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

Carlos Garnacho carlosg at gnome.org
Sun Mar 11 19:30:14 UTC 2018

This new protocol description is a vast simplification over v2, highlights
- 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>


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.

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 :).



 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				\
+	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.
+  </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
+       input.
+      </description>
+      <entry name="none" value="0x0" summary="no special behaviour"/>
+      <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
+        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).
+      </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"/>
+      <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)"/>
+      <entry name="pin" value="9" summary="input is a numeric password (combine with password or 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.
+       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>
+    <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>

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