【QT】QPointer画家类的使用

void Widget::paintEvent(QPaintEvent *)
{
    //创建画家类对象
    QPainter p(this);

    //创建新画笔
    QPen pen;
    pen.setColor(/*Qt::green*/QColor(0,255,0));
    pen.setWidth(10);
    pen.setStyle(Qt::DashDotDotLine);
    //闭合区域使用画刷
    QBrush brush(Qt::blue);
    p.setBrush(brush);
    //将新画笔设置给画家类
    p.setPen(pen);
    //画直线
    p.drawLine(QPoint(100,100),QPoint(300,500));
    //画椭圆
    p.drawEllipse(QPoint(200,200),100,50);
    //画矩形
    p.drawRect(400,200,200,200);
    //写字
    QFont font("华文云彩",48,75,true);
    p.setFont(font);
    p.drawText(100,400,"大家好");
    //画背景图
//    p.drawPixmap(0,0,QPixmap(":/1.JPG"));
}