Speedup item-lookup in Graphics View.

We don't have to do a stable sort anymore because the lessThan operator
now accounts for the insertion order. This also means we don't have to
sort all top-level items to preserve the insertion order in
QGraphicsScenePrivate::topLevelItemsInStackingOrder.

Reviewed-by: Andreas

1 files changed, 8 insertions, 0 deletions

diff --git a/src/gui/graphicsview/qgraphicsscene_p.h b/src/gui/graphicsview/qgraphicsscene_p.h
index 4842e72..23b0dd5 100644
--- a/src/gui/graphicsview/qgraphicsscene_p.h
+++ b/src/gui/graphicsview/qgraphicsscene_p.h
@@ -234,6 +234,14 @@ public:
         item->d_ptr->ignoreOpacity = 0;
     }
 
+    inline void ensureSortedTopLevelItems()
+    {
+        if (needSortTopLevelItems) {
+            qSort(topLevelItems.begin(), topLevelItems.end(), qt_notclosestLeaf);
+            needSortTopLevelItems = false;
+        }
+    }
+
     QStyle *style;
     QFont font;
     void setFont_helper(const QFont &font);