Graphics View Queries

[linuxdev]

Hi,

Trying to understand the basics of Graphics View,
I have written a simple code snippet to do so,

int main(int argc, char *argv[])
{
    qDebug("In Main");
    QApplication a(argc, argv);
 
    QGraphicsScene *scene = new QGraphicsScene();
 
    QGraphicsView *viewGv = new QGraphicsView();
    viewGv->setScene(scene);
 
    scene->setSceneRect(QRectF(0, 0 , 10, 10));
    QGraphicsTextItem * item1 = scene->addText("Hello World");
 
    scene->setBackgroundBrush(Qt::blue);
    QPen pen1;
    pen1.setColor(Qt::red);
    scene->addLine(0,0, 10,10,  pen1);
 
    viewGv->show();
    return a.exec();
 
}

int main(int argc, char *argv[])
{
    qDebug("In Main");
    QApplication a(argc, argv);

    QGraphicsScene *scene = new QGraphicsScene();

    QGraphicsView *viewGv = new QGraphicsView();
    viewGv->setScene(scene);

    scene->setSceneRect(QRectF(0, 0 , 10, 10));
    QGraphicsTextItem * item1 = scene->addText("Hello World");

    scene->setBackgroundBrush(Qt::blue);
    QPen pen1;
    pen1.setColor(Qt::red);
    scene->addLine(0,0, 10,10,  pen1);

    viewGv->show();
    return a.exec();

}

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Here i have set the scene rect as (0,0,10,10), and have set its background to blue color.
When i run the application a small window appears as intended when i maximise it the entire window is filled with blue color....

I expected only the area (0,0,10,10) which represents the scene to be filled as blue..
whats happening here can anyone help me understand this???