core/window: add closed() signal to all window types

src/window/proxywindow.cpp

@@ -188,7 +188,7 @@ void ProxyWindowBase::connectWindow() {
 	this->window->setProxy(this);
 
 	// clang-format off
-	QObject::connect(this->window, &QWindow::visibilityChanged, this, &ProxyWindowBase::visibleChanged);
+	QObject::connect(this->window, &QWindow::visibilityChanged, this, &ProxyWindowBase::onVisibleChanged);
 	QObject::connect(this->window, &QWindow::xChanged, this, &ProxyWindowBase::xChanged);
 	QObject::connect(this->window, &QWindow::yChanged, this, &ProxyWindowBase::yChanged);
 	QObject::connect(this->window, &QWindow::widthChanged, this, &ProxyWindowBase::widthChanged);
@@ -226,6 +226,16 @@ void ProxyWindowBase::completeWindow() {
 	emit this->screenChanged();
 }
 
+void ProxyWindowBase::onVisibleChanged() {
+	if (this->mVisible && !this->window->isVisible()) {
+		this->mVisible = false;
+		this->setVisibleDirect(false);
+		emit this->closed();
+	}
+
+	emit this->visibleChanged();
+}
+
 bool ProxyWindowBase::deleteOnInvisible() const { return false; }
 
 QQuickWindow* ProxyWindowBase::backingWindow() const { return this->window; }

src/window/proxywindow.hpp

@@ -141,6 +141,7 @@ public:
 	[[nodiscard]] QQmlListProperty<QObject> data();
 
 signals:
+	void closed();
 	void windowConnected();
 	void windowDestroyed();
 	void visibleChanged();
@@ -160,6 +161,7 @@ signals:
 	void polished();
 
 protected slots:
+	void onVisibleChanged();
 	virtual void onWidthChanged();
 	virtual void onHeightChanged();
 	void onMaskChanged();

src/window/windowinterface.cpp

@@ -133,6 +133,7 @@ QQmlListProperty<QObject> WindowInterface::data() const { return this->proxyWind
 void WindowInterface::connectSignals() const {
 	auto* window = this->proxyWindow();
 	// clang-format off
+	QObject::connect(window, &ProxyWindowBase::closed, this, &WindowInterface::closed);
 	QObject::connect(window, &ProxyWindowBase::windowConnected, this, &WindowInterface::windowConnected);
 	QObject::connect(window, &ProxyWindowBase::visibleChanged, this, &WindowInterface::visibleChanged);
 	QObject::connect(window, &ProxyWindowBase::backerVisibilityChanged, this, &WindowInterface::backingWindowVisibleChanged);

src/window/windowinterface.hpp

@@ -236,6 +236,9 @@ public:
 	static QsWindowAttached* qmlAttachedProperties(QObject* object);
 
 signals:
+	/// This signal is emitted when the window is closed by the user, the display server,
+	/// or an error. It is not emitted when @@visible is set to false.
+	void closed();
 	void windowConnected();
 	void visibleChanged();
 	void backingWindowVisibleChanged();