Height of the text without balnk space at the top

[THRESHE]

Hello everyone
I need to center text in a rectangle and I use QFontMetrics::height() to know the height of it.
But it doesn't return me the height but instead it gives me blank space at the top

QPainter painter(this);
painter.setPen(QPen(QColor(Qt::black)));
QFont font = QFont("Times", 50, QFont::Normal);
painter.setFont(font);
QFontMetrics metrics(font);
 
int heightOfText  = metrics.height();
painter.drawLine(0, 200 - heightOfText,
						1000, 200 - heightOfText);
painter.drawLine(0, 200, 1000, 200);
painter.drawText(0, 200, "Gradient Text");

QPainter painter(this);
painter.setPen(QPen(QColor(Qt::black)));
QFont font = QFont("Times", 50, QFont::Normal);
painter.setFont(font);
QFontMetrics metrics(font);

int heightOfText  = metrics.height();
painter.drawLine(0, 200 - heightOfText,
						1000, 200 - heightOfText);
painter.drawLine(0, 200, 1000, 200);
painter.drawText(0, 200, "Gradient Text");

To copy to clipboard, switch view to plain text mode 

This code gives me the result displayed on the screenshot below
So My question is how to find text height without that blank space ?
(I suppose it has something with ascent and descent...)