我要在一个toolbutton 上画一个简单多边形图：程序如下
previous = new QToolButton(this);
QImage fixedImage (resultSize, QImage::Format_ARGB32_Premultiplied);
QPainter painter(&fixedImage);
painter.setPen(QPen(Qt::blue, 0));
painter.setBrush(QBrush(Qt::blue, Qt::SolidPattern));
painter.setRenderHint(QPainter::Antialiasing, true);
painter.fillRect(fixedImage.rect(), Qt::transparent);
painter.drawPolygon(points,9);
painter.end();
previous->setIcon(QPixmap::fromImage(fixedImage));
但是程序运行时图看不到，请帮忙看看，
