Work around startup UI freeze caused by QtTextToSpeech

This merge request works around an annoying startup hang that I introduced when adding text-to-speech to NeoChat. The previous implementation was a QML singleton that used the `TextToSpeech` QML component. Unfortunately that component blocks the UI thread when first loading it, while it connects to speech-dispatcher.

This MR just rewrites that singleton in C++, and moves initialization of QtTextToSpeech to the first time you read a message aloud. It doesn't fix the performance problem, but it at least stops it from affecting startup.

In the future, I'd like to move speech operations to a background thread to completely mitigate the initialization freeze.

CMakeLists.txt

@@ -56,7 +56,7 @@ ecm_setup_version(${PROJECT_VERSION}
     VERSION_HEADER ${CMAKE_CURRENT_BINARY_DIR}/neochat-version.h
 )
 
-find_package(Qt6 ${QT_MIN_VERSION} NO_MODULE COMPONENTS Core Quick Gui QuickControls2 Multimedia Svg WebView)
+find_package(Qt6 ${QT_MIN_VERSION} NO_MODULE COMPONENTS Core Quick Gui QuickControls2 Multimedia Svg TextToSpeech WebView)
 set_package_properties(Qt6 PROPERTIES
     TYPE REQUIRED
     PURPOSE "Basic application components"

src/app/CMakeLists.txt

@@ -37,10 +37,8 @@ add_library(neochat STATIC
     identityserverhelper.h
     models/commonroomsmodel.cpp
     models/commonroomsmodel.h
-)
-
-set_source_files_properties(qml/TextToSpeechWrapper.qml PROPERTIES
-    QT_QML_SINGLETON_TYPE TRUE
+    texttospeechhelper.h
+    texttospeechhelper.cpp
 )
 
 set_source_files_properties(qml/OsmLocationPlugin.qml PROPERTIES
@@ -87,7 +85,6 @@ ecm_add_qml_module(neochat URI org.kde.neochat GENERATE_PLUGIN_SOURCE
         qml/InvitationView.qml
         qml/AvatarTabButton.qml
         qml/OsmLocationPlugin.qml
-        qml/TextToSpeechWrapper.qml
         qml/FullScreenMap.qml
         qml/LocationsPage.qml
         qml/LocationMapItem.qml
@@ -204,6 +201,7 @@ target_link_libraries(neochat PUBLIC
     Qt::Multimedia
     Qt::Network
     Qt::QuickControls2
+    Qt::TextToSpeech
     KF6::I18n
     KF6::Kirigami
     KF6::Notifications

src/app/qml/Main.qml

@@ -196,7 +196,6 @@ Kirigami.ApplicationWindow {
         NeoChatSettingsView.window = root;
         NeoChatSettingsView.connection = root.connection;
         WindowController.setBlur(pageStack, NeoChatConfig.blur && !NeoChatConfig.compactLayout);
-        TextToSpeechWrapper.warmUp();
         if (ShareHandler.text && root.connection) {
             root.handleShare()
         }

src/app/qml/TextToSpeechWrapper.qml

@@ -1,24 +0,0 @@
-// SPDX-FileCopyrightText: 2025 Ritchie Frodomar <alkalinethunder@gmail.com>
-// SPDX-License-Identifier: GPL-2.0-or-later
-
-pragma Singleton
-
-import QtQuick
-import QtTextToSpeech
-
-QtObject {
-    id: root
-
-    readonly property TextToSpeech tts: TextToSpeech {
-        id: tts
-    }
-
-    function warmUp() {
-        // TODO: This method is called on startup to avoid a UI freeze the first time you read a message aloud, but there's nothing for it to do.
-        // This would be a good place to check if TTS can actually be used.
-    }
-
-    function say(text: String) {
-        tts.say(text)
-    }
-}

src/app/texttospeechhelper.cpp

@@ -0,0 +1,15 @@
+// SPDX-FileCopyrightText: 2025 Ritchie Frodomar <ritchie@kde.org>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#include "texttospeechhelper.h"
+
+void TextToSpeechHelper::speak(const QString &textToSpeak)
+{
+    if (!m_speech) {
+        m_speech = new QTextToSpeech();
+    }
+
+    m_speech->say(textToSpeak);
+}
+
+#include "moc_texttospeechhelper.cpp"

src/app/texttospeechhelper.h

@@ -0,0 +1,21 @@
+// SPDX-FileCopyrightText: 2025 Ritchie Frodomar <ritchie@kde.org>
+// SPDX-License-Identifier: GPL-2.0-only OR GPL-3.0-only OR LicenseRef-KDE-Accepted-GPL
+
+#pragma once
+
+#include <QObject>
+#include <QQmlEngine>
+#include <QtTextToSpeech>
+
+class TextToSpeechHelper : public QObject
+{
+    Q_OBJECT
+    QML_ELEMENT
+    QML_SINGLETON
+
+public:
+    Q_INVOKABLE void speak(const QString &textToSpeak);
+
+private:
+    QTextToSpeech *m_speech = nullptr;
+};

src/timeline/MessageDelegateContextMenu.qml

@@ -94,7 +94,7 @@ DelegateContextMenu {
         text: i18nc("@action:inmenu", "Read Text Aloud")
         icon.name: "audio-speakers-symbolic"
         onTriggered: {
-            TextToSpeechWrapper.say(i18nc("@info text-to-speech %1 is author %2 is message text", "%1 said %2", root.author.displayName, root.plainText))
+            TextToSpeechHelper.speak(i18nc("@info text-to-speech %1 is author %2 is message text", "%1 said %2", root.author.displayName, root.plainText))
         }
     }
     Kirigami.Action {