SDL: wayland: Add support for text-input-unstable-v3

From 74162b7401844d58ee82541b39c51ec2aa264867 Mon Sep 17 00:00:00 2001
From: Ethan Lee <[EMAIL REDACTED]>
Date: Thu, 29 Jul 2021 13:27:31 -0400
Subject: [PATCH] wayland: Add support for text-input-unstable-v3

---
 src/video/wayland/SDL_waylandevents.c        | 141 +++++-
 src/video/wayland/SDL_waylandevents_c.h      |   3 +
 src/video/wayland/SDL_waylandkeyboard.c      |  86 +++-
 src/video/wayland/SDL_waylandkeyboard.h      |   7 +
 src/video/wayland/SDL_waylandvideo.c         |  11 +-
 src/video/wayland/SDL_waylandvideo.h         |   1 +
 wayland-protocols/text-input-unstable-v3.xml | 452 +++++++++++++++++++
 7 files changed, 690 insertions(+), 11 deletions(-)
 create mode 100644 wayland-protocols/text-input-unstable-v3.xml

diff --git a/src/video/wayland/SDL_waylandevents.c b/src/video/wayland/SDL_waylandevents.c
index 29786d3879..a8e7c80ede 100644
--- a/src/video/wayland/SDL_waylandevents.c
+++ b/src/video/wayland/SDL_waylandevents.c
@@ -41,6 +41,7 @@
 #include "relative-pointer-unstable-v1-client-protocol.h"
 #include "xdg-shell-client-protocol.h"
 #include "keyboard-shortcuts-inhibit-unstable-v1-client-protocol.h"
+#include "text-input-unstable-v3-client-protocol.h"
 
 #ifdef HAVE_LIBDECOR_H
 #include <libdecor.h>
@@ -221,7 +222,7 @@ Wayland_PumpEvents(_THIS)
     WAYLAND_wl_display_flush(d->display);
 
 #ifdef SDL_USE_IME
-    if (SDL_GetEventState(SDL_TEXTINPUT) == SDL_ENABLE) {
+    if (d->text_input_manager == NULL && SDL_GetEventState(SDL_TEXTINPUT) == SDL_ENABLE) {
         SDL_IME_PumpEvents();
     }
 #endif
@@ -741,7 +742,9 @@ keyboard_handle_enter(void *data, struct wl_keyboard *keyboard,
         SDL_SetKeyboardFocus(window->sdlwindow);
     }
 #ifdef SDL_USE_IME
-    SDL_IME_SetFocus(SDL_TRUE);
+    if (!input->text_input) {
+        SDL_IME_SetFocus(SDL_TRUE);
+    }
 #endif
 }
 
@@ -760,8 +763,11 @@ keyboard_handle_leave(void *data, struct wl_keyboard *keyboard,
 
     /* This will release any keys still pressed */
     SDL_SetKeyboardFocus(NULL);
+
 #ifdef SDL_USE_IME
-    SDL_IME_SetFocus(SDL_FALSE);
+    if (!input->text_input) {
+        SDL_IME_SetFocus(SDL_FALSE);
+    }
 #endif
 }
 
@@ -1224,6 +1230,93 @@ static const struct wl_data_device_listener data_device_listener = {
     data_device_handle_selection
 };
 
