Paint to pixmap directly

Currently I create an QImage first and pass that to a pixmap. This is done with this code:

Code:

QImage QRgbMatrix::toImage()
{
    QImage image = QImage(m_size_x, m_size_y, QImage::Format_RGB32);
 
    int r, g, b;     r = g = b = 0;
    for ( int y = 0; y < m_size_y; y++ )
    {
        QRgb *line = (QRgb *)image.scanLine(y) ;
        for ( int x = 0; x < m_size_x; x++ )
        {
            int pos = ArrPos(x,y);
 
            r = d->red[pos];
            g = d->green[pos];
            b = d->blue[pos];
 
            *line++ = qRgb(r, g, b);
 
        }
    }
    return image;
}
 
QPixmap QRgbMatrix::toPixmap()
{
    return QPixmap::fromImage(toImage());
}

Now my question is, if it would be possible to create a pixmap image without creating an QImage first.
My main concern about the QImage step is the time required for the conversions.