class Widget : public QWidget
{
    Q_OBJECT


protected:
    void    paintEvent(QPaintEvent *event) Q_DECL_OVERRIDE;

public:
    Widget(QWidget *parent = nullptr);
    ~Widget();

private:
    Ui::Widget *ui;
};


oid Widget::paintEvent(QPaintEvent *event)
{
   QPainter    painter(this);  //創(chuàng)建QPainter對象
   painter.setRenderHint(QPainter::Antialiasing);
   painter.setRenderHint(QPainter::TextAntialiasing);
   
   int W=this->width();    //繪圖區(qū)寬度
   int H=this->height();   //繪圖區(qū)高度
   QRect   rect(W/4,H/4,W/2,H/2);  //中間區(qū)域矩形框
   
   //設(shè)置畫筆
   QPen    pen;
   pen.setWidth(3);        //線寬
   pen.setColor(Qt::red);  //劃線顏色
   pen.setStyle(Qt::SolidLine);    //線的樣式，實(shí)線、虛線等
   pen.setCapStyle(Qt::FlatCap);   //線端點(diǎn)樣式
   pen.setJoinStyle(Qt::BevelJoin);    //線的連接點(diǎn)樣式
   painter.setPen(pen);
   
   //設(shè)置畫刷
   QBrush  brush;
   brush.setColor(Qt::yellow); //畫刷顏色
   brush.setStyle(Qt::SolidPattern); //畫刷填充樣式
   painter.setBrush(brush);
   
   //繪圖
   painter.drawRect(rect);     //填充定義的漸變區(qū)域
   
    event->accept();
}

   //設(shè)置畫刷
    QPixmap texturePixmap(":images/images/texture.jpg");
    QBrush  brush;
    brush.setStyle(Qt::TexturePattern);     //畫刷填充樣式
    brush.setTexture(texturePixmap);        //設(shè)置材質(zhì)圖片
    painter.setBrush(brush);