qt 生成圆角三角形

QImage img(220, 220, QImage::Format_ARGB32);
    img.fill(0);

    QPainter painter(&img);
    painter.setRenderHints(QPainter::Antialiasing, true);
    painter.setRenderHints(QPainter::SmoothPixmapTransform , true);

    QPen pen;
    int penWidth = 20;
    pen.setWidth(penWidth);
    pen.setJoinStyle(Qt::RoundJoin);
    pen.setColor(Qt::green);
    painter.setPen(pen);


    int di = (200-penWidth)/2;
    int height = (180-penWidth)/2;

    QPoint center = img.rect().center();
    static const QPointF points[3] = {
        QPointF(center.x(), center.y()+height),
        QPointF(center.x()-di, center.y()-height),
        QPointF(center.x()+di, center.y()-height)
    };
    painter.drawConvexPolygon(points, 3);

    QPen oldPen = painter.pen();
    oldPen.setWidth(18);
    painter.setPen(oldPen);

    static const QPointF linepoints[2] = {
        QPointF(center.x(), center.y()-height + penWidth/2 +18),
        QPointF(center.x(), center.y()-height + penWidth/2 +18+50)
    };
    painter.drawConvexPolygon(linepoints, 2);
    painter.setBrush(Qt::green);
    painter.setPen(Qt::NoPen);
    int EllipseR = 20;
    painter.drawEllipse(center.x()-EllipseR/2, center.y()-height + penWidth/2 +18+50+26-EllipseR/2, EllipseR, EllipseR);

    img.save("test.png");

参考文献：CSS 奇思妙想 | 巧妙的实现带圆角的三角形 - 腾讯云开发者社区-腾讯云 (tencent.com)