QT 绘画功能的时钟

 .h

#ifndef WIDGET_H
#define WIDGET_H
 
#include 
#include 
#include      //信息调试类
#include 
#include         //图像引擎类
#include 
#include         //定时器类
#include    //日期类
#include 
QT_BEGIN_NAMESPACE
namespace Ui { class Widget; }
QT_END_NAMESPACE
 
class Widget : public QWidget
{
    Q_OBJECT
 
public:
    Widget(QWidget *parent = nullptr);
    ~Widget();
 
    void paintEvent(QPaintEvent *event);
    void timerEvent(QTimerEvent *e);
private slots:
 
private:
    Ui::Widget *ui;
 
    int timer_id;
    //给定时器实例化一个对象
    QTimer * timer;
    int hh=0,mm=0,ss=0;
};
#endif // WIDGET_H

 .cpp

#include "widget.h"
#include "ui_widget.h"
 
Widget::Widget(QWidget *parent)
    : QWidget(parent)
    , ui(new Ui::Widget)
{
    ui->setupUi(this);
 
    timer_id=this->startTimer(1000);
    //给定时器实例化对象
    timer=new QTimer(this);
 
    // 设置窗口的大小和标题
    setFixedSize(500, 500);
    setWindowTitle("闹钟");
 
}
 
Widget::~Widget()
{
    delete ui;
}
 
//绘制事件处理函数
void Widget::paintEvent(QPaintEvent *event)
{
 
    //实例化一个画家
    QPainter painter(this);
    // 设置反锯齿渲染
    painter.setRenderHint(QPainter::Antialiasing, true);
    //实例化一个画笔
    QPen pen;
    pen.setColor(QColor("blue"));
    //设置线型
    pen.setStyle(Qt::DashDotLine);
    //将画笔给画家安排上
    painter.setPen(pen);
    //设置基准坐标系
    painter.translate(this->width()/2,this->height()/2);
    //画个钟盘
    painter.setBrush(QBrush(QColor("skyblue")));
    painter.drawEllipse(QPoint(0,0),200,200);
 
    //绘制矢量文字
    pen.setColor(QColor("black"));
    painter.setPen(pen);
 
    //给画家设置字体
    painter.setFont(QFont("隶书",15,13));
 
    //画小时格子
    for(int i=1;i<=12;i++)
    {
        //每转30度画一个时刻
        painter.rotate(30);
        pen.setWidth(4);
        painter.setPen(pen);
 
        painter.drawLine(0,-200,0,-175);
        painter.drawText(0,-170,QString("%1").arg(i));
    }
    //画分格子
    for(int i=0;i<=59;i++)
    {
        painter.rotate(6);
        pen.setWidth(2);
        painter.setPen(pen);
 
        painter.drawLine(0,-200,0,-190);
 
    }
 
    //绘制矢量文字
    painter.translate(-this->width()/2,-this->height()/2);
    painter.drawText(this->rect(),Qt::AlignCenter,"啊啊，我饿了");
 
    //绘制指针
 
    pen.setWidth(5);
 
    painter.translate(this->width()/2,this->height()/2);
    pen.setStyle(Qt::SolidLine);    //设置线型
 
    //1、绘制秒针
    painter.save();
    painter.setPen(Qt::green);
    painter.setBrush(Qt::green);
    painter.rotate(ss*6-90);
    painter.drawLine(0,0,160,0);
    painter.restore();
 
    //2、绘制分针
    painter.save();
    painter.setPen(pen);
    painter.setPen(Qt::red);
    painter.rotate(6*(mm+ss/60.0)-90);
    painter.drawLine(0,0,140,0);
    painter.restore();
 
    //3、绘制时针
    painter.save();
    //painter.translate(this->width()/2,this->height()/2);
    pen.setWidth(4);
    painter.setPen(pen);
    painter.setPen(Qt::black);
    painter.setBrush(Qt::black);
    painter.rotate(30*(hh+mm/60.0+ss/3600.0)-90);
    painter.drawLine(0,0,90,0);
    painter.restore();
}
 
//定时器事件处理函数
void Widget::timerEvent(QTimerEvent *e)
{
    if(e->timerId() == timer_id)         //说明定时器1到位
    {
        QDateTime current = QDateTime::currentDateTime();  // 获取当前系统时间
        QTime sys_t = current.time();                       // 获取系统时间的时、分、秒
        hh = sys_t.hour();
        mm = sys_t.minute();
        ss = sys_t.second();
        update();
        qDebug()<<"hh:mm:ss"<
 
    }
}
 
 

 main函数

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