Quick: Do not calculate the difference in a geometryChange

This difference is only used by the ListView, so calculating it and
storing it (on the stack) introduces a penalty for all items. As the new
geometry is already applied, the old geometry is passed along. This has
the added advantage that the ListView does not have to re-calculate that
either. This fixes a performance regression.

Change-Id: Id5e67bb663a5b11a55ec15ff24ca5b213d1fcef5
Reviewed-by: Gunnar Sletta <gunnar@sletta.org>

9 files changed, 28 insertions, 32 deletions

diff --git a/src/quick/items/qquickitem.cpp b/src/quick/items/qquickitem.cpp
index 1e60ef8c02..13b75c0482 100644
--- a/src/quick/items/qquickitem.cpp
+++ b/src/quick/items/qquickitem.cpp
@@ -3658,21 +3658,17 @@ void QQuickItem::geometryChanged(const QRectF &newGeometry, const QRectF &oldGeo
         QQuickAnchorsPrivate::get(d->_anchors)->updateMe();
 
     QQuickGeometryChange change;
-    QRectF diff(newGeometry.x() - oldGeometry.x(),
-                newGeometry.y() - oldGeometry.y(),
-                newGeometry.width() - oldGeometry.width(),
-                newGeometry.height() - oldGeometry.height());
-    change.setXChange(diff.x() != 0);
-    change.setYChange(diff.y() != 0);
-    change.setWidthChange(diff.width() != 0);
-    change.setHeightChange(diff.height() != 0);
+    change.setXChange(newGeometry.x() != oldGeometry.x());
+    change.setYChange(newGeometry.y() != oldGeometry.y());
+    change.setWidthChange(newGeometry.width() != oldGeometry.width());
+    change.setHeightChange(newGeometry.height() != oldGeometry.height());
 
     if (!d->changeListeners.isEmpty()) {
         const auto listeners = d->changeListeners; // NOTE: intentional copy (QTBUG-54732)
         for (const QQuickItemPrivate::ChangeListener &listener : listeners) {
             if (listener.types & QQuickItemPrivate::Geometry) {
                 if (change.matches(listener.gTypes))
-                    listener.listener->itemGeometryChanged(this, change, diff);
+                    listener.listener->itemGeometryChanged(this, change, oldGeometry);
             }
         }
     }
diff --git a/src/quick/items/qquickitemchangelistener_p.h b/src/quick/items/qquickitemchangelistener_p.h
index 19ff73056b..83c69a9330 100644
--- a/src/quick/items/qquickitemchangelistener_p.h
+++ b/src/quick/items/qquickitemchangelistener_p.h
@@ -115,12 +115,14 @@ private:
     int kind;
 };
 
+#define QT_QUICK_NEW_GEOMETRY_CHANGED_HANDLING
+
 class QQuickItemChangeListener
 {
 public:
     virtual ~QQuickItemChangeListener() {}
 
-    virtual void itemGeometryChanged(QQuickItem *, QQuickGeometryChange, const QRectF & /* diff */) {}
+    virtual void itemGeometryChanged(QQuickItem *, QQuickGeometryChange, const QRectF & /* oldGeometry */) {}
     virtual void itemSiblingOrderChanged(QQuickItem *) {}
     virtual void itemVisibilityChanged(QQuickItem *) {}
     virtual void itemOpacityChanged(QQuickItem *) {}
diff --git a/src/quick/items/qquickitemview.cpp b/src/quick/items/qquickitemview.cpp
index e017d6564a..7f8b26f20b 100644
--- a/src/quick/items/qquickitemview.cpp
+++ b/src/quick/items/qquickitemview.cpp
@@ -1206,10 +1206,10 @@ void QQuickItemViewPrivate::showVisibleItems() const
 }
 
 void QQuickItemViewPrivate::itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change,
-                                                const QRectF &diff)
+                                                const QRectF &oldGeometry)
 {
     Q_Q(QQuickItemView);
-    QQuickFlickablePrivate::itemGeometryChanged(item, change, diff);
+    QQuickFlickablePrivate::itemGeometryChanged(item, change, oldGeometry);
     if (!q->isComponentComplete())
         return;
 
diff --git a/src/quick/items/qquicklistview.cpp b/src/quick/items/qquicklistview.cpp
index 30625c7ea8..f89a995e76 100644
--- a/src/quick/items/qquicklistview.cpp
+++ b/src/quick/items/qquicklistview.cpp
@@ -131,7 +131,7 @@ public:
 
     void updateAverage();
 
