2 files changed, 95 insertions, 8 deletions

diff --git a/src/gui/graphicsview/qgraphicsview.cpp b/src/gui/graphicsview/qgraphicsview.cpp
index c4297df..418638f 100644
--- a/src/gui/graphicsview/qgraphicsview.cpp
+++ b/src/gui/graphicsview/qgraphicsview.cpp
@@ -1046,13 +1046,24 @@ void QGraphicsViewPrivate::freeStyleOptionsArray(QStyleOptionGraphicsItem *array
 
 extern QPainterPath qt_regionToPath(const QRegion &region);
 
+/*!
+    ### Adjustments in findItems: mapToScene(QRect) forces us to adjust the
+    input rectangle by (0, 0, 1, 1), because it uses QRect::bottomRight()
+    (etc) when mapping the rectangle to a polygon (which is _wrong_). In
+    addition, as QGraphicsItem::boundingRect() is defined in logical space,
+    but the default pen for QPainter is cosmetic with a width of 0, QPainter
+    is at risk of painting 1 pixel outside the bounding rect. Therefore we
+    must search for items with an adjustment of (-1, -1, 1, 1).
+*/
 QList<QGraphicsItem *> QGraphicsViewPrivate::findItems(const QRegion &exposedRegion, bool *allItems) const
 {
     Q_Q(const QGraphicsView);
-    const QPainterPath exposedPath(qt_regionToPath(exposedRegion));
-    const QPainterPath exposedScenePath(q->mapToScene(exposedPath));
 
-    if (exposedScenePath.contains(scene->d_func()->growingItemsBoundingRect)) {
+    // Step 1) If all items are contained within the expose region, then
+    // return a list of all visible items.
+    const QRectF exposedRegionSceneBounds = q->mapToScene(exposedRegion.boundingRect().adjusted(-1, -1, 2, 2))
+                                            .boundingRect();
+    if (exposedRegionSceneBounds.contains(scene->d_func()->growingItemsBoundingRect)) {
         Q_ASSERT(allItems);
         *allItems = true;
 
@@ -1072,12 +1083,27 @@ QList<QGraphicsItem *> QGraphicsViewPrivate::findItems(const QRegion &exposedReg
         return itemList;
     }
 
+    // Step 2) If the expose region is a simple rect and the view is only
+    // translated or scaled, search for items using
+    // QGraphicsScene::items(QRectF).
+    bool simpleRectLookup =  (scene->d_func()->largestUntransformableItem.isNull()
+                              && exposedRegion.numRects() == 1 && matrix.type() <= QTransform::TxScale);
+    if (simpleRectLookup) {
+        return scene->d_func()->items_helper(exposedRegionSceneBounds,
+                                             Qt::IntersectsItemBoundingRect,
+                                             Qt::DescendingOrder);
+    }
+
+    // If the region is complex or the view has a complex transform, adjust
+    // the expose region, convert it to a path, and then search for items
+    // using QGraphicsScene::items(QPainterPath);
+    QRegion adjustedRegion;
+    foreach (const QRect &r, exposedRegion.rects())
+        adjustedRegion += r.adjusted(-1, -1, 1, 1);
+
+    const QPainterPath exposedPath(qt_regionToPath(adjustedRegion));
     if (scene->d_func()->largestUntransformableItem.isNull()) {
-        if (exposedRegion.numRects() == 1 && matrix.type() <= QTransform::TxScale) {
-            return scene->d_func()->items_helper(exposedScenePath.controlPointRect(),
-                                                 Qt::IntersectsItemBoundingRect,
-                                                 Qt::DescendingOrder);
-        }
+        const QPainterPath exposedScenePath(q->mapToScene(exposedPath));
         return scene->d_func()->items_helper(exposedScenePath,
                                              Qt::IntersectsItemBoundingRect,
                                              Qt::DescendingOrder);
diff --git a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
index 4368e76..412c6c5 100644
--- a/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
+++ b/tests/auto/qgraphicsview/tst_qgraphicsview.cpp
@@ -155,6 +155,8 @@ private slots:
     void fitInView();
     void itemsAtPoint();
     void itemsInRect();
+    void itemsInRect_cosmeticAdjust_data();
+    void itemsInRect_cosmeticAdjust();
     void itemsInPoly();
     void itemsInPath();
     void itemAt();
@@ -1310,6 +1312,65 @@ void tst_QGraphicsView::itemsInRect()
     QCOMPARE(items.takeFirst()->zValue(), qreal(3));
 }
 
+class CountPaintItem : public QGraphicsRectItem
+{
+public:
+    int numPaints;
+
+    CountPaintItem(const QRectF &rect)
+        : QGraphicsRectItem(rect), numPaints(0)
+    { }
+
+    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0)
+    {
+        ++numPaints;
+        QGraphicsRectItem::paint(painter, option, widget);
+    }
+};
+
+void tst_QGraphicsView::itemsInRect_cosmeticAdjust_data()
+{
+    QTest::addColumn<QRect>("updateRect");
+    QTest::addColumn<int>("numPaints");
+
+    QTest::newRow("nil") << QRect() << 1;
+    QTest::newRow("0, 0, 300, 100") << QRect(0, 0, 300, 100) << 1;
+    QTest::newRow("0, 0, 100, 300") << QRect(0, 0, 100, 300) << 1;
+    QTest::newRow("200, 0, 100, 300") << QRect(200, 0, 100, 300) << 1;
+    QTest::newRow("0, 200, 300, 100") << QRect(0, 200, 300, 100) << 1;
+    QTest::newRow("0, 0, 300, 99") << QRect(0, 0, 300, 99) << 0;
+    QTest::newRow("0, 0, 99, 300") << QRect(0, 0, 99, 300) << 0;
+    QTest::newRow("201, 0, 99, 300") << QRect(201, 0, 99, 300) << 0;
+    QTest::newRow("0, 201, 300, 99") << QRect(0, 201, 300, 99) << 0;
+}
+
+void tst_QGraphicsView::itemsInRect_cosmeticAdjust()
+{
+    QFETCH(QRect, updateRect);
+    QFETCH(int, numPaints);
+    
+    QGraphicsScene scene(-100, -100, 200, 200);
+    CountPaintItem *rect = new CountPaintItem(QRectF(-50, -50, 100, 100));
+    scene.addItem(rect);
+
+    QGraphicsView view(&scene);
+    view.setFrameStyle(0);
+    view.resize(300, 300);
+    view.show();
+#ifdef Q_WS_X11
+    qt_x11_wait_for_window_manager(&view);
+#endif
+    QTest::qWait(125);
+
+    rect->numPaints = 0;
+    if (updateRect.isNull())
+        view.viewport()->update();
+    else
+        view.viewport()->update(updateRect);
+    qApp->processEvents();
+    QCOMPARE(rect->numPaints, numPaints);
+}
+
 void tst_QGraphicsView::itemsInPoly()
 {
     QGraphicsScene scene;