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QGraphicsScene: prevent lots of detaching d/t editing of copies 

QTouchEvent::touchPoints() returns a const-&, but the old
code took a copy, over which it then iterated, modifying
the touch points, causing (necessary) detaches of both the
list and the touch points.

Befriend QTouchEvent and modify the list in-place, avoiding
all detaches in the likely case that QTouchPoint contains the
only copy of the touch point list.

This is all the more important as the function is called once
for every item-under-mouse in sendTouchBeginEvent().

Port to C++11 range-for as a drive-by.

Change-Id: I2f74d19845711d97e3566886123b5d18d55db74c
Reviewed-by: Andreas Aardal Hanssen <andreas@hanssen.name>
bb10
Marc Mutz 2015-12-21 11:14:29 +01:00
parent feea236d92
commit e3e0240c77
2 changed files with 4 additions and 4 deletions
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3
src/gui/kernel/qevent.h
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@ -908,6 +908,9 @@ protected:
friend class QGuiApplicationPrivate;
friend class QApplication;
friend class QApplicationPrivate;
#ifndef QT_NO_GRAPHICSVIEW
friend class QGraphicsScenePrivate; // direct access to _touchPoints
#endif
};
Q_DECLARE_TYPEINFO(QTouchEvent::TouchPoint, Q_MOVABLE_TYPE);
Q_DECLARE_OPERATORS_FOR_FLAGS(QTouchEvent::TouchPoint::InfoFlags)

5
src/widgets/graphicsview/qgraphicsscene.cpp
View File

@ -5834,14 +5834,11 @@ void QGraphicsScenePrivate::removeView(QGraphicsView *view)
void QGraphicsScenePrivate::updateTouchPointsForItem(QGraphicsItem *item, QTouchEvent *touchEvent)
{
QList<QTouchEvent::TouchPoint> touchPoints = touchEvent->touchPoints();
for (int i = 0; i < touchPoints.count(); ++i) {
QTouchEvent::TouchPoint &touchPoint = touchPoints[i];
for (auto &touchPoint : touchEvent->_touchPoints) {
touchPoint.setRect(item->mapFromScene(touchPoint.sceneRect()).boundingRect());
touchPoint.setStartPos(item->d_ptr->genericMapFromScene(touchPoint.startScenePos(), static_cast<QWidget *>(touchEvent->target())));
touchPoint.setLastPos(item->d_ptr->genericMapFromScene(touchPoint.lastScenePos(), static_cast<QWidget *>(touchEvent->target())));
}
touchEvent->setTouchPoints(touchPoints);
}
int QGraphicsScenePrivate::findClosestTouchPointId(const QPointF &scenePos)