Properly handle the expose event for QWindow.

src/gui/kernel/qwindow_qpa.cpp

@@ -327,6 +327,12 @@ QPlatformWindow *QWindow::handle() const
     return d->platformWindow;
 }
 
+QWindowSurface *QWindow::surface() const
+{
+    Q_D(const QWindow);
+    return d->surface;
+}
+
 void QWindow::showMinimized()
 {
     qDebug() << "unimplemented:" << __FILE__ << __LINE__;

src/gui/kernel/qwindow_qpa.h

@@ -66,6 +66,7 @@ class QWheelEvent;
 
 class QPlatformWindow;
 class QWindowContext;
+class QWindowSurface;
 
 class Q_GUI_EXPORT QWindow : public QObject
 {
@@ -132,6 +133,7 @@ public:
     void destroy();
 
     QPlatformWindow *handle() const;
+    QWindowSurface *surface() const;
 
 public Q_SLOTS:
     inline void show() { setVisible(true); }
@@ -174,6 +176,7 @@ private:
 
     friend class QGuiApplication;
     friend class QGuiApplicationPrivate;
+    friend class QWindowSurface;
 };
 
 QT_END_NAMESPACE

src/gui/kernel/qwindow_qpa_p.h

@@ -62,13 +62,13 @@ public:
         , platformWindow(0)
         , visible(false)
         , glContext(0)
+        , surface(0)
     {
         isWindow = true;
     }
 
     ~QWindowPrivate()
     {
-
     }
 
     Qt::WindowFlags windowFlags;
@@ -80,6 +80,7 @@ public:
     QString windowTitle;
     QRect geometry;
     QWindowContext *glContext;
+    QWindowSurface *surface;
 };
 
 

src/gui/painting/qwindowsurface.cpp

@@ -116,6 +116,8 @@ public:
 QWindowSurface::QWindowSurface(QWindow *window, bool /*setDefaultSurface*/)
     : d_ptr(new QWindowSurfacePrivate(window))
 {
+    if (window)
+        window->d_func()->surface = this;
 #if 0
     if (!QApplicationPrivate::runtime_graphics_system) {
         if (setDefaultSurface && window)

src/plugins/platforms/xcb/qxcbwindow.cpp

@@ -528,18 +528,12 @@ QPlatformGLContext *QXcbWindow::glContext() const
 
 void QXcbWindow::handleExposeEvent(const xcb_expose_event_t *event)
 {
-#if 0
+    QWindowSurface *surface = window()->surface();
-    QWidget *widget = window()->widget();
-    if (!widget)
-        return;
-
-    QWindowSurface *surface = widget->windowSurface();
     if (surface) {
         QRect rect(event->x, event->y, event->width, event->height);
 
-        surface->flush(widget, rect, QPoint());
+        surface->flush(window(), rect, QPoint());
     }
-#endif
 }
 
 void QXcbWindow::handleClientMessageEvent(const xcb_client_message_event_t *event)