int main(int argc,char* argv[ ])

{

    QApplication app(argc,argv);

    //新建场景

    QGraphicsScene scene;

    //创建矩形图形项

QTransform transform;　　  //QT5添加

    transform.rotate(+0.0);//QT5添加

    QGraphicsRectItem *item = new QGraphicsRectItem(0, 0, 100, 100);

    //将图形项添加到场景中

    scene.addItem(item);

    //输出(50, 50)点处的图形项

qDebug() << scene.itemAt(50, 50,transform);  //  QT5添加 transform

    //为场景创建视图

    QGraphicsView view(&scene);

    //设置场景的前景色

    view.setForegroundBrush(QColor(255, 255, 255, 100));

    //设置场景的背景图片

    view.setBackgroundBrush(QPixmap("../myScene/background.png"));

    view.resize(400, 300);

    view.show();

    return app.exec();

}
qt4中函数QGraphicsItem *QGraphicsScene::itemAt(qreal x, qreal y)
qt5中函数发生了变化

QGraphicsItem *QGraphicsScene::itemAt(qreal x, qreal y, const QTransform &deviceTransform) const

This is an overloaded function.

Returns the topmost visible item at the position specified by (x, y), or 0 if there are no items at this position.

deviceTransform is the transformation that applies to the view, and needs to be provided if the scene contains items that ignore transformations.

This convenience function is equivalent to calling itemAt(QPointF(x, y), deviceTransform).

Note: See items() for a definition of which items are considered visible by this function.

This function was introduced in Qt 4.6.

QT5中运行QT4场景程序 QGraphicsItem *QGraphicsScene::itemAt 函数报错的解决