QGraphicsScene на разных формах

void CameraView::paint(QPainter *painter, const QStyleOptionGraphicsItem *, QWidget *)
{
    if (!painter) {
        qDebug() << "painter is NULL";
        return;
    }
    if (m_mutex.tryLock(500)) {
        try {
            qreal x = (m_size.width() - m_image.width()) / 2.0;
            qreal y = (m_size.height() - m_image.height()) / 2.0;
 
            QRect rect;
            rect.setSize(m_size);
            rect.setTopLeft(QPoint(0, 0));
 
            //painter->fillRect(rect, Qt::black);
            painter->drawImage(x, y, m_image);
            //if (m_borderPen.color().alpha() != 0) {
                painter->setPen(m_borderPen);
                painter->drawRect(rect);
            //}
/*
            QPen pen;
            pen.setWidth(1);
            pen.setColor(Qt::blue);
            painter->setFont(m_font);
            painter->setPen(pen);
            painter->drawText(5, m_size.height() - 5, m_text);
*/
        } catch (QException e) {
            debugMsg("exception while paint cameraView: " + QString(e.what()));
        } catch (...) {
            debugMsg("exception while paint cameraView");
        }
 
        m_mutex.unlock();
    }
}

class CameraView : public QGraphicsItem