Qpainter画时钟

根据以下文章整理的时钟界面的代码

Qt浅谈之二：钟表(时分秒针)

http://blog.youkuaiyun.com/taiyang1987912/article/details/30272105

下面贴下整理后的代码

MainWindow::MainWindow(QWidget *parent) :

    QMainWindow(parent),

    ui(new Ui::MainWindow)

{

    ui->setupUi(this);

    m_updateTime = new QTimer(this);

    connect(m_updateTime,SIGNAL(timeout()),this,SLOT(update())); //每隔1s刷新一次界面

    m_updateTime->start(1000);

}

 

 

void MainWindow::paintEvent(QPaintEvent*event)

{

    //下面三个数组用来定义表针的三个顶点，以便后面的填充

        static const QPoint hourHand[3] = {

            QPoint(3, 8),

            QPoint(-3, 8),

            QPoint(0, -40)

        };

        static const QPoint minuteHand[3] = {

            QPoint(3, 8),

            QPoint(-3, 8),

            QPoint(0, -70)

        };

        static const QPoint secondHand[3] = {

            QPoint(3, 8),

            QPoint(-3, 8),

            QPoint(0, -90)

        };//秒针

        QTime time = QTime::currentTime();   //获取当前的时间

        //填充表针的颜色

        QColor hourColor(127, 0, 127);  //分针颜色(第四个表示不透明度)

        QColor minuteColor(0, 127, 127, 191);

        QColor secondColor(127, 127, 0, 127);

        QPainter painter(this);              //声明用来绘图用的painter

        painter.setRenderHint(QPainter::Antialiasing);//绘制的图像反锯齿

        painter.translate(width() / 2, height() / 2);//重新定位坐标起始点，把坐标原点放到窗体的中央

        painter.setPen(Qt::NoPen);   //填充时针，不需要边线所以NoPen

        painter.setBrush(hourColor);  //画刷颜色设定

        painter.save();  //保存painter的状态，保存的是当前的坐标状态，如果不保存，画完之后坐标以改变不方便画下一个

        painter.rotate(30.0 * ((time.hour() + time.minute() / 60.0))); //将painter（的”视角“）根据时间参数转移(30° * (小时 + 分钟 / 60))

        painter.drawConvexPolygon(hourHand, 3);  //填充时针的区域

        painter.restore();

         //后面的跟前面的类似，分别绘制了分针和秒针，及相应的刻度

        painter.setPen(Qt::NoPen);

        painter.setBrush(minuteColor);

        painter.save();

        painter.rotate(6.0 * (time.minute() + time.second() / 60.0));  //设旋转(角度 = 6° * (分钟 + 秒 / 60))

        painter.drawConvexPolygon(minuteHand, 3);  //填充分针部分

        painter.restore();

        painter.setPen(Qt::NoPen);

        painter.setBrush(secondColor);

        painter.save();

        painter.rotate(6.0 * time.second());  //设置旋转(6° * 秒)

        painter.drawConvexPolygon(secondHand, 3);  //设置填充

        painter.restore();

        painter.setPen(minuteColor);

           for (int j = 0; j < 60; ++j) {  //循环60次，绘制表盘（其实可以从1开始，到59，提高一点效率）

               if ((j % 5) != 0)           //判断是否能被5整除(能被5整除表示是正点刻度，暂不绘制)

                   painter.drawLine(0, -92, 0, -96);  //不是正点刻度，绘制长4个像素的直线

               painter.rotate(6.0);   //循环60次，每次旋转6度，所以不用save和restore

           }

           painter.setPen(hourColor);    //下面画表示小时的刻度，此时要用到画笔（因为要划线）

           for (int i = 0; i < 12; ++i) {

               painter.drawLine(0, -88, 0, -96);     //写上刻度数字

               if (i == 0)  painter.drawText(-10,-88,20,20,Qt::AlignHCenter | Qt::AlignTop,QString::number(12));

               else  painter.drawText(-10,-88,20,20,Qt::AlignHCenter | Qt::AlignTop,QString::number(i));

               painter.rotate(30.0);

           }

          painter.setBrush(Qt::black);

          painter.drawEllipse(QPoint(0,0),2,2);

          painter.setBrush(Qt::NoBrush);

          painter.setPen(Qt::black);

          painter.drawEllipse(QPoint(0,0),97,97);

}

效果图：