There is some problem drawing anti-aliasing text on windows platform(Linux is ok). The drawed text is antialiased only on some font sizes, ex. Arial 48 is drawed good(antialiased), while Arial 47 is aliased.

Here is code sample:

void Widget::paintEvent(QPaintEvent * event)
{
Q_UNUSED(event);

QPainter painter(this);

painter.setFont(m_font);

painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);

painter.drawText(10, 80, "Some text.");
}

where m_font can be set as:
m_font = QFont("Arial", 47, 25);
or
m_font = QFont("Arial", 48, 25);

I have attached small demo app that shows the problem, and printscreen of that app drawing text in Arial size 47, and size 48, in both Windows(with issue) and Linux(draws ok).