-    void itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change, const QRectF &diff) Q_DECL_OVERRIDE;
+    void itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change, const QRectF &oldGeometry) Q_DECL_OVERRIDE;
     void fixupPosition() Q_DECL_OVERRIDE;
     void fixup(AxisData &data, qreal minExtent, qreal maxExtent) Q_DECL_OVERRIDE;
     bool flick(QQuickItemViewPrivate::AxisData &data, qreal minExtent, qreal maxExtent, qreal vSize,
@@ -1401,11 +1401,11 @@ bool QQuickListViewPrivate::hasStickyFooter() const
 }
 
 void QQuickListViewPrivate::itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change,
-                                                const QRectF &diff)
+                                                const QRectF &oldGeometry)
 {
     Q_Q(QQuickListView);
 
-    QQuickItemViewPrivate::itemGeometryChanged(item, change, diff);
+    QQuickItemViewPrivate::itemGeometryChanged(item, change, oldGeometry);
     if (!q->isComponentComplete())
         return;
 
@@ -1426,24 +1426,22 @@ void QQuickListViewPrivate::itemGeometryChanged(QQuickItem *item, QQuickGeometry
             // position all subsequent items
             if (visibleItems.count() && item == visibleItems.constFirst()->item) {
                 FxListItemSG *listItem = static_cast<FxListItemSG*>(visibleItems.constFirst());
-                const QRectF oldGeometry(item->x() - diff.x(),
-                                         item->y() - diff.y(),
-                                         item->width() - diff.width(),
-                                         item->height() - diff.height());
                 if (listItem->transitionScheduledOrRunning())
                     return;
                 if (orient == QQuickListView::Vertical) {
                     const qreal oldItemEndPosition = verticalLayoutDirection == QQuickItemView::BottomToTop ? -oldGeometry.y() : oldGeometry.y() + oldGeometry.height();
+                    const qreal heightDiff = item->height() - oldGeometry.height();
                     if (verticalLayoutDirection == QQuickListView::TopToBottom && oldItemEndPosition < q->contentY())
-                        listItem->setPosition(listItem->position() - diff.height(), true);
+                        listItem->setPosition(listItem->position() - heightDiff, true);
                     else if (verticalLayoutDirection == QQuickListView::BottomToTop && oldItemEndPosition > q->contentY())
-                        listItem->setPosition(listItem->position() + diff.height(), true);
+                        listItem->setPosition(listItem->position() + heightDiff, true);
                 } else {
                     const qreal oldItemEndPosition = q->effectiveLayoutDirection() == Qt::RightToLeft ? -oldGeometry.x() : oldGeometry.x() + oldGeometry.width();
+                    const qreal widthDiff = item->width() - oldGeometry.width();
                     if (q->effectiveLayoutDirection() == Qt::LeftToRight && oldItemEndPosition < q->contentX())
-                        listItem->setPosition(listItem->position() - diff.width(), true);
+                        listItem->setPosition(listItem->position() - widthDiff, true);
                     else if (q->effectiveLayoutDirection() == Qt::RightToLeft && oldItemEndPosition > q->contentX())
-                        listItem->setPosition(listItem->position() + diff.width(), true);
+                        listItem->setPosition(listItem->position() + widthDiff, true);
                 }
             }
             forceLayoutPolish();
diff --git a/src/quick/items/qquickloader.cpp b/src/quick/items/qquickloader.cpp
index 9aea9c50df..eeec562e3c 100644
--- a/src/quick/items/qquickloader.cpp
+++ b/src/quick/items/qquickloader.cpp
@@ -65,12 +65,12 @@ QQuickLoaderPrivate::~QQuickLoaderPrivate()
     disposeInitialPropertyValues();
 }
 
