Circle with radial gradient

[RiseOfDeath]

hi. I want draw some circles with radial gradient, but is look like black circle.

@QRadialGradient gradient(0, 0, 50,0,0);
gradient.setColorAt(0, Qt::yellow);
gradient.setColorAt(1, Qt::black);
gradient.setSpread(QGradient::PadSpread);

QBrush brush(gradient);
brush.setStyle(Qt::RadialGradientPattern);
QPainter painter(this);

painter.setRenderHint(QPainter::Antialiasing);
painter.setBrush(brush);
painter.setPen(Qt::NoPen);


for(int i=0;i<points.size();i++)
{
    painter.drawEllipse(i*10, (points.at(i)*-1)+(this->height()/2),50,50);

}@

points is QList<float> and it not empty