feat(wayland): text input through zwp_text_input_v3

A window can now say that a text field has the focus and where its caret
is — Window::SetTextInput(active, caret rectangle in physical pixels,
purpose) — which is what opens the on-screen keyboard on a phone (Maliit
under KWin, squeekboard under phoc). What the input method produces comes
back as events: committed text as onTextInput, the composing text as
onPreedit (empty clears it), deletions around the cursor as
onTextInputDelete; done() applies them in the protocol's order. The state
a window wants is remembered and sent again whenever the keyboard focus
returns to it. The protocol's client code is generated with wayland-scanner
1.26.0 from wayland-protocols' text-input-unstable-v3.xml, under lib/ like
the others.

implementations/Crafter.Graphics-Device.cpp

@@ -15,6 +15,7 @@ module;
 #include "../lib/wayland-xdg-decoration-unstable-v1-client-protocol.h"
 #include "../lib/fractional-scale-v1.h"
 #include "../lib/viewporter.h"
+#include "../lib/text-input-unstable-v3-client-protocol.h"
 #include <wayland-client.h>
 #include <wayland-client-protocol.h>
 #include <stdio.h>
@@ -303,6 +304,10 @@ void Device::handle_global(void *data, wl_registry *registry, std::uint32_t name
 		if (dataDeviceManager != nullptr && dataDevice == nullptr) {
 			dataDevice = wl_data_device_manager_get_data_device(dataDeviceManager, seat);
 		}
+		if (textInputManager != nullptr && textInput == nullptr) {
+			textInput = zwp_text_input_manager_v3_get_text_input(textInputManager, seat);
+			zwp_text_input_v3_add_listener(textInput, &text_input_listener, nullptr);
+		}
 	} else if (compositor == nullptr && strcmp(interface, wl_compositor_interface.name) == 0) {
 		compositor = reinterpret_cast<wl_compositor*>(wl_registry_bind(registry, name, &wl_compositor_interface, 3));
 	} else if (strcmp(interface, xdg_wm_base_interface.name) == 0) {
@@ -324,9 +329,84 @@ void Device::handle_global(void *data, wl_registry *registry, std::uint32_t name
 		if (seat != nullptr && dataDevice == nullptr) {
 			dataDevice = wl_data_device_manager_get_data_device(dataDeviceManager, seat);
 		}
+	} else if (strcmp(interface, zwp_text_input_manager_v3_interface.name) == 0) {
+		textInputManager = reinterpret_cast<zwp_text_input_manager_v3*>(wl_registry_bind(registry, name, &zwp_text_input_manager_v3_interface, 1));
+		if (seat != nullptr && textInput == nullptr) {
+			textInput = zwp_text_input_manager_v3_get_text_input(textInputManager, seat);
+			zwp_text_input_v3_add_listener(textInput, &text_input_listener, nullptr);
+		}
 	}
 }
 
