Hi,
I am generating a FACS plot, which is simply a large number of points, each a QwtPlotMarker:

for (i=0; i<Global::nFACS_cells; i++) {
x = Global::FACS_data[Global::nvars_used*i+kvar_x];
y = Global::FACS_data[Global::nvars_used*i+kvar_y];
x = xscale*x;
y = yscale*y;
y = max(y,1.01*ymin);
if (x >= xmin) {
QwtPlotMarker* m = new QwtPlotMarker();
m->setSymbol( symbol );
m->setValue( QPointF( x,y ) );
m->attach( qpFACS );
}
}

when nFACS_cells = 80k this is taking 35 seconds (Qwt 5.2.1, Windows 7, Core i7).
Is there something I can do to speed this up? I don't want to go to a later Qwt version unless absolutely necessary.

Thanks
Gib