+static void
+text_input_enter(void *data,
+                 struct zwp_text_input_v3 *zwp_text_input_v3,
+                 struct wl_surface *surface)
+{
+    /* No-op */
+}
+
+static void
+text_input_leave(void *data,
+                 struct zwp_text_input_v3 *zwp_text_input_v3,
+                 struct wl_surface *surface)
+{
+    /* No-op */
+}
+
+static void
+text_input_preedit_string(void *data,
+                          struct zwp_text_input_v3 *zwp_text_input_v3,
+                          const char *text,
+                          int32_t cursor_begin,
+                          int32_t cursor_end)
+{
+    char buf[SDL_TEXTEDITINGEVENT_TEXT_SIZE];
+    if (text) {
+        size_t text_bytes = SDL_strlen(text), i = 0;
+        size_t cursor = 0;
+
+        do {
+            const size_t sz = SDL_utf8strlcpy(buf, text+i, sizeof(buf));
+            const size_t chars = SDL_utf8strlen(buf);
+
+            SDL_SendEditingText(buf, cursor, chars);
+
+            i += sz;
+            cursor += chars;
+        } while (i < text_bytes);
+    } else {
+        buf[0] = '\0';
+        SDL_SendEditingText(buf, 0, 0);
+    }
+}
+
+static void
+text_input_commit_string(void *data,
+                         struct zwp_text_input_v3 *zwp_text_input_v3,
+                         const char *text)
+{
+    if (text && *text) {
+        char buf[SDL_TEXTINPUTEVENT_TEXT_SIZE];
+        size_t text_bytes = SDL_strlen(text), i = 0;
+
+        while (i < text_bytes) {
+            size_t sz = SDL_utf8strlcpy(buf, text+i, sizeof(buf));
+            SDL_SendKeyboardText(buf);
+
+            i += sz;
+        }
+    }
+}
+
+static void
+text_input_delete_surrounding_text(void *data,
+                                   struct zwp_text_input_v3 *zwp_text_input_v3,
+                                   uint32_t before_length,
+                                   uint32_t after_length)
+{
+    /* FIXME: Do we care about this event? */
+}
+
+static void
+text_input_done(void *data,
+                struct zwp_text_input_v3 *zwp_text_input_v3,
+                uint32_t serial)
+{
+    /* No-op */
+}
+
+static const struct zwp_text_input_v3_listener text_input_listener = {
+    text_input_enter,
+    text_input_leave,
+    text_input_preedit_string,
+    text_input_commit_string,
+    text_input_delete_surrounding_text,
+    text_input_done
+};
+
 static void
 Wayland_create_data_device(SDL_VideoData *d)
 {
@@ -1249,6 +1342,30 @@ Wayland_create_data_device(SDL_VideoData *d)
     }
 }
 
+static void
+Wayland_create_text_input(SDL_VideoData *d)
+{
+    SDL_WaylandTextInput *text_input = NULL;
+
+    text_input = SDL_calloc(1, sizeof *text_input);
+    if (text_input == NULL) {
+        return;
+    }
+
+    text_input->text_input = zwp_text_input_manager_v3_get_text_input(
+        d->text_input_manager, d->input->seat
+    );
+
+    if (text_input->text_input == NULL) {
+        SDL_free(text_input);
+    } else {
+        zwp_text_input_v3_set_user_data(text_input->text_input, text_input);
+        zwp_text_input_v3_add_listener(text_input->text_input,
+                                       &text_input_listener, text_input);
+        d->input->text_input = text_input;
+    }
+}
+
 void
 Wayland_add_data_device_manager(SDL_VideoData *d, uint32_t id, uint32_t version)
 {
@@ -1259,6 +1376,16 @@ Wayland_add_data_device_manager(SDL_VideoData *d, uint32_t id, uint32_t version)
     }
 }
 
+void
+Wayland_add_text_input_manager(SDL_VideoData *d, uint32_t id, uint32_t version)
+{
+    d->text_input_manager = wl_registry_bind(d->registry, id, &zwp_text_input_manager_v3_interface, 1);
+
+    if (d->input != NULL) {
+        Wayland_create_text_input(d);
+    }
+}
+
 void
 Wayland_display_add_input(SDL_VideoData *d, uint32_t id, uint32_t version)
 {
@@ -1277,6 +1404,9 @@ Wayland_display_add_input(SDL_VideoData *d, uint32_t id, uint32_t version)
     if (d->data_device_manager != NULL) {
         Wayland_create_data_device(d);
     }
+    if (d->text_input_manager != NULL) {
+        Wayland_create_text_input(d);
+    }
 
     wl_seat_add_listener(input->seat, &seat_listener, input);
     wl_seat_set_user_data(input->seat, input);
@@ -1305,6 +1435,11 @@ void Wayland_display_destroy_input(SDL_VideoData *d)
         SDL_free(input->data_device);
     }
 
