x[0] = 10;
y[0] = 50;

x_offset = 0.7;
y_offset = 1.0;
QCPItemText *textLabel = new QCPItemText(ui->widget);
textLabel->position->setCoords(x[0]- x_offset, y[0] + y_offset); // place position at center/top of axis rect
QString str;
str.sprintf("%d", 10);

textLabel->setFont(QFont(font().family(), 8)); // make font a bit larger

The problem is , if x-axis range is (-20,20), y-axis range is (-50,100), the text lable is near the point(x[0],y[0]) properly. when x-axis range is set to (-200,200), y-axis range is set to (-500,500), the lable is merge with point(x[0],y[0]) because of large scale, what I want is lable's postion is near the point from the eye of view

how to solve this problem? for this kind of problem,MATLAB solved it perfectly, point and its lable are
displayed rightly under different scale x-axis and y-axis