Bug 547577 - nsWindow::Scroll must be updated for widget QT port. r=dougt

widget/src/qt/mozqwidget.h

@@ -107,6 +107,10 @@ protected:
             mTopLevelWidget->setGeometry( 0.0, 0.0,
                 static_cast<qreal>(aEvent->size().width()),
                 static_cast<qreal>(aEvent->size().height()));
+            // resize scene rect to vieport size,
+            // to avoid extra scrolling from QAbstractScrollable
+            setSceneRect(viewport()->rect());
+
         }
         QGraphicsView::resizeEvent(aEvent);
     }

widget/src/qt/nsWindow.cpp

@@ -231,8 +231,15 @@ UpdateOffScreenBuffers(QSize aSize, int aDepth)
     if (!gBufferPixmap)
         return false;
 
-    if (gfxQtPlatform::GetPlatform()->GetRenderMode() == gfxQtPlatform::RENDER_XLIB)
+    if (gfxQtPlatform::GetPlatform()->GetRenderMode() == gfxQtPlatform::RENDER_XLIB) {
+        if (!gBufferPixmap->handle()) {
+            NS_ERROR("XDrawable must be available for QPixmap in RENDER_XLIB mode");
+            delete gBufferPixmap;
+            gBufferPixmap = nsnull;
+            return false;
+        }
         return true;
+    }
 
     // Check if system depth has related gfxImage format
     gfxASurface::gfxImageFormat format =
@@ -653,7 +660,10 @@ nsWindow::Update()
     if (!mWidget)
         return NS_OK;
 
-    mWidget->update(); // FIXME  This call cause update for whole window on each scroll event
+    // Just proceed all pending paints
+    if (GetViewWidget())
+        GetViewWidget()->repaint();
+
     return NS_OK;
 }
 
@@ -688,9 +698,21 @@ nsWindow::Scroll(const nsIntPoint& aDelta,
 
     for (BlitRectIter iter(aDelta, aDestRects); !iter.IsDone(); ++iter) {
         const nsIntRect & r = iter.Rect();
-        QRect rect(r.x - aDelta.x, r.y - aDelta.y, r.width, r.height);
+        QRegion goodReg(QRect(r.x, r.y, r.width, r.height));
+        goodReg = goodReg.subtracted(mDirtyScrollArea);
+
+        const QVector<QRect> myRects = goodReg.rects();
+        for (QVector<QRect>::const_iterator it = myRects.constBegin(); it < myRects.constEnd(); ++it) {
+            QRect rect(*it);
             mWidget->scroll(aDelta.x, aDelta.y, rect);
+            // Calculate dirty area which is need to be updated
+            QRegion dirtyReg(rect);
+            rect.translate(aDelta.x, aDelta.y);
+            dirtyReg = dirtyReg.subtracted(rect);
+            mDirtyScrollArea = mDirtyScrollArea.united(dirtyReg);
         }
+    }
+
     ConfigureChildren(aConfigurations);
 
     // Show windows again...
@@ -961,20 +983,13 @@ nsWindow::DoPaint(QPainter* aPainter, const QStyleOptionGraphicsItem* aOption)
     if (!mWidget)
         return nsEventStatus_eIgnore;
 
-    static NS_DEFINE_CID(kRegionCID, NS_REGION_CID);
-
-    nsCOMPtr<nsIRegion> updateRegion = do_CreateInstance(kRegionCID);
-    if (!updateRegion)
-        return nsEventStatus_eIgnore;
-
     QRectF r;
-
     if (aOption)
         r = aOption->exposedRect;
     else
         r = mWidget->boundingRect();
 
-    updateRegion->SetTo( (int)r.x(), (int)r.y(), (int)r.width(), (int)r.height() );
+    mDirtyScrollArea = QRegion();
 
     gfxQtPlatform::RenderMode renderMode = gfxQtPlatform::GetPlatform()->GetRenderMode();
     // Prepare offscreen buffers if RenderMode Xlib or Image
@@ -1009,8 +1024,8 @@ nsWindow::DoPaint(QPainter* aPainter, const QStyleOptionGraphicsItem* aOption)
     nsIntRect rect(r.x(), r.y(), r.width(), r.height());
     event.refPoint.x = r.x();
     event.refPoint.y = r.y();
-    event.rect = nsnull;
+    event.rect = &rect;
-    event.region = updateRegion;
+    event.region = nsnull;
     event.renderingContext = rc;
 
     nsEventStatus status = DispatchEvent(&event);
@@ -1025,7 +1040,10 @@ nsWindow::DoPaint(QPainter* aPainter, const QStyleOptionGraphicsItem* aOption)
 
     LOGDRAW(("[%p] draw done\n", this));
 
-    if (renderMode == gfxQtPlatform::RENDER_SHARED_IMAGE) {
+    // If handle not available for QPixmap it means that we are using
+    //   "-graphicssystem raster" rendering backend
+    // in raster mode we can just wrap gBufferImage as QImage and paint directly
+    if (renderMode == gfxQtPlatform::RENDER_SHARED_IMAGE && gBufferPixmap->handle()) {
         if (gNeedColorConversion) {
             pixman_image_t *src_image = NULL;
             pixman_image_t *dst_image = NULL;
@@ -1057,13 +1075,25 @@ nsWindow::DoPaint(QPainter* aPainter, const QStyleOptionGraphicsItem* aOption)
         gcv.graphics_exposures = False;
         GC gc = XCreateGC (disp, gBufferPixmap->handle(), GCGraphicsExposures, &gcv);
         XShmPutImage(disp, gBufferPixmap->handle(), gc, gBufferImage->image(),
-                     0, 0, 0, 0, gBufferImage->GetSize().width, gBufferImage->GetSize().height,
+                     rect.x, rect.y, rect.x, rect.y, rect.width, rect.height,
                      False);
         XFreeGC (disp, gc);
     }
 
-    if (renderMode != gfxQtPlatform::RENDER_QPAINTER)
+    if (renderMode != gfxQtPlatform::RENDER_QPAINTER) {
-        aPainter->drawPixmap(QPoint(0, 0), *gBufferPixmap);
+        if (gBufferPixmap->handle())
+            aPainter->drawPixmap(QPoint(rect.x, rect.y), *gBufferPixmap,
+                                 QRect(rect.x, rect.y, rect.width, rect.height));
+        else {
+            QImage img(gBufferImage->Data(),
+                       gBufferImage->Width(),
+                       gBufferImage->Height(),
+                       gBufferImage->Stride(),
+                       QImage::Format_RGB32);
+            aPainter->drawImage(QPoint(rect.x, rect.y), img,
+                                QRect(rect.x, rect.y, rect.width, rect.height));
+        }
+    }
 
     ctx = nsnull;
     targetSurface = nsnull;
@@ -1964,6 +1994,10 @@ nsWindow::createQWidget(MozQWidget *parent, nsWidgetInitData *aInitData)
     if (mScene && newView) {
         mScene->addItem(widget);
         newView->setTopLevel(widget);
+#if (QT_VERSION >= QT_VERSION_CHECK(4, 6, 0))
+        // Top level widget is just container, and should not be painted
+        widget->setFlag(QGraphicsItem::ItemHasNoContents);
+#endif
     }
 
     if (mWindowType == eWindowType_popup) {

widget/src/qt/nsWindow.h

@@ -354,6 +354,8 @@ private:
     }
     PRInt32 mQCursor;
 
+    // Remember dirty area caused by ::Scroll
+    QRegion mDirtyScrollArea;
 };
 
 class nsChildWindow : public nsWindow