+void Device::text_input_enter(void*, zwp_text_input_v3*, wl_surface* surface) {
+    textInputWindow = nullptr;
+    for (Window* window : windows) {
+        if (window->surface == surface) textInputWindow = window;
+    }
+    if (textInputWindow != nullptr && textInputWindow->textInputActive_) ApplyTextInput(textInputWindow);
+}
+
+void Device::text_input_leave(void*, zwp_text_input_v3*, wl_surface*) {
+    textInputWindow = nullptr;
+    textInputHasPreedit = textInputHasCommit = textInputHasDelete = false;
+    textInputPreedit.clear();
+    textInputShownPreedit.clear();
+}
+
+void Device::text_input_preedit(void*, zwp_text_input_v3*, const char* text, std::int32_t, std::int32_t) {
+    textInputPreedit = text == nullptr ? "" : text;
+    textInputHasPreedit = true;
+}
+
+void Device::text_input_commit(void*, zwp_text_input_v3*, const char* text) {
+    textInputCommit = text == nullptr ? "" : text;
+    textInputHasCommit = true;
+}
+
+void Device::text_input_delete(void*, zwp_text_input_v3*, std::uint32_t before, std::uint32_t after) {
+    textInputDeleteBefore = before;
+    textInputDeleteAfter = after;
+    textInputHasDelete = true;
+}
+
+// The protocol's order: the deletion around the cursor, then the committed
+// text at the cursor, then the composing text after it. The pending values
+// reset with every done, so a round that set no preedit means an empty one;
+// the window hears about it only when that differs from what it shows.
+void Device::text_input_done(void*, zwp_text_input_v3*, std::uint32_t) {
+    Window* window = textInputWindow;
+    if (!textInputHasPreedit) textInputPreedit.clear();
+    if (window != nullptr) {
+        if (textInputHasDelete && (textInputDeleteBefore > 0 || textInputDeleteAfter > 0)) window->onTextInputDelete.Invoke({ textInputDeleteBefore, textInputDeleteAfter });
+        if (textInputHasCommit && !textInputCommit.empty()) window->onTextInput.Invoke(textInputCommit);
+        if (textInputPreedit != textInputShownPreedit || (textInputHasCommit && !textInputCommit.empty())) {
+            textInputShownPreedit = textInputPreedit;
+            window->onPreedit.Invoke(textInputPreedit);
+        }
+    }
+    textInputHasPreedit = textInputHasCommit = textInputHasDelete = false;
+    textInputCommit.clear();
+}
+
+void Device::ApplyTextInput(Window* window) {
+    if (textInput == nullptr || window == nullptr || textInputWindow != window) return;
+    if (window->textInputActive_) {
+        zwp_text_input_v3_enable(textInput);
+        const bool phone = window->textInputPurpose_ == TextInputPurpose::Phone;
+        zwp_text_input_v3_set_content_type(textInput,
+            phone ? ZWP_TEXT_INPUT_V3_CONTENT_HINT_NONE : (ZWP_TEXT_INPUT_V3_CONTENT_HINT_COMPLETION | ZWP_TEXT_INPUT_V3_CONTENT_HINT_SPELLCHECK | ZWP_TEXT_INPUT_V3_CONTENT_HINT_AUTO_CAPITALIZATION),
+            phone ? ZWP_TEXT_INPUT_V3_CONTENT_PURPOSE_PHONE : ZWP_TEXT_INPUT_V3_CONTENT_PURPOSE_NORMAL);
+        const float s = window->scale > 0.0f ? window->scale : 1.0f;
+        zwp_text_input_v3_set_cursor_rectangle(textInput,
+            static_cast<std::int32_t>(window->textInputRect_[0] / s), static_cast<std::int32_t>(window->textInputRect_[1] / s),
+            std::max(1, static_cast<std::int32_t>(window->textInputRect_[2] / s)), std::max(1, static_cast<std::int32_t>(window->textInputRect_[3] / s)));
+    } else {
+        zwp_text_input_v3_disable(textInput);
+    }
+    zwp_text_input_v3_commit(textInput);
+    wl_display_flush(display);
+}
+
 void Device::handle_global_remove(void* data, wl_registry* registry, uint32_t name) {
 	
 }

implementations/Crafter.Graphics-Window.cpp

@@ -11,6 +11,7 @@ module;
 #include "../lib/wayland-xdg-decoration-unstable-v1-client-protocol.h"
 #include "../lib/fractional-scale-v1.h"
 #include "../lib/viewporter.h"
+#include "../lib/text-input-unstable-v3-client-protocol.h"
 #include <string.h>
 #include <cassert>
 #include <linux/input.h>
@@ -561,6 +562,7 @@ Window::~Window() {
         Device::touchWindow = nullptr;
         Device::touchPositions.clear();
     }
+    if (Device::textInputWindow == this) Device::textInputWindow = nullptr;
     #endif
 }
 #endif
@@ -618,6 +620,18 @@ void Window::SetTitle(const std::string_view title) {
     #endif
 }
 
+void Window::SetTextInput(bool active, std::int32_t x, std::int32_t y, std::int32_t width, std::int32_t height, TextInputPurpose purpose) {
+    #ifdef CRAFTER_GRAPHICS_WINDOW_WAYLAND
+    textInputActive_ = active;
+    textInputRect_[0] = x;
+    textInputRect_[1] = y;
+    textInputRect_[2] = width;
+    textInputRect_[3] = height;
+    textInputPurpose_ = purpose;
+    Device::ApplyTextInput(this);
+    #endif
+}
+
 void Window::SetCursorImage(std::uint16_t width, std::uint16_t height,
                             std::uint16_t hotspotX, std::uint16_t hotspotY,
                             const std::uint8_t* pixels) {