QT图片缩放

QLabel *label_3;
QSize size(501,591);
QPixmap pixmap1(":/irbg.bmp");
QPixmap pixmap(pixmap1.scaled(size)); //此处为缩放函数
label_3 = new QLabel(this);
label_3->setObjectName(QString::fromUtf8("label_3"));
label_3->setGeometry(QRect(0, 0, 501, 591));
// label_3->setPixmap(QPixmap(QString::fromUtf8(":/irbg.bmp")));
label_3->setPixmap(pixmap);