+    if (input->text_input != NULL) {
+        zwp_text_input_v3_destroy(input->text_input->text_input);
+        SDL_free(input->text_input);
+    }
+
     if (input->keyboard)
         wl_keyboard_destroy(input->keyboard);
 
diff --git a/src/video/wayland/SDL_waylandevents_c.h b/src/video/wayland/SDL_waylandevents_c.h
index f3604ac360..e4b76d830e 100644
--- a/src/video/wayland/SDL_waylandevents_c.h
+++ b/src/video/wayland/SDL_waylandevents_c.h
@@ -27,6 +27,7 @@
 #include "SDL_waylandvideo.h"
 #include "SDL_waylandwindow.h"
 #include "SDL_waylanddatamanager.h"
+#include "SDL_waylandkeyboard.h"
 
 typedef struct {
     // repeat_rate in range of [1, 1000]
@@ -47,6 +48,7 @@ struct SDL_WaylandInput {
     struct wl_touch *touch;
     struct wl_keyboard *keyboard;
     SDL_WaylandDataDevice *data_device;
+    SDL_WaylandTextInput *text_input;
     struct zwp_relative_pointer_v1 *relative_pointer;
     struct zwp_confined_pointer_v1 *confined_pointer;
     SDL_Window *confined_pointer_window;
@@ -83,6 +85,7 @@ struct SDL_WaylandInput {
 extern void Wayland_PumpEvents(_THIS);
 
 extern void Wayland_add_data_device_manager(SDL_VideoData *d, uint32_t id, uint32_t version);
+extern void Wayland_add_text_input_manager(SDL_VideoData *d, uint32_t id, uint32_t version);
 
 extern void Wayland_display_add_input(SDL_VideoData *d, uint32_t id, uint32_t version);
 extern void Wayland_display_destroy_input(SDL_VideoData *d);
diff --git a/src/video/wayland/SDL_waylandkeyboard.c b/src/video/wayland/SDL_waylandkeyboard.c
index 88384b3512..747a886dda 100644
--- a/src/video/wayland/SDL_waylandkeyboard.c
+++ b/src/video/wayland/SDL_waylandkeyboard.c
@@ -24,12 +24,17 @@
 
 #include "../SDL_sysvideo.h"
 #include "SDL_waylandvideo.h"
+#include "SDL_waylandevents_c.h"
+#include "text-input-unstable-v3-client-protocol.h"
 
 int
 Wayland_InitKeyboard(_THIS)
 {
 #ifdef SDL_USE_IME
-    SDL_IME_Init();
+    SDL_VideoData *driverdata = _this->driverdata;
+    if (driverdata->text_input_manager == NULL) {
+        SDL_IME_Init();
+    }
 #endif
 
     return 0;
@@ -39,37 +44,106 @@ void
 Wayland_QuitKeyboard(_THIS)
 {
 #ifdef SDL_USE_IME
-    SDL_IME_Quit();
+    SDL_VideoData *driverdata = _this->driverdata;
+    if (driverdata->text_input_manager == NULL) {
+        SDL_IME_Quit();
+    }
 #endif
 }
 
