From 68a9c5fe513e147e4cffd29b50a4714813df411e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Tor=20Arne=20Vestb=C3=B8?= <tor.arne.vestbo@qt.io>
Date: Wed, 9 Apr 2025 10:54:49 +0200
Subject: [PATCH] Remove QWindow argument from
 QWindowSystemInterface::handleThemeChange

The QPlatformTheme, and consumers on top such as QStyleHints, are app
global, so it doesn't make sense to notify that a single window has
changed its theme.

None of the QPA plugins pass a QWindow to the function today, after
the Windows plugin was taught a few new tricks in a preceding change.

[ChangeLog][QPA] QWindowSystemInterface::handleThemeChange no longer
takes an optional QWindow.

Change-Id: Ia761c95559a56a00763bd3cb95332f377e8de483
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
---
 src/gui/kernel/qguiapplication.cpp        | 7 ++-----
 src/gui/kernel/qwindowsysteminterface.cpp | 4 ++--
 src/gui/kernel/qwindowsysteminterface.h   | 2 +-
 src/gui/kernel/qwindowsysteminterface_p.h | 5 ++---
 4 files changed, 7 insertions(+), 11 deletions(-)

diff --git a/src/gui/kernel/qguiapplication.cpp b/src/gui/kernel/qguiapplication.cpp
index c516c56bc78..3630537de26 100644
--- a/src/gui/kernel/qguiapplication.cpp
+++ b/src/gui/kernel/qguiapplication.cpp
@@ -2807,7 +2807,7 @@ void QGuiApplicationPrivate::processSafeAreaMarginsChangedEvent(QWindowSystemInt
     QGuiApplication::sendSpontaneousEvent(wse->window, &event);
 }
 
-void QGuiApplicationPrivate::processThemeChanged(QWindowSystemInterfacePrivate::ThemeChangeEvent *tce)
+void QGuiApplicationPrivate::processThemeChanged(QWindowSystemInterfacePrivate::ThemeChangeEvent *)
 {
     if (self)
         self->handleThemeChanged();
@@ -2815,10 +2815,7 @@ void QGuiApplicationPrivate::processThemeChanged(QWindowSystemInterfacePrivate::
     QIconPrivate::clearIconCache();
 
     QEvent themeChangeEvent(QEvent::ThemeChange);
-    if (tce->window)
-        QGuiApplication::sendSpontaneousEvent(tce->window, &themeChangeEvent);
-    else
-        QGuiApplication::sendSpontaneousEvent(qGuiApp, &themeChangeEvent);
+    QGuiApplication::sendSpontaneousEvent(qGuiApp, &themeChangeEvent);
 }
 
 void QGuiApplicationPrivate::handleThemeChanged()
diff --git a/src/gui/kernel/qwindowsysteminterface.cpp b/src/gui/kernel/qwindowsysteminterface.cpp
index 97201770d8b..fa3e2f1d04f 100644
--- a/src/gui/kernel/qwindowsysteminterface.cpp
+++ b/src/gui/kernel/qwindowsysteminterface.cpp
@@ -828,9 +828,9 @@ void QWindowSystemInterface::handleScreenRefreshRateChange(QScreen *screen, qrea
     handleWindowSystemEvent<QWindowSystemInterfacePrivate::ScreenRefreshRateEvent>(screen, newRefreshRate);
 }
 
-QT_DEFINE_QPA_EVENT_HANDLER(void, handleThemeChange, QWindow *window)
+QT_DEFINE_QPA_EVENT_HANDLER(void, handleThemeChange)
 {
-    handleWindowSystemEvent<QWindowSystemInterfacePrivate::ThemeChangeEvent, Delivery>(window);
+    handleWindowSystemEvent<QWindowSystemInterfacePrivate::ThemeChangeEvent, Delivery>();
 }
 
 #if QT_CONFIG(draganddrop)
diff --git a/src/gui/kernel/qwindowsysteminterface.h b/src/gui/kernel/qwindowsysteminterface.h
index b50afedf14c..d6783fca47f 100644
--- a/src/gui/kernel/qwindowsysteminterface.h
+++ b/src/gui/kernel/qwindowsysteminterface.h
@@ -199,7 +199,7 @@ public:
     static void handleScreenRefreshRateChange(QScreen *screen, qreal newRefreshRate);
 
     template<typename Delivery = QWindowSystemInterface::DefaultDelivery>
-    static void handleThemeChange(QWindow *window = nullptr);
+    static void handleThemeChange();
 
     static void handleFileOpenEvent(const QString& fileName);
     static void handleFileOpenEvent(const QUrl &url);
diff --git a/src/gui/kernel/qwindowsysteminterface_p.h b/src/gui/kernel/qwindowsysteminterface_p.h
index cfc1604795e..2d2637dfa4f 100644
--- a/src/gui/kernel/qwindowsysteminterface_p.h
+++ b/src/gui/kernel/qwindowsysteminterface_p.h
@@ -329,9 +329,8 @@ public:
 
     class ThemeChangeEvent : public WindowSystemEvent {
     public:
-        explicit ThemeChangeEvent(QWindow * w)
-            : WindowSystemEvent(ThemeChange), window(w) { }
-        QPointer<QWindow> window;
+        explicit ThemeChangeEvent()
+            : WindowSystemEvent(ThemeChange) { }
     };
 
     class ExposeEvent : public WindowSystemEvent {