#ifndef WIDGET_H
#define WIDGET_H
 
#include<math.h>
#include<QResizeEvent>
#include<QGroupBox>
#include<QTimer>
#include<QTime>
#include<QPainter>
 
#include <QWidget>
 
namespace Ui {
class Widget;
}
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    explicit Widget(QWidget *parent = 0);
    ~Widget();
protected:
    void paintEvent(QPaintEvent *event);
 
private:
    Ui::Widget *ui;
};
 
#endif // WIDGET_H

#include "widget.h"
#include "ui_widget.h"
 
Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    QTimer *timer = new QTimer(this);  //連接信號與槽
    connect(timer, SIGNAL(timeout()), this, SLOT(update()));
    timer->start(1000);
    //設置窗體名稱與大小
    setWindowTitle(tr("Clock"));
    ui->setupUi(this);
    resize(350,350);
}
 
Widget::~Widget()
{
    delete ui;
}
 
void Widget::paintEvent(QPaintEvent *event)
{
    static const QPoint hourHand[3] =
    {
        QPoint(5, 14),
        QPoint(-5, 14),
        QPoint(0, -50)
    };
    static const QPoint minuteHand[3] =
    {
        QPoint(5, 14),
        QPoint(-5,14),
        QPoint(0, -70)
    };
    static const QPoint secondHand[3] =
    {
        QPoint(5, 14),
        QPoint(-5, 14),
        QPoint(0, -80)
    };
    static const QPoint line_long[2]=
    {
        QPoint(0,100),
        QPoint(0,80)
    };
    static const QPoint line_short[2]={
        QPoint(0,100),
        QPoint(0,95)
    };
    //繪制的范圍
    int side = qMin(width(), height());
    //獲取當前的時間
    QTime time = QTime::currentTime();
    //聲明用來繪圖用的painter
    QPainter painter(this);
    //繪制的圖像反鋸齒
    painter.setRenderHint(QPainter::Antialiasing);
    //重新定位坐標起始點，把坐標原點放到窗體的中央
    painter.translate(width() / 2, height() / 2);
    //在表盤內添加文字（任意）
    //painter.drawText(-75,-120,100,170,Qt::AlignRight,tr("ROLEX"));
    //設定畫布的邊界
    painter.scale(side / 200.0, side / 200.0);
    //填充邊線設為黑色，也可以設置為NoPen
    painter.setPen( Qt::black );
    //畫刷顏色設定
    painter.setBrush(Qt::black);
    //保存painter的狀態
    painter.save();
    //設置painter的旋轉角度
    painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0)));
    //填充時針的區域
    painter.drawConvexPolygon(hourHand, 3);
    painter.restore();
    painter.setPen(Qt::black);
    //12個個刻度循環
    for (int i = 0; i < 12; ++i)
    {
        painter.drawLine(line_long[0],line_long[1]);
        painter.rotate(30.0);
    }
    //繪制分針轉角、刻度
    painter.setPen(Qt::black);
    painter.setBrush(Qt::black);
    painter.save();
    painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
    painter.drawConvexPolygon(minuteHand, 3);
    painter.restore();
    painter.setPen(Qt::black);
    for (int j = 0; j < 60; ++j)
    {
        if ((j % 5) != 0)
        painter.drawLine(line_short[0],line_short[1]);
        painter.rotate(6.0);
    }
 
     //繪制分針轉角、刻度
    painter.setPen(Qt::black);
    painter.setBrush(Qt::black);
    painter.save();
    painter.rotate(6.0 * (time.minute() + time.second() / 60.0));
    painter.drawConvexPolygon(minuteHand, 3);
    painter.restore();
    painter.setPen(Qt::black);
    for (int j = 0; j < 60; ++j)
    {
        if ((j % 5) != 0)
        painter.drawLine(line_short[0],line_short[1]);
        painter.rotate(6.0);
    }
   //繪制秒針轉角
    painter.setPen(Qt::black);
    painter.setBrush(Qt::black);
    painter.save();
    painter.rotate(6.0*time.second());
    painter.drawConvexPolygon(secondHand,3);
    painter.restore();
 
}

#include "widget.h"
#include <QApplication>
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    Widget w;
    w.show();
    return a.exec();
}