 void
 Wayland_StartTextInput(_THIS)
 {
-    /* No-op */
+    SDL_VideoData *driverdata = _this->driverdata;
+
+    if (driverdata->text_input_manager) {
+        struct SDL_WaylandInput *input = driverdata->input;
+        if (input != NULL && input->text_input) {
+            const SDL_Rect *rect = &input->text_input->cursor_rect;
+
+            /* For some reason this has to be done twice, it appears to be a
+             * bug in mutter? Maybe?
+             * -flibit
+             */
+            zwp_text_input_v3_enable(input->text_input->text_input);
+            zwp_text_input_v3_commit(input->text_input->text_input);
+            zwp_text_input_v3_enable(input->text_input->text_input);
+            zwp_text_input_v3_commit(input->text_input->text_input);
+
+            /* Now that it's enabled, set the input properties */
+            zwp_text_input_v3_set_content_type(input->text_input->text_input,
+                                               ZWP_TEXT_INPUT_V3_CONTENT_HINT_NONE,
+                                               ZWP_TEXT_INPUT_V3_CONTENT_PURPOSE_NORMAL);
+            if (!SDL_RectEmpty(rect)) {
+                /* This gets reset on enable so we have to cache it */
+                zwp_text_input_v3_set_cursor_rectangle(input->text_input->text_input,
+                                                       rect->x,
+                                                       rect->y,
+                                                       rect->w,
+                                                       rect->h);
+            }
+            zwp_text_input_v3_commit(input->text_input->text_input);
+        }
+    }
 }
 
 void
 Wayland_StopTextInput(_THIS)
 {
+    SDL_VideoData *driverdata = _this->driverdata;
+
+    if (driverdata->text_input_manager) {
+        struct SDL_WaylandInput *input = driverdata->input;
+        if (input != NULL && input->text_input) {
+            zwp_text_input_v3_disable(input->text_input->text_input);
+            zwp_text_input_v3_commit(input->text_input->text_input);
+        }
+    }
+
 #ifdef SDL_USE_IME
-    SDL_IME_Reset();
+    else {
+        SDL_IME_Reset();
+    }
 #endif
 }
 
 void
 Wayland_SetTextInputRect(_THIS, SDL_Rect *rect)
 {
+    SDL_VideoData *driverdata = _this->driverdata;
+
     if (!rect) {
         SDL_InvalidParamError("rect");
         return;
     }
-       
+
+    if (driverdata->text_input_manager) {
+        struct SDL_WaylandInput *input = driverdata->input;
+        if (input != NULL && input->text_input) {
+            SDL_memcpy(&input->text_input->cursor_rect, rect, sizeof(SDL_Rect));
+            zwp_text_input_v3_set_cursor_rectangle(input->text_input->text_input,
+                                                   rect->x,
+                                                   rect->y,
+                                                   rect->w,
+                                                   rect->h);
+            zwp_text_input_v3_commit(input->text_input->text_input);
+        }
+    }
+
 #ifdef SDL_USE_IME
-    SDL_IME_UpdateTextRect(rect);
+    else {
+        SDL_IME_UpdateTextRect(rect);
+    }
 #endif
 }
 
+SDL_bool
+Wayland_HasScreenKeyboardSupport(_THIS)
+{
+    SDL_VideoData *driverdata = _this->driverdata;
+    return (driverdata->text_input_manager != NULL);
+}
+
 #endif /* SDL_VIDEO_DRIVER_WAYLAND */
 
 /* vi: set ts=4 sw=4 expandtab: */
diff --git a/src/video/wayland/SDL_waylandkeyboard.h b/src/video/wayland/SDL_waylandkeyboard.h
index cca8ac8d9b..efc53d0fc6 100644
--- a/src/video/wayland/SDL_waylandkeyboard.h
+++ b/src/video/wayland/SDL_waylandkeyboard.h
@@ -23,11 +23,18 @@
 #ifndef SDL_waylandkeyboard_h_
 #define SDL_waylandkeyboard_h_
 
+typedef struct SDL_WaylandTextInput
+{
+    struct zwp_text_input_v3 *text_input;
+    SDL_Rect cursor_rect;
+} SDL_WaylandTextInput;
+
 extern int Wayland_InitKeyboard(_THIS);
 extern void Wayland_QuitKeyboard(_THIS);
 extern void Wayland_StartTextInput(_THIS);
 extern void Wayland_StopTextInput(_THIS);
 extern void Wayland_SetTextInputRect(_THIS, SDL_Rect *rect);
+extern SDL_bool Wayland_HasScreenKeyboardSupport(_THIS);
 
