Graphics View控件有几种显示Pixmap的方式？请分别给出示例代码

Graphics View控件有两种显示Pixmap的方式：
1. 使用QPixmapItem将QPixmap添加到场景中
示例代码：

QGraphicsScene *scene = new QGraphicsScene();
QPixmap pixmap("image.jpg");
QGraphicsPixmapItem *pixmapItem = new QGraphicsPixmapItem(pixmap);
scene->addItem(pixmapItem);
QGraphicsView *view = new QGraphicsView(scene);
view->show();

2. 自定义GraphicsItem，重写paint函数，在其中绘制QPixmap
示例代码：

class PixmapItem : public QGraphicsItem {
public:
    PixmapItem(const QPixmap &pixmap) : pixmap(pixmap) {}
    QRectF boundingRect() const override { return QRectF(); }
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget) override {
        painter->drawPixmap(QPointF(0, 0), pixmap);
    }
private:
    QPixmap pixmap;
};

QGraphicsScene *scene = new QGraphicsScene();
QPixmap pixmap("image.jpg");
PixmapItem *pixmapItem = new PixmapItem(pixmap);
scene->addItem(pixmapItem);
QGraphicsView *view = new QGraphicsView(scene);
view->show();

笑话时间：为什么猪不能练字？因为它们都是丑的！