Don't layout multiple times when an ancestor becomes (in)visible.

It is also only necessary to omit positioning an item if it is
explicitly not visible.

Task-number: QTBUG-11236

2 files changed, 21 insertions, 13 deletions

diff --git a/src/declarative/graphicsitems/qdeclarativepositioners.cpp b/src/declarative/graphicsitems/qdeclarativepositioners.cpp
index 20cc46b..18618ab 100644
--- a/src/declarative/graphicsitems/qdeclarativepositioners.cpp
+++ b/src/declarative/graphicsitems/qdeclarativepositioners.cpp
@@ -219,6 +219,7 @@ void QDeclarativeBasePositioner::prePositioning()
         QDeclarativeItem *child = qobject_cast<QDeclarativeItem *>(children.at(ii));
         if (!child)
             continue;
+        QDeclarativeItemPrivate *childPrivate = static_cast<QDeclarativeItemPrivate*>(QGraphicsItemPrivate::get(child));
         PositionedItem *item = 0;
         PositionedItem posItem(child);
         int wIdx = oldItems.find(posItem);
@@ -227,11 +228,13 @@ void QDeclarativeBasePositioner::prePositioning()
             positionedItems.append(posItem);
             item = &positionedItems[positionedItems.count()-1];
             item->isNew = true;
-            if (child->opacity() <= 0.0 || !child->isVisible())
+            if (child->opacity() <= 0.0 || childPrivate->explicitlyHidden)
                 item->isVisible = false;
         } else {
             item = &oldItems[wIdx];
-            if (child->opacity() <= 0.0 || !child->isVisible()) {
+            // Items are only omitted from positioning if they are explicitly hidden
+            // i.e. their positioning is not affected if an ancestor is hidden.
+            if (child->opacity() <= 0.0 || childPrivate->explicitlyHidden) {
                 item->isVisible = false;
             } else if (!item->isVisible) {
                 item->isVisible = true;
@@ -299,6 +302,12 @@ void QDeclarativeBasePositioner::finishApplyTransitions()
     d->moveActions.clear();
 }
 
+static inline bool isInvisible(QDeclarativeItem *child)
+{
+    QDeclarativeItemPrivate *childPrivate = static_cast<QDeclarativeItemPrivate*>(QGraphicsItemPrivate::get(child));
+    return child->opacity() == 0.0 || childPrivate->explicitlyHidden || !child->width() || !child->height();
+}
+
 /*!
   \qmlclass Column QDeclarativeColumn
     \since 4.7
@@ -416,11 +425,6 @@ QDeclarativeColumn::QDeclarativeColumn(QDeclarativeItem *parent)
 {
 }
 
-static inline bool isInvisible(QDeclarativeItem *child)
-{
-    return child->opacity() == 0.0 || !child->isVisible() || !child->width() || !child->height();
-}
-
 void QDeclarativeColumn::doPositioning(QSizeF *contentSize)
 {
     int voffset = 0;
diff --git a/src/declarative/graphicsitems/qdeclarativepositioners_p_p.h b/src/declarative/graphicsitems/qdeclarativepositioners_p_p.h
index 04f0181..822079b 100644
--- a/src/declarative/graphicsitems/qdeclarativepositioners_p_p.h
+++ b/src/declarative/graphicsitems/qdeclarativepositioners_p_p.h
@@ -100,18 +100,23 @@ public:
     bool doingPositioning : 1;
     bool anchorConflict : 1;
 
-    virtual void itemSiblingOrderChanged(QDeclarativeItem* other)
+    void schedulePositioning()
     {
         Q_Q(QDeclarativeBasePositioner);
-        Q_UNUSED(other);
         if(!queuedPositioning){
-            //Delay is due to many children often being reordered at once
-            //And we only want to reposition them all once
             QTimer::singleShot(0,q,SLOT(prePositioning()));
             queuedPositioning = true;
         }
     }
 
+    virtual void itemSiblingOrderChanged(QDeclarativeItem* other)
+    {
+        Q_UNUSED(other);
+        //Delay is due to many children often being reordered at once
+        //And we only want to reposition them all once
+        schedulePositioning();
+    }
+
     void itemGeometryChanged(QDeclarativeItem *, const QRectF &newGeometry, const QRectF &oldGeometry)
     {
         Q_Q(QDeclarativeBasePositioner);
@@ -120,8 +125,7 @@ public:
     }
     virtual void itemVisibilityChanged(QDeclarativeItem *)
     {
-        Q_Q(QDeclarativeBasePositioner);
-        q->prePositioning();
+        schedulePositioning();
     }
     virtual void itemOpacityChanged(QDeclarativeItem *)
     {