 #endif /* SDL_waylandkeyboard_h_ */
 
diff --git a/src/video/wayland/SDL_waylandvideo.c b/src/video/wayland/SDL_waylandvideo.c
index 0a5cf6e089..478fe0b699 100644
--- a/src/video/wayland/SDL_waylandvideo.c
+++ b/src/video/wayland/SDL_waylandvideo.c
@@ -51,6 +51,7 @@
 #include "keyboard-shortcuts-inhibit-unstable-v1-client-protocol.h"
 #include "idle-inhibit-unstable-v1-client-protocol.h"
 #include "xdg-activation-v1-client-protocol.h"
+#include "text-input-unstable-v3-client-protocol.h"
 
 #ifdef HAVE_LIBDECOR_H
 #include <libdecor.h>
@@ -253,6 +254,7 @@ Wayland_CreateDevice(int devindex)
     device->DestroyWindow = Wayland_DestroyWindow;
     device->SetWindowHitTest = Wayland_SetWindowHitTest;
     device->FlashWindow = Wayland_FlashWindow;
+    device->HasScreenKeyboardSupport = Wayland_HasScreenKeyboardSupport;
 
     device->SetClipboardText = Wayland_SetClipboardText;
     device->GetClipboardText = Wayland_GetClipboardText;
@@ -507,6 +509,8 @@ display_handle_global(void *data, struct wl_registry *registry, uint32_t id,
         d->idle_inhibit_manager = wl_registry_bind(d->registry, id, &zwp_idle_inhibit_manager_v1_interface, 1);
     } else if (SDL_strcmp(interface, "xdg_activation_v1") == 0) {
         d->activation_manager = wl_registry_bind(d->registry, id, &xdg_activation_v1_interface, 1);
+    } else if (strcmp(interface, "zwp_text_input_manager_v3") == 0) {
+        Wayland_add_text_input_manager(d, id, version);
     } else if (SDL_strcmp(interface, "wl_data_device_manager") == 0) {
         Wayland_add_data_device_manager(d, id, version);
     } else if (SDL_strcmp(interface, "zxdg_decoration_manager_v1") == 0) {
@@ -642,6 +646,11 @@ Wayland_VideoQuit(_THIS)
     if (data->key_inhibitor_manager)
         zwp_keyboard_shortcuts_inhibit_manager_v1_destroy(data->key_inhibitor_manager);
 
+    Wayland_QuitKeyboard(_this);
+
+    if (data->text_input_manager)
+        zwp_text_input_manager_v3_destroy(data->text_input_manager);
+
     if (data->xkb_context) {
         WAYLAND_xkb_context_unref(data->xkb_context);
         data->xkb_context = NULL;
@@ -684,8 +693,6 @@ Wayland_VideoQuit(_THIS)
     if (data->registry)
         wl_registry_destroy(data->registry);
 
-    Wayland_QuitKeyboard(_this);
-
     SDL_free(data->classname);
 }
 
diff --git a/src/video/wayland/SDL_waylandvideo.h b/src/video/wayland/SDL_waylandvideo.h
index f44706f1c4..ef769cee34 100644
--- a/src/video/wayland/SDL_waylandvideo.h
+++ b/src/video/wayland/SDL_waylandvideo.h
@@ -62,6 +62,7 @@ typedef struct {
     struct zwp_keyboard_shortcuts_inhibit_manager_v1 *key_inhibitor_manager;
     struct zwp_idle_inhibit_manager_v1 *idle_inhibit_manager;
     struct xdg_activation_v1 *activation_manager;
+    struct zwp_text_input_manager_v3 *text_input_manager;
 
