input-method
protocol? I would assume so but I am wondering if that should be pointed
out somewhere.


> Some of the removed things are maybe debatable (eg. the keysym event,
> or language preference request/signal, although I don't see that working
> out of the box widely, highly toolkit specific at best). For stuff like
> the old input_panel_state request to do client-side UI magic to keep
> keyboard focus visible I'm personally more opinionated though :).
> 
> Comments?
>
> Cheers,
>   Carlos
> 
>  Makefile.am                                    |   2 +
>  unstable/text-input/text-input-unstable-v3.xml | 293 +++++++++++++++++++++++++
>  2 files changed, 295 insertions(+)
>  create mode 100644 unstable/text-input/text-input-unstable-v3.xml
> 
> diff --git a/Makefile.am b/Makefile.am
> index 4b9a901..31a36fe 100644
> --- a/Makefile.am
> +++ b/Makefile.am
> @@ -3,6 +3,8 @@ 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-v2.xml				\

v2 has never been commited to the repo so it probably has to be added
there at one point?


> +	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..f8369b0
> --- /dev/null
> +++ b/unstable/text-input/text-input-unstable-v3.xml
> @@ -0,0 +1,293 @@
> +<?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.
> +
> +    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 bytes. Indices
> +      have to always point to the first byte of an UTF-8 encoded code point.
> +      Lengths are not allowed to contain just a part of an UTF-8 encoded code
> +      point.
> +
> +      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>
> +
> +    <enum name="enable_flags" bitfield="true">
> +      <description summary="enable flags">
> +       Content hint is a bitmask to allow to modify the behavior of the text

This description is a C&P error and should be something like:

Enable flags is a bitmask that indicates the details of the capabilities
of the text input that is being requested.


> +       input.
> +      </description>
> +      <entry name="none" value="0x0" summary="no special behaviour"/>

The spelling of behaviour/behavior should be consistent. I assume American
spellings are preferred throughout the project so it should be "behavior"
everywhere.


> +      <entry name="can_show_preedit" value="0x1" summary="hints that the UI is capable of showing pre-edit text"/>
> +      <entry name="toggle_input_panel" value="0x2" summary="requests toggling input panel (eg. on-screen keyboard)"/>
> +    </enum>
> +
> +    <request name="enable">
> +      <description summary="Request text input to be enabled">
> +	Requests text input on a surface. The serial provided must be the one

Whitespace issue: tab as first character.


> +        received on zwp_text_input_v3.enter.
> +      </description>
> +      <arg name="serial" type="uint" summary="serial of enter event"/>
> +      <arg name="flags" type="uint" enum="enable_flags" summary="details of the enable request"/>
> +    </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).

Whitespace issue: tab as first character.


> +      </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 byte offset within the surrounding text.
> +       Anchor is the byte offset of the selection anchor within the
> +       surrounding text. If there is no selected text, anchor is the same as
> +       cursor.
> +
> +       Make sure to always send some text before and after the cursor
> +       except when the cursor is at the beginning or end of text.
> +
> +       There is a maximum length of wayland messages so text can not be
> +       longer than 4000 bytes.
> +      </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 behaviour"/>
> +      <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"/>

The "latin" in the summary should probably be capitalized.


> +      <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 password or sensitive_data hint)"/>

There is no "password" hint in the "content_hint" num so I think this
should say:

<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 password or sensitive_data hint)"/>

Ditto


> +      <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.
> +
> +       When no content type is explicitly set, a normal content purpose with
> +       none hint should be assumed.
> +      </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">
> +       Sets the cursor outline as a x, y, width, height rectangle in surface
> +       local coordinates.
> +
> +       Allows the compositor to put a window with word suggestions near the
> +       cursor.
> +      </description>
> +      <arg name="x" type="int"/>
> +      <arg name="y" type="int"/>
> +      <arg name="width" type="int"/>
> +      <arg name="height" type="int"/>
> +    </request>

If I understand correctly this request indicates where the compositor is
allowed to show the input method's word suggestion surface, correct?

Is this being used in Gnome-shell? I couldn't find it being mentioned in
the Github repo at https://github.com/GNOME/gnome-shell.


Cheers,

Silvan


> +    <request name="commit">
> +      <description summary="commit state">
> +       Allows to atomically send state updates from client. The previous
> +       set_surrounding_text, set_content_type and set_cursor_rectangle
> +       become effective after this call.
> +
> +       Serial should be set to the serial from the last wp_text_input.enter
> +       event.
> +      </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="serial" type="uint" summary="serial"/>
> +      <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="serial" type="uint"/>
> +      <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.
> +      </description>
> +      <arg name="text" type="string" allow-null="true"/>
> +      <arg name="cursor" type="uint"/>
> +    </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).
> +
> +       The text argument could be also null if some text is removed (see
> +       zwp_text_input_v3.delete_surrounding_text).
> +
> +       Any previously set composing text should be removed.
> +      </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 is the length (in bytes) of text
> +       before and after the current cursor position (excluding the selection)
> +       to delete.
> +
> +       This event should be handled as part of a following commit_string or
> +       preedit_string event.
> +      </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>
> +  </interface>
> +
> +  <interface name="zwp_text_input_manager_v3" version="1">
> +    <description summary="text input manager">
> +      A factory for text-input objects. This object is a global singleton.
> +    </description>
> +
> +    <request name="destroy" type="destructor">
> +      <description summary="Destroy the wp_text_input_manager">
> +       Destroy the wp_text_input_manager object.
> +      </description>
> +    </request>
> +
> +    <request name="get_text_input">
> +      <description summary="create a new text input object">
> +       Creates a new text-input object for a given seat.
> +      </description>
> +      <arg name="id" type="new_id" interface="zwp_text_input_v3"/>
> +      <arg name="seat" type="object" interface="wl_seat"/>
> +    </request>
> +  </interface>
> +</protocol>
> -- 
> 2.14.3
> 
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