How to print a widget to PDF only with the minimal content?

I print a widget (a tab from a QTabWidget) with its content with this code :

void MainWindow::print()
{
    quint8 tabIndex = quint8(ui->tabWidget->currentIndex());
    CharacterSheetWidget* widget = dynamic_cast< CharacterSheetWidget* >( ui->tabWidget->widget(tabIndex) );
    QString filePath = QFileDialog::getSaveFileName(this, QString(tr("Print as PDF...")), QString(), "PDF file (*.pdf)");

    if(filePath.isEmpty())
        return;

    QPrinter printer;
    printer.setOutputFormat(QPrinter::PdfFormat);
    printer.setOutputFileName(filePath);
    printer.setPaperSize(QPrinter::A4);
    printer.setResolution(300);
    printer.setFullPage(false);
    printer.setPageMargins(5, 5, 5, 5, QPrinter::Millimeter);

    QString originalStyle = widget->styleSheet();
    widget->setStyleSheet("background-color:white;");

    QPainter painter;
    painter.begin(&printer);
    double xscale = printer.pageRect().width() / double(widget->width());
    double yscale = printer.pageRect().height() / double(widget->height());
    double scale = qMin(xscale, yscale);
    painter.translate(printer.paperRect().center());
    painter.scale(scale, scale);
    painter.translate(- widget->width()/ 2, - widget->height()/ 2);
    painter.setRenderHint(QPainter::Antialiasing, true);
    painter.setRenderHint(QPainter::SmoothPixmapTransform, true);
    widget->render(&painter);
    painter.end();
    widget->setStyleSheet(originalStyle);
}

but it prints it with a lot of space on the right and on the bottom. I would like to print it with the minimal content area.

For example on this image, you see that it prints the red area in the pdf, I would like it prints the blue area.

How should I do (if you need more information, please tell me) ?

By the way, I founded a solution : Before "QPainter painter;", I added this code :

QSize minSize = widget->minimumSizeHint();
int minWidth = minSize.width();
int minHeight = minSize.height();

And replaced all widget->width() and widget->height by minWidth and minHeight.