automatic resize using qgraphicsview with qgraphicsscene and qopenglwidget - qt

Question

I'm trying to use QGraphicsView with QOpenGLWidget in a MainWindow:
Exactly:
My QMainWindow contains a few layouts and widget. Also a QGraphicsView (class graphicsView inherits from QGraphicsView).
In a "second" step i create a QGraphicsScene and add a openglwidget (class OpenGLControl inherits from QOpenGLWidget). In OpenGLControl I only set the backround for testing my application (glClearColor ...).
Now my request, when I change the size of mainWindow, i want to change the size of QGraphicsView, QGraphicsScene and QOpenGLWidget, too. I try a resizeEvent in graphicsView, but it didn't work.
Implementation of mainwindow (.cpp):
#include "mainwindow.h"
#include "openglcontrol.h"
#include "graphicsview.h"
MainWindow::MainWindow(QWidget *parent)
: QMainWindow(parent)
{
createLayout();
createScene();
}
void MainWindow::createLayout()
{
view = new graphicsView;
kosGrid = new QGridLayout;
xKoord = new QLineEdit;
yKoord = new QLineEdit;
zKoord = new QLineEdit;
drawButton = new QPushButton("Draw Point");
clearButton = new QPushButton("Clear");
KoordLabel = new QLabel("Koordinaten");
xLabel = new QLabel("X:");
yLabel = new QLabel("Y: ");
zLabel = new QLabel("Z: ");
controlBox = new QVBoxLayout;
controlBox->addStretch(1);
controlBox->addWidget(KoordLabel);
xhBox = new QHBoxLayout;
xhBox->addWidget(xLabel);
xhBox->addWidget(xKoord);
controlBox->addLayout(xhBox);
yhBox = new QHBoxLayout;
yhBox->addWidget(yLabel);
yhBox->addWidget(yKoord);
controlBox->addLayout(yhBox);
zhBox = new QHBoxLayout;
zhBox->addWidget(zLabel);
zhBox->addWidget(zKoord);
controlBox->addLayout(zhBox);
controlBox->addWidget(drawButton);
controlBox->addWidget(clearButton);
xKoord->setFixedWidth(50);
yKoord->setFixedWidth(50);
zKoord->setFixedWidth(50);
drawButton->setSizePolicy(QSizePolicy::Fixed,QSizePolicy::Fixed);
xKoord->setSizePolicy(QSizePolicy::Fixed,QSizePolicy::Fixed);
yKoord->setSizePolicy(QSizePolicy::Fixed,QSizePolicy::Fixed);
zKoord->setSizePolicy(QSizePolicy::Fixed,QSizePolicy::Fixed);
hBox = new QHBoxLayout;
hBox->addLayout(controlBox);
hBox->addWidget(view);
mainLayout = new QWidget;
mainLayout->setLayout(hBox);
setCentralWidget(mainLayout);
}
void MainWindow::createScene()
{
scene = new QGraphicsScene(this);
qsurface = new QSurfaceFormat;
qsurface->setRenderableType(QSurfaceFormat::OpenGL);
qsurface->setProfile(QSurfaceFormat::CoreProfile);
qsurface->setVersion(3,3);
oglwidget = new OpenGLControl;
oglwidget->setFormat(*qsurface);
oglwidget->
//oglwidget->resize(10,10);
scene->addWidget(oglwidget);
view->setScene(scene);
}
and my attempt for the resizeEvent:
void graphicsView::resizeEvent(QResizeEvent *event)
{
if(scene())
scene()->setSceneRect(QRect(QPoint(0,0), event->size()));
QGraphicsView::resizeEvent(event);
}
at last a screenshot of the (resized) mainWindow (the QOpenGLWidget (blue background) is smaller than the QGraphicsView)
mainWindow with QOpenGLWidget
Is there a SIGNAL I can use ? Or can anybody help me on another way ?
Thank You