Qt——painter类

widget.h:

#ifndef WIDGET_H

#define WIDGET_H

#include <QWidget>

#include<QPainter>

#include<QPaintEvent>

 

#include<QPaintDevice>

class Widget : public QWidget

{

    Q_OBJECT

public:

    Widget(QWidget *parent = 0);

    ~Widget();

protected:

    void paintEvent(QPaintEvent *);

};

#endif // WIDGET_H

 

 

 

widget.cpp:

#include "widget.h"

Widget::Widget(QWidget *parent)

    : QWidget(parent)

{

}

Widget::~Widget()

{

}

void Widget::paintEvent(QPaintEvent *)

{

    QPainter painter(this);

    painter.setPen(Qt::blue);

    painter.setFont(QFont("Arial",30));

    painter.drawText(rect(),Qt::AlignCenter,"Qt");

    painter.drawEllipse(QRect(0,0,width()-1,height()-1));

}