     EGLDisplay edpy;
     EGLContext context;
diff --git a/wayland-protocols/text-input-unstable-v3.xml b/wayland-protocols/text-input-unstable-v3.xml
new file mode 100644
index 0000000000..d5f6322b0a
--- /dev/null
+++ b/wayland-protocols/text-input-unstable-v3.xml
@@ -0,0 +1,452 @@
+<?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>
+
+  <description summary="Protocol for composing text">
+    This protocol allows compositors to act as input methods and to send text
+    to applications. A text input object is used to manage state of what are
+    typically text entry fields in the application.
+
+    This document adheres to the RFC 2119 when using words like "must",
+    "should", "may", etc.
+
+    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>
+
+  <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 preedit_string and commit_string events.
+
+      Text is valid UTF-8 encoded, indices and lengths are in bytes. Indices
+      must not point to middle bytes inside a code point: they must either
+      point to the first byte of a code point or to the end of the buffer.
+      Lengths must be measured between two valid indices.
+
+      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 commit 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.
+    </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 on the surface previously obtained from the enter
+        event.
+
+        This request must be issued every time the active text input changes
+        to a new one, including within the current surface. Use
+        zwp_text_input_v3.disable when there is no longer any input focus on
+        the current surface.
+
+        Clients must not enable more than one text input on the single seat
+        and should disable the current text input before enabling the new one.
+        At most one instance of text input may be in enabled state per instance,
+        Requests to enable the another text input when some text input is active
+        must be ignored by compositor.
+
+        This request resets all state associated with previous enable, disable,
+        set_surrounding_text, set_text_change_cause, 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 must follow if the text input supports the necessary
+        functionality.
+
+        State set with this request is double-buffered. It will get applied on
+        the next zwp_text_input_v3.commit request, and stay valid until the
+        next committed enable or disable request.
+
+        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 on the current surface (typically when
+        there is no focus on any text entry inside the surface).
+
+        State set with this request is double-buffered. It will get applied on
+        the next zwp_text_input_v3.commit request.
+      </description>
+    </request>
+
+    <request name="set_surrounding_text">
+      <description summary="sets the surrounding text">
+        Sets the surrounding plain text around the input, excluding the preedit
+        text.
+
+        The client should notify the compositor of any changes in any of the
+        values carried with this request, including changes caused by handling
+        incoming text-input events as well as changes caused by other
+        mechanisms like keyboard typing.
+
+        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.
+
+        Text is UTF-8 encoded, and should include the cursor position, the
+        complete selection and additional characters before and after them.
+        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 text buffer.
+
+        Anchor is the byte offset of the selection anchor within text buffer.
+        If there is no selected text, anchor is the same as cursor.
+
+        If any preedit text is present, it is replaced with a cursor for the
+        purpose of this event.
+
+        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 committed 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="change_cause">
+      <description summary="text change reason">
+        Reason for the change of surrounding text or cursor posision.
+      </description>
+      <entry name="input_method" value="0" summary="input method caused the change"/>
+      <entry name="other" value="1" summary="something else than the input method caused the change"/>
+    </enum>
+
+    <request name="set_text_change_cause">
+      <description summary="indicates the cause of surrounding text change">
+        Tells the compositor why the text surrounding the cursor changed.
+
+        Whenever the client detects an external change in text, cursor, or
+        anchor posision, 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 request is double-buffered. It must be applied
+        and reset to initial at the next zwp_text_input_v3.commit request.
+
+        The initial value of cause is input_method.
+      </description>
+      <arg name="cause" type="uint" enum="change_cause"/>
+    </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 next zwp_text_input_v3.commit request.
+        Subsequent attempts to update them may have no effect. The values
+        remain valid until the next committed 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 committed 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">
+        Atomically applies state changes recently sent to the compositor.
+
+        The commit request establishes and updates the state of the client, and
+        must be issued after any changes to apply them.
+
+        Text input state (enabled status, content purpose, content hint,
+        surrounding text and change cause, cursor rectangle) is conceptually
+        double-buffered within the context of a text input, i.e. between a
+        committed enable request and the following committed 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.
+
+        Requests are applied in the order of arrival.
+
+        Neither current nor pending state are modified unless noted otherwise.
+
+        The compositor must count the number of commit requests coming from
+        each zwp_text_input_v3 object and use the count as the serial in done
+        events.
+      </description>
+    </request>
+
+    <event name="enter">
+      <description summary="enter event">
+        Notification that this seat's text-input focus is on a certain surface.

(Patch may be truncated, please check the link at the top of this post.)