QCustomPlot Discussion and Comments

I would like to use this function to paint on PDF,

void QCustomPlot::toPainter (QCPPainter * painter, int width = 0, int height = 0)

But I want to paint it on the specific position with the start position x and y,
cause I have some infomation on the top of PDF, so I want to move it down.
So how can I do it?

I just found QPainter has a function translatecan solve it.
Maybe I should read the doc first.