-void QQuickLoaderPrivate::itemGeometryChanged(QQuickItem *resizeItem, QQuickGeometryChange change
-                                              , const QRectF &diff)
+void QQuickLoaderPrivate::itemGeometryChanged(QQuickItem *resizeItem, QQuickGeometryChange change,
+                                              const QRectF &oldGeometry)
 {
     if (resizeItem == item)
         _q_updateSize(false);
-    QQuickItemChangeListener::itemGeometryChanged(resizeItem, change, diff);
+    QQuickItemChangeListener::itemGeometryChanged(resizeItem, change, oldGeometry);
 }
 
 void QQuickLoaderPrivate::itemImplicitWidthChanged(QQuickItem *)
diff --git a/src/quick/items/qquickloader_p_p.h b/src/quick/items/qquickloader_p_p.h
index fcccbfe4f5..a1e97b97d8 100644
--- a/src/quick/items/qquickloader_p_p.h
+++ b/src/quick/items/qquickloader_p_p.h
@@ -84,7 +84,7 @@ public:
     QQuickLoaderPrivate();
     ~QQuickLoaderPrivate();
 
-    void itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change, const QRectF &diff) Q_DECL_OVERRIDE;
+    void itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change, const QRectF &oldGeometry) Q_DECL_OVERRIDE;
     void itemImplicitWidthChanged(QQuickItem *) Q_DECL_OVERRIDE;
     void itemImplicitHeightChanged(QQuickItem *) Q_DECL_OVERRIDE;
     void clear();
diff --git a/src/quick/items/qquickview.cpp b/src/quick/items/qquickview.cpp
index a167f01484..573440ff7f 100644
--- a/src/quick/items/qquickview.cpp
+++ b/src/quick/items/qquickview.cpp
@@ -111,14 +111,14 @@ void QQuickViewPrivate::execute()
 }
 
 void QQuickViewPrivate::itemGeometryChanged(QQuickItem *resizeItem, QQuickGeometryChange change,
-                                            const QRectF &diff)
+                                            const QRectF &oldGeometry)
 {
     Q_Q(QQuickView);
     if (resizeItem == root && resizeMode == QQuickView::SizeViewToRootObject) {
         // wait for both width and height to be changed
         resizetimer.start(0,q);
     }
-    QQuickItemChangeListener::itemGeometryChanged(resizeItem, change, diff);
+    QQuickItemChangeListener::itemGeometryChanged(resizeItem, change, oldGeometry);
 }
 
 /*!
diff --git a/src/quickwidgets/qquickwidget.cpp b/src/quickwidgets/qquickwidget.cpp
index de3692afb0..1d617f5098 100644
--- a/src/quickwidgets/qquickwidget.cpp
+++ b/src/quickwidgets/qquickwidget.cpp
@@ -245,14 +245,14 @@ void QQuickWidgetPrivate::execute()
 }
 
 void QQuickWidgetPrivate::itemGeometryChanged(QQuickItem *resizeItem, QQuickGeometryChange change,
-                                              const QRectF &diff)
+                                              const QRectF &oldGeometry)
 {
     Q_Q(QQuickWidget);
     if (resizeItem == root && resizeMode == QQuickWidget::SizeViewToRootObject) {
         // wait for both width and height to be changed
         resizetimer.start(0,q);
     }
-    QQuickItemChangeListener::itemGeometryChanged(resizeItem, change, diff);
+    QQuickItemChangeListener::itemGeometryChanged(resizeItem, change, oldGeometry);
 }
 
 void QQuickWidgetPrivate::render(bool needsSync)
diff --git a/src/quickwidgets/qquickwidget_p.h b/src/quickwidgets/qquickwidget_p.h
index 3d64981797..0ba86172e6 100644
--- a/src/quickwidgets/qquickwidget_p.h
+++ b/src/quickwidgets/qquickwidget_p.h
@@ -87,7 +87,7 @@ public:
     ~QQuickWidgetPrivate();
 
     void execute();
-    void itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change, const QRectF &diff) Q_DECL_OVERRIDE;
+    void itemGeometryChanged(QQuickItem *item, QQuickGeometryChange change, const QRectF &oldGeometry) Q_DECL_OVERRIDE;
     void initResize();
     void updateSize();
     void updatePosition();