change qgraphicsitem position by scene resize - c++

Question

I want to change my QGraphicsItem position by resize event over graphicsview.
I scaled position by newSize/oldSize but my items stay at the same position.
I don't know what wrong with my code or a better way to change my items position.
bool cameraItems::eventFilter(QObject *obj, QEvent *event)
{
if (event->type() == QEvent::Resize) {
QResizeEvent *e = static_cast<QResizeEvent*>(event);
if(obj == ui->graphicsView) {
setFixedSizeForGraphicsView(e->size(), e->oldSize());
ui->graphicsView->scene()->setSceneRect(0, 0, e->size().width(), e->size().height());
ui->graphicsView->setSceneRect(0, 0, e->size().width(), e-->size().height());
}
}
QWidget::eventFilter(obj, event);
}
void cameraItems::setFixedSizeForGraphicsView(QSize size, QSize oldSize)
{
foreach (singleCamera *cam, m_cameras) {
prevImageSize = cam->imageSize();
QPointF ppos = cam->pos();
QPointF newPos = QPointF((ppos.x()/prevSize.width())*size.width(), (ppos.y()/prevSize.height())*size.height());
cam->setPos(newPos);
}
}

Answer 1

You can make your custom class which inherits from QGraphicsView and then reimplement resizeEvent( QResizeEvent *event ) like:
void MyView::resizeEvent(QResizeEvent *event)
{
QRectF rect = this->scene()->itemsBoundingRect();
fitInView(rect, ,Qt::KeepAspectRatio);
QGraphicsView::resizeEvent(event);
}
This way the view will always display the whole scene. I.e. if the window size is changed and the graphicsView is resized, The scene gets scaled and you can see everything appropriately.