qwidget添加阴影效果

    QGraphicsDropShadowEffect *shadow_effect = new QGraphicsDropShadowEffect(this);
    shadow_effect->setOffset(0, 0);
    shadow_effect->setColor(QColor(43, 43, 43));
    shadow_effect->setBlurRadius(8);
    ui->label->setGraphicsEffect(shadow_effect);