Painting artifacts in QGraphicsView.

Problem appears in the chip demo when clicking an item while scrolling the
view using the mouse wheel. The problem was that we didn't translate the
the item's old painted view rect.

There was also a problem when enabling the DontAdjustForAntialiasing flag,
causing an item to not redraw its edges. We have to adjust the rectangle
by (-1, -1, 1, 1) since QRect() and QRectF() behaves differently.

Auto-test (made by Andreas) included.

Reviewed-by: Andreas

4 files changed, 83 insertions, 10 deletions

diff --git a/src/gui/graphicsview/qgraphicsscene.cpp b/src/gui/graphicsview/qgraphicsscene.cpp
index 1c48675..55d8a1d 100644
--- a/src/gui/graphicsview/qgraphicsscene.cpp
+++ b/src/gui/graphicsview/qgraphicsscene.cpp
@@ -5269,7 +5269,9 @@ void QGraphicsScenePrivate::markDirty(QGraphicsItem *item, const QRectF &rect, b
 
         for (int i = 0; i < views.size(); ++i) {
             QGraphicsViewPrivate *viewPrivate = views.at(i)->d_func();
-            viewPrivate->updateRect(item->d_ptr->paintedViewBoundingRects.value(viewPrivate->viewport));
+            QRect rect = item->d_ptr->paintedViewBoundingRects.value(viewPrivate->viewport);
+            rect.translate(viewPrivate->dirtyScrollOffset);
+            viewPrivate->updateRect(rect);
         }
         return;
     }
@@ -5350,7 +5352,9 @@ void QGraphicsScenePrivate::processDirtyItemsRecursive(QGraphicsItem *item, bool
 
                 if (item->d_ptr->paintedViewBoundingRectsNeedRepaint) {
                     wasDirtyParentViewBoundingRects = true;
-                    viewPrivate->updateRect(item->d_ptr->paintedViewBoundingRects.value(viewPrivate->viewport));
+                    QRect rect = item->d_ptr->paintedViewBoundingRects.value(viewPrivate->viewport);
+                    rect.translate(viewPrivate->dirtyScrollOffset);
+                    viewPrivate->updateRect(rect);
                 }
 
                 if (!item->d_ptr->dirty)
diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index 4a32ee5..a72aa5a 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -812,7 +812,7 @@ void QGraphicsViewPrivate::processPendingUpdates()
 
     if (viewportUpdateMode == QGraphicsView::BoundingRectViewportUpdate) {
         if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing)
-            viewport->update(dirtyBoundingRect);
+            viewport->update(dirtyBoundingRect.adjusted(-1, -1, 1, 1));
         else
             viewport->update(dirtyBoundingRect.adjusted(-2, -2, 2, 2));
     } else {
@@ -843,14 +843,16 @@ void QGraphicsViewPrivate::updateRegion(const QRegion &r)
         break;
     case QGraphicsView::SmartViewportUpdate: // ### DEPRECATE
     case QGraphicsView::MinimalViewportUpdate:
-        if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing) {
-            dirtyRegion += r;
-        } else {
-            const QVector<QRect> &rects = r.rects();
-            for (int i = 0; i < rects.size(); ++i)
+    {
+        const QVector<QRect> &rects = r.rects();
+        for (int i = 0; i < rects.size(); ++i) {
+            if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing)
+                dirtyRegion += rects.at(i).adjusted(-1, -1, 1, 1);
+            else
                 dirtyRegion += rects.at(i).adjusted(-2, -2, 2, 2);
         }
         break;
+    }
     case QGraphicsView::NoViewportUpdate:
         // Unreachable
         break;
@@ -878,7 +880,7 @@ void QGraphicsViewPrivate::updateRect(const QRect &r)
     case QGraphicsView::SmartViewportUpdate: // ### DEPRECATE
     case QGraphicsView::MinimalViewportUpdate:
         if (optimizationFlags & QGraphicsView::DontAdjustForAntialiasing)
-            dirtyRegion += r;
+            dirtyRegion += r.adjusted(-1, -1, 1, 1);
         else
             dirtyRegion += r.adjusted(-2, -2, 2, 2);
         break;
@@ -2678,6 +2680,7 @@ bool QGraphicsView::viewportEvent(QEvent *event)
     case QEvent::Paint:
         // Reset full update
         d->fullUpdatePending = false;
+        d->dirtyScrollOffset = QPoint();
         if (d->scene) {
             // Check if this view reimplements the updateScene slot; if it
             // does, we can't do direct update delivery and have to fall back
@@ -3375,7 +3378,6 @@ void QGraphicsView::scrollContentsBy(int dx, int dy)
 
