Qwt Tex Text Doesnt work for me

[gbmtoday]

Hey guys

I want to use qwt for rendering tex texts , but it doesnt work properly .

QPainter * painter = new QPainter (this);
QRect rect = QRect (0 , 0 , 400 , 200);
qtext = new QwtText ("\sqrt{\pi}",QwtText::TeXText);
qtext->draw(painter,rect);

QPainter * painter = new QPainter (this);
QRect rect = QRect (0 , 0 , 400 , 200);
qtext = new QwtText ("\sqrt{\pi}",QwtText::TeXText);
qtext->draw(painter,rect);

To copy to clipboard, switch view to plain text mode 

But i just shows the original text and doesnt transform it to math symbols .

Anybody has an idea ?!

Thank u 4 your time.