resizeEvent - resizing unproportionally

[Lykurg]

The code does not help much. We need to see how you make your drawing. But before: Your widget stays a square or your drawing?

to determine you can use:

void WykresSlupkowy::paintEvent(QPaintEvent *event)
{
paintMyWidget();
QWidget::paintEvent(event);
QPainter p(this);
p.setPen(QPen(Qt::red, 1));
p.drawRect(rect().adjusted(0, 0, -1, -1));
}

void WykresSlupkowy::paintEvent(QPaintEvent *event)
{
paintMyWidget();
QWidget::paintEvent(event);
QPainter p(this);
p.setPen(QPen(Qt::red, 1));
p.drawRect(rect().adjusted(0, 0, -1, -1));
}

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So is the red border always a square?