     if (d->viewportUpdateMode != QGraphicsView::NoViewportUpdate) {
         if (d->viewportUpdateMode != QGraphicsView::FullViewportUpdate) {
-            d->dirtyRegion.translate(dx, dy);
             if (d->accelerateScrolling) {
 #ifndef QT_NO_RUBBERBAND
                 // Update new and old rubberband regions
@@ -3385,6 +3387,9 @@ void QGraphicsView::scrollContentsBy(int dx, int dy)
                     viewport()->update(rubberBandRegion);
                 }
 #endif
+                d->dirtyScrollOffset.rx() += dx;
+                d->dirtyScrollOffset.ry() += dy;
+                d->dirtyRegion.translate(dx, dy);
                 viewport()->scroll(dx, dy);
             } else {
                 d->updateAll();
diff --git a/src/gui/graphicsview/qgraphicsview_p.h b/src/gui/graphicsview/qgraphicsview_p.h
index 00f3035..a6f0d04 100644
--- a/src/gui/graphicsview/qgraphicsview_p.h
+++ b/src/gui/graphicsview/qgraphicsview_p.h
@@ -94,6 +94,7 @@ public:
     QPoint mousePressScreenPoint;
     QPointF lastMouseMoveScenePoint;
     QPoint lastMouseMoveScreenPoint;
+    QPoint dirtyScrollOffset;
     Qt::MouseButton mousePressButton;
     QTransform matrix;
     bool identityMatrix;
diff --git a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
index 5167682..06b4a78 100644
--- a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
@@ -188,6 +188,8 @@ private slots:
     void embeddedViews();
     void scrollAfterResize_data();
     void scrollAfterResize();
+    void moveItemWhileScrolling_data();
+    void moveItemWhileScrolling();
     void centerOnDirtyItem();
     void mouseTracking();
     void mouseTracking2();
@@ -3045,6 +3047,67 @@ void tst_QGraphicsView::scrollAfterResize()
     QCOMPARE(view.viewportTransform(), x3);
 }
 
+void tst_QGraphicsView::moveItemWhileScrolling_data()
+{
+    QTest::addColumn<bool>("adjustForAntialiasing");
+
+    QTest::newRow("no adjust") << false;
+    QTest::newRow("adjust") << true;
+}
+
+void tst_QGraphicsView::moveItemWhileScrolling()
+{
+    QFETCH(bool, adjustForAntialiasing);
+
+    class MoveItemScrollView : public QGraphicsView
+    {
+    public:
+        MoveItemScrollView()
+        {
+            setScene(new QGraphicsScene(0, 0, 1000, 1000));
+            rect = scene()->addRect(0, 0, 10, 10);
+            rect->setPos(50, 50);
+        }
+        QRegion lastPaintedRegion;
+        QGraphicsItem *rect;
+    protected:
+        void paintEvent(QPaintEvent *event)
+        {
+            lastPaintedRegion = event->region();
+            QGraphicsView::paintEvent(event);
+        }
+    };
+
+    MoveItemScrollView view;
+    view.setFrameStyle(0);
+    view.setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    view.setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
+    view.setResizeAnchor(QGraphicsView::NoAnchor);
+    view.setTransformationAnchor(QGraphicsView::NoAnchor);
+    if (!adjustForAntialiasing)
+        view.setOptimizationFlag(QGraphicsView::DontAdjustForAntialiasing);
+    view.show();
+    view.resize(200, 200);
+#ifdef Q_WS_X11
+    qt_x11_wait_for_window_manager(&view);
+#endif
+    QTest::qWait(100);
+
+    view.lastPaintedRegion = QRegion();
+    view.horizontalScrollBar()->setValue(view.horizontalScrollBar()->value() + 10);
+    view.rect->moveBy(0, 10);
+    QTest::qWait(100);
+
+    QRegion expectedRegion;
+    expectedRegion += QRect(0, 0, 200, 200);
+    expectedRegion -= QRect(0, 0, 190, 200);
+    int a = adjustForAntialiasing ? 2 : 1;
+    expectedRegion += QRect(40, 50, 10, 10).adjusted(-a, -a, a, a);
+    expectedRegion += QRect(40, 60, 10, 10).adjusted(-a, -a, a, a);
+
+    QCOMPARE(view.lastPaintedRegion, expectedRegion);
+}
+
 void tst_QGraphicsView::centerOnDirtyItem()
 {
     QGraphicsView view;