Add a ThemeChange event.

- Pass it from QWindowSystemInterface via QWindow to the widgets.
- Add handler code from 4.8 / qapplication_win.cpp to qwidget.cpp.

Change-Id: Ic759563aa00cb93fe014c1bf41020446c1927dec
Reviewed-by: Morten Johan Sørvig <morten.sorvig@nokia.com>
Reviewed-by: Samuel Rødal <samuel.rodal@nokia.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/src/widgets/kernel/qwidget.cpp b/src/widgets/kernel/qwidget.cpp
index f5a1ea15cd..f98f7fbe66 100644
--- a/src/widgets/kernel/qwidget.cpp
+++ b/src/widgets/kernel/qwidget.cpp
@@ -8046,6 +8046,7 @@ bool QWidget::event(QEvent *event)
     case QEvent::LocaleChange:
     case QEvent::MacSizeChange:
     case QEvent::ContentsRectChange:
+    case QEvent::ThemeChange:
         changeEvent(event);
         break;
 
@@ -8249,6 +8250,20 @@ void QWidget::changeEvent(QEvent * event)
         update();
         break;
 
+    case QEvent::ThemeChange:
+        if (QApplication::desktopSettingsAware() && windowType() != Qt::Desktop
+            && qApp && !QApplication::closingDown()) {
+            if (testAttribute(Qt::WA_WState_Polished))
+                QApplication::style()->unpolish(this);
+            if (testAttribute(Qt::WA_WState_Polished))
+                QApplication::style()->polish(this);
+            QEvent styleChangedEvent(QEvent::StyleChange);
+            QCoreApplication::sendEvent(this, &styleChangedEvent);
+            if (isVisible())
+                update();
+        }
+        break;
+
 #ifdef Q_WS_MAC
     case QEvent::MacSizeChange:
         updateGeometry();
diff --git a/src/widgets/kernel/qwidgetwindow_qpa.cpp b/src/widgets/kernel/qwidgetwindow_qpa.cpp
index c2524567f1..c04d8a9dc3 100644
--- a/src/widgets/kernel/qwidgetwindow_qpa.cpp
+++ b/src/widgets/kernel/qwidgetwindow_qpa.cpp
@@ -150,6 +150,12 @@ bool QWidgetWindow::event(QEvent *event)
         handleWindowStateChangedEvent(static_cast<QWindowStateChangeEvent *>(event));
         return true;
 
+    case QEvent::ThemeChange: {
+        QEvent widgetEvent(QEvent::ThemeChange);
+        QGuiApplication::sendSpontaneousEvent(m_widget, &widgetEvent);
+    }
+        return true;
+
     default:
         break;
     }