Qt绘图paint抗锯齿

void paintEvent(QPaintEvent *event) override
{
    QPainter painter(this);
    painter.drawEllipse(QPoint(100, 100), 50, 50);
    //设置抗锯齿 效率较低
    painter.setRenderHint(QPainter::Antialiasing);
    painter.drawEllipse(QPoint(200, 100), 50, 50);
}