QTreeView: now dragging lots of items is fast

4 files changed, 47 insertions, 2 deletions

diff --git a/src/gui/itemviews/qabstractitemview.cpp b/src/gui/itemviews/qabstractitemview.cpp
index a4a69c3..8887977 100644
--- a/src/gui/itemviews/qabstractitemview.cpp
+++ b/src/gui/itemviews/qabstractitemview.cpp
@@ -3918,7 +3918,7 @@ QPixmap QAbstractItemViewPrivate::renderToPixmap(const QModelIndexList &indexes,
     QStyleOptionViewItemV4 option = viewOptionsV4();
     option.state |= QStyle::State_Selected;
     for (int j = 0; j < paintPairs.count(); ++j) {
-        option.rect = paintPairs.at(j).first.translated(r->topLeft());
+        option.rect = paintPairs.at(j).first.translated(-r->topLeft());
         const QModelIndex &current = paintPairs.at(j).second;
         delegateForIndex(current)->paint(&painter, option, current);
     }
diff --git a/src/gui/itemviews/qlistview.cpp b/src/gui/itemviews/qlistview.cpp
index 9a94b31..40f28d4 100644
--- a/src/gui/itemviews/qlistview.cpp
+++ b/src/gui/itemviews/qlistview.cpp
@@ -722,7 +722,6 @@ QItemViewPaintPairs QListViewPrivate::draggablePaintPairs(const QModelIndexList
     QRect &rect = *r;
     const QRect viewportRect = viewport->rect();
     QItemViewPaintPairs ret;
-    intersectingSet(viewportRect);
     const QSet<QModelIndex> visibleIndexes = intersectingSet(viewportRect).toList().toSet();
     for (int i = 0; i < indexes.count(); ++i) {
         const QModelIndex &index = indexes.at(i);
diff --git a/src/gui/itemviews/qtreeview.cpp b/src/gui/itemviews/qtreeview.cpp
index f13ff0c..7084e6d 100644
--- a/src/gui/itemviews/qtreeview.cpp
+++ b/src/gui/itemviews/qtreeview.cpp
@@ -1321,6 +1321,50 @@ void QTreeViewPrivate::_q_modelDestroyed()
 }
 
 /*!
+  \reimp
+
+  We have a QTreeView way of knowing what elements are on the viewport
+*/
+QItemViewPaintPairs QTreeViewPrivate::draggablePaintPairs(const QModelIndexList &indexes, QRect *r) const
+{
+    Q_ASSERT(r);
+    return QAbstractItemViewPrivate::draggablePaintPairs(indexes, r);
+    Q_Q(const QTreeView);
+    QRect &rect = *r;
+    const QRect viewportRect = viewport->rect();
+    int itemOffset = 0;
+    int row = firstVisibleItem(&itemOffset);
+    QPair<int, int> startEnd = startAndEndColumns(viewportRect);
+    QVector<int> columns;
+    for (int i = startEnd.first; i <= startEnd.second; ++i) {
+        int logical = header->logicalIndex(i);
+        if (!header->isSectionHidden(logical))
+            columns += logical;
+    }
+    QSet<QModelIndex> visibleIndexes;
+    for (; itemOffset < viewportRect.bottom() && row < viewItems.count(); ++row) {
+        const QModelIndex &index = viewItems.at(row).index;
+        for (int colIndex = 0; colIndex < columns.count(); ++colIndex)
+            visibleIndexes += index.sibling(index.row(), columns.at(colIndex));
+        itemOffset += itemHeight(row);
+    }
+
+    //now that we have the visible indexes, we can try to find those which are selected
+    QItemViewPaintPairs ret;
+    for (int i = 0; i < indexes.count(); ++i) {
+        const QModelIndex &index = indexes.at(i);
+        if (visibleIndexes.contains(index)) {
+            const QRect current = q->visualRect(index);
+            ret += qMakePair(current, index);
+            rect |= current;
+        }
+    }
+    rect &= viewportRect;
+    return ret;
+}
+
+
+/*!
   \since 4.2
   Draws the part of the tree intersecting the given \a region using the specified
   \a painter.
diff --git a/src/gui/itemviews/qtreeview_p.h b/src/gui/itemviews/qtreeview_p.h
index 6fb2e41..546dc75 100644
--- a/src/gui/itemviews/qtreeview_p.h
+++ b/src/gui/itemviews/qtreeview_p.h
@@ -89,6 +89,8 @@ public:
     ~QTreeViewPrivate() {}
     void initialize();
 
+    QItemViewPaintPairs draggablePaintPairs(const QModelIndexList &indexes, QRect *r) const;
+
 #ifndef QT_NO_ANIMATION
     struct AnimatedOperation : public QVariantAnimation
     {