Use PlatformNativeInterface to obtain backingStore's dc

Change-Id: I6ec2fc0b8e7696fdfe4468920228df2d21c933fd
Reviewed-on: http://codereview.qt.nokia.com/1501
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@nokia.com>

src/gui/kernel/qplatformnativeinterface_qpa.cpp

@@ -57,4 +57,11 @@ void *QPlatformNativeInterface::nativeResourceForContext(const QByteArray &resou
     return 0;
 }
 
+void * QPlatformNativeInterface::nativeResourceForBackingStore(const QByteArray &resource, QBackingStore *backingStore)
+{
+    Q_UNUSED(resource);
+    Q_UNUSED(backingStore);
+    return 0;
+}
+
 QT_END_NAMESPACE

src/gui/kernel/qplatformnativeinterface_qpa.h

@@ -52,12 +52,14 @@ QT_MODULE(Gui)
 
 class QGuiGLContext;
 class QWindow;
+class QBackingStore;
 
 class Q_GUI_EXPORT QPlatformNativeInterface
 {
 public:
     virtual void *nativeResourceForContext(const QByteArray &resource, QGuiGLContext *context);
     virtual void *nativeResourceForWindow(const QByteArray &resource, QWindow *window);
+    virtual void *nativeResourceForBackingStore(const QByteArray &resource, QBackingStore *backingStore);
 };
 
 QT_END_NAMESPACE

src/gui/painting/qbackingstore.cpp

@@ -247,4 +247,9 @@ void Q_GUI_EXPORT qt_scrollRectInImage(QImage &img, const QRect &rect, const QPo
     }
 }
 
+QPlatformBackingStore *QBackingStore::handle() const
+{
+    return d_ptr->platformBackingStore;
+}
+
 QT_END_NAMESPACE

src/gui/painting/qbackingstore.h

@@ -54,6 +54,7 @@ class QRect;
 class QPoint;
 class QImage;
 class QBackingStorePrivate;
+class QPlatformBackingStore;
 
 class Q_GUI_EXPORT QBackingStore
 {
@@ -81,6 +82,8 @@ public:
     QRegion staticContents() const;
     bool hasStaticContents() const;
 
+    QPlatformBackingStore *handle() const;
+
 private:
     QScopedPointer<QBackingStorePrivate> d_ptr;
 };

src/widgets/dialogs/qwizard_win.cpp

@@ -232,7 +232,9 @@ void QVistaBackButton::paintEvent(QPaintEvent *)
     else if (underMouse())
         state = WIZ_NAV_BB_HOT;
 
-   pDrawThemeBackground(theme, p.paintEngine()->getDC(), WIZ_NAV_BACKBUTTON, state, &clipRect, &clipRect); 
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    HDC hdc = static_cast<HDC>(nativeInterface->nativeResourceForBackingStore("getDC", backingStore()));
+    pDrawThemeBackground(theme, hdc, WIZ_NAV_BACKBUTTON, state, &clipRect, &clipRect);
 }
 
 /******************************************************************************
@@ -318,12 +320,14 @@ bool QVistaHelper::setDWMTitleBar(TitleBarChangeType type)
 
 void QVistaHelper::drawTitleBar(QPainter *painter)
 {
-    HDC hdc = static_cast<QRasterPaintEngine *>(painter->paintEngine())->getDC();
+    Q_ASSERT(backButton_);
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    QBackingStore *backingStore = backButton_->backingStore();
+    HDC hdc = static_cast<HDC>(nativeInterface->nativeResourceForBackingStore("getDC", backingStore));
 
     if (vistaState() == VistaAero)
         drawBlackRect(QRect(0, 0, wizard->width(),
                             titleBarSize() + topOffset()), hdc);
-    Q_ASSERT(backButton_);
     const int btnTop = backButton_->mapToParent(QPoint()).y();
     const int btnHeight = backButton_->size().height();
     const int verticalCenter = (btnTop + btnHeight / 2) - 1;

src/widgets/styles/qwindowsxpstyle.cpp

@@ -190,17 +190,17 @@ RECT XPThemeData::toRECT(const QRect &qr)
     Returns the native region of a part, if the part is considered
     transparent. The region is scaled to the parts size (rect).
 */
-HRGN XPThemeData::mask()
+HRGN XPThemeData::mask(QWidget *widget)
 {
     if (!pIsThemeBackgroundPartiallyTransparent(handle(), partId, stateId))
         return 0;
 
     HRGN hrgn;
-    HDC dc = painter == 0 ? 0 : painter->paintEngine()->getDC();
+    QBackingStore *backingStore = widget->backingStore();
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    HDC dc = static_cast<HDC>(nativeInterface->nativeResourceForBackingStore("getDC", backingStore));
     RECT nativeRect = toRECT(rect);
     pGetThemeBackgroundRegion(handle(), dc, partId, stateId, &nativeRect, &hrgn);
-    if (dc)
-        painter->paintEngine()->releaseDC(dc);
     return hrgn;
 }
 
@@ -505,7 +505,7 @@ QRegion QWindowsXPStylePrivate::region(XPThemeData &themeData)
 */
 void QWindowsXPStylePrivate::setTransparency(QWidget *widget, XPThemeData &themeData)
 {
-    HRGN hrgn = themeData.mask();
+    HRGN hrgn = themeData.mask(widget);
     if (hrgn && widget)
         SetWindowRgn(winId(widget), hrgn, true);
 }
@@ -657,7 +657,10 @@ void QWindowsXPStylePrivate::drawBackground(XPThemeData &themeData)
         translucentToplevel = win->testAttribute(Qt::WA_TranslucentBackground);
     }
 
-    bool useFallback = painter->paintEngine()->getDC() == 0
+    QBackingStore *backingStore = themeData.widget->backingStore();
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    HDC dc = static_cast<HDC>(nativeInterface->nativeResourceForBackingStore("getDC", backingStore ));
+    bool useFallback = dc == 0
                        || painter->opacity() != 1.0
                        || themeData.rotate
                        || complexXForm
@@ -681,7 +684,9 @@ void QWindowsXPStylePrivate::drawBackground(XPThemeData &themeData)
 void QWindowsXPStylePrivate::drawBackgroundDirectly(XPThemeData &themeData)
 {
     QPainter *painter = themeData.painter;
-    HDC dc = painter->paintEngine()->getDC();
+    QBackingStore *backingStore= themeData.widget->backingStore();
+    QPlatformNativeInterface *nativeInterface = QGuiApplication::platformNativeInterface();
+    HDC dc = static_cast<HDC>(nativeInterface->nativeResourceForBackingStore("getDC", backingStore));
 
     QPoint redirectionDelta(int(painter->deviceMatrix().dx()),
                             int(painter->deviceMatrix().dy()));

src/widgets/styles/qwindowsxpstyle_p.h

@@ -216,7 +216,7 @@ public:
           noContent(false), rotate(0), rect(r)
     {}
 
-    HRGN mask();
+    HRGN mask(QWidget *widget);
     HTHEME handle();
 
     RECT toRECT(const QRect &qr);