QGraphicsView coordinates transformation

[marcel]

I think the best example is the Qt Demo application.
Take a look at this:

void MainWindow::resizeEvent(QResizeEvent *event)
{
    this->resetMatrix();
    this->scale(event->size().width() / 800.0, event->size().height() / 600.0);
    QGraphicsView::resizeEvent(event);
    DemoItem::setMatrix(this->matrix());
 
    if (this->trolltechLogo){
        const QRectF r = this->scene->sceneRect();
        QRectF ttb = this->trolltechLogo->boundingRect();
        this->trolltechLogo->setPos(int((r.width() - ttb.width()) / 2), 595 - ttb.height());
        QRectF qtb = this->qtLogo->boundingRect();
        this->qtLogo->setPos(802 - qtb.width(), 0);
    }
 
    // Changing size will almost always
    // hurt FPS during the changing. So
    // ignore it.
    this->fpsHistory.clear();
}

void MainWindow::resizeEvent(QResizeEvent *event)
{
    this->resetMatrix();
    this->scale(event->size().width() / 800.0, event->size().height() / 600.0);
    QGraphicsView::resizeEvent(event);
    DemoItem::setMatrix(this->matrix());

    if (this->trolltechLogo){
        const QRectF r = this->scene->sceneRect();
        QRectF ttb = this->trolltechLogo->boundingRect();
        this->trolltechLogo->setPos(int((r.width() - ttb.width()) / 2), 595 - ttb.height());
        QRectF qtb = this->qtLogo->boundingRect();
        this->qtLogo->setPos(802 - qtb.width(), 0);
    }
    
    // Changing size will almost always
    // hurt FPS during the changing. So
    // ignore it.
    this->fpsHistory.clear();
}

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This is the resize event of the main window, which is also a QGraphicsView.
The first 3 lines are the most relevant.

Regards