Qt将图片绘制成圆形

QPixmap roundedPixmap(const QPixmap& src, QSize size, int radius) {
    QPixmap scaled = src.scaled(size, Qt::KeepAspectRatioByExpanding, Qt::SmoothTransformation);
    QPixmap dest(size);
    dest.fill(Qt::transparent);

    QPainter painter(&dest);
    painter.setRenderHint(QPainter::Antialiasing);
    QPainterPath path;
    path.addRoundedRect(0, 0, size.width(), size.height(), radius, radius);
    painter.setClipPath(path);
    painter.drawPixmap(0, 0, scaled);

    return dest;
}

QPixmap rounded = roundedPixmap(QPixmap("xxx.jpg"), ui->portrait_label->size(), 20); // 设置圆角半径

ui->portrait_label->setPixmap(rounded);