Freehand painting with gradient brush

[olidem]

Hi!

I derived from QGraphicsItem and I would like to be able to perfom some freehand painting.

For normal pens, this is not a problem, I manage a QImage and in my mouseReleaseEvent, I draw lines from one to the next event position:

void GraphicsHairstyleItem::mouseReleaseEvent(QGraphicsSceneMouseEvent * event)
{
    QPainter p( &backgroundImage );
    QPen pen;
    pen.setWidth(30);
    pen.setColor(Qt::red);
    p.setPen(pen);
    p.drawLine(event->lastPos(),event->pos());
    p.end();
}

void GraphicsHairstyleItem::mouseReleaseEvent(QGraphicsSceneMouseEvent * event)
{
    QPainter p( &backgroundImage );
    QPen pen;
    pen.setWidth(30);
    pen.setColor(Qt::red);
    p.setPen(pen);
    p.drawLine(event->lastPos(),event->pos());
    p.end();
}

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The question now is:

How can I use a pen which is "diffuse" at the boundary, ie. a radial gradient whose alpha-component goes to 0 at the outside ???

I know that I could get a QRadial Gradient as QBrush like

QRadialGradient gradient(15, 15, 15, 15, 15);
gradient.setColorAt(0, QColor::fromRgbF(1, 1, 1, 1));
gradient.setColorAt(1, QColor::fromRgbF(1, 1, 1, 0));
QBrush b(gradient);

QRadialGradient gradient(15, 15, 15, 15, 15);
gradient.setColorAt(0, QColor::fromRgbF(1, 1, 1, 1));
gradient.setColorAt(1, QColor::fromRgbF(1, 1, 1, 0));
QBrush b(gradient);

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this does not work and as far as I know, brushes are used for filling, not for the outlines.

Appreciate any help!

Thanks a lot!!!

Olli