QT实现动态时钟

#ifndef MAINWINDOW_H
#define MAINWINDOW_H

#include <QMainWindow>

QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACE

class MainWindow : public QMainWindow
{
 Q_OBJECT

public:
 MainWindow(QWidget *parent = nullptr);
 ~MainWindow();
 void paintEvent(QPaintEvent *event); //重载paintEvent函数
 void timerEvent(QTimerEvent *event); //重载timerEvent函数

private:
 Ui::MainWindow *ui;
 int second=0; //该变量用来记录秒针旋转度数
 double minute=0,hour=0;//该变量分别用来记录分针，时针旋转度数
 QPixmap pic; //用来保存导入的背景位图
};
#endif // MAINWINDOW_H

#include "mainwindow.h"

#include <QApplication>

int main(int argc, char *argv[])
{
 QApplication a(argc, argv);
 MainWindow w;
 w.show();
 return a.exec();
}

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include<QPainter>
#define PI 3.1415926
#define WIDE 1000
#define HIGHT 1000
MainWindow::MainWindow(QWidget *parent)
 : QMainWindow(parent)
 , ui(new Ui::MainWindow)
{
 ui->setupUi(this);
 resize(WIDE,HIGHT);
 startTimer(1000);

}

MainWindow::~MainWindow()
{
 delete ui;
}
void MainWindow::timerEvent(QTimerEvent *event)//该函数每秒执行一次
{
 second+=6;  //秒针刻度+6°
 minute+=0.1; //秒针刻度+0.1°(秒针速度/60)
 hour+=0.0016666667; //秒针刻度+0.0016666667°(秒针速度/3600)
 repaint();
}
void MainWindow::paintEvent(QPaintEvent *event)
{
 QPainter painter(this);
 QPixmap pix(":/new/prefix1/1.png"); //导入背景位图
 pic=pix;
 QRect p(0,0,1000,1000);
 QRect p2(0,0,1000,1000);
 painter.drawPixmap(p2,pic,p);  //以原有尺寸从界面（0，0）点绘制位图
 painter.translate(WIDE/2-10,HIGHT/2); //设置绘图原点坐标为(WIDE/2-10,HIGHT/2)(此处坐标即为表盘中心，便于接下来的指针即刻度线绘制时的旋转操作)
 painter.drawEllipse(QPoint(10,0),327,327);
 painter.setBrush(QBrush(QColor(0,0,0)));
 painter.drawEllipse(QPoint(0,0),10,10);
 for (int i=1;i<=12;i++)
 {
  QFont font;      //设置字体
  font.setPointSize(17); //设置字体大小
  font.setFamily("Microsoft YaHei"); //设置字体样式
  font.setLetterSpacing(QFont::AbsoluteSpacing,0);
  painter.setFont(font);
  QString s=QString("%1").arg(i); //将int型变量i转化为Qstring类型以便用drawText函数画在窗口
  painter.drawText(QPoint(290*cos(PI*(i-1)/6-PI/3),290*sin(PI*(i-1)/6-PI/3)+10),s);    //将数字1-12在窗口画在以原点为中心，290为半径的圆上每次绘画后角度顺时针旋转30°
 }
 for (int i=0;i<=60;i++) //表盘刻度的绘制以及颜色渐变的实现
 {
  painter.translate(WIDE/2,HIGHT/2); //设置绘图原点为(WIDE/2,HIGHT/2)
  if(i*12<255) //从六点左边一格的刻度开始绘制，且每次绘制时以i为变量改变rgb颜色实现钟表刻度填充色的渐变
  {
   painter.setBrush(QBrush(QColor(0,0,i*12)));  
  }
  else if(i*12>255&i*12<510)
  {
   painter.setBrush(QBrush(QColor(0,((42-i)*12)%255,0)));
  }
  else
  {
   painter.setBrush(QBrush(QColor(((63-i)*12)%255,0,0)));
  }
  if(i%5==0)  //当i为5的倍数时绘制较长刻度线 绘制方法为通过rotate函数以之前设置的原点为旋转轴旋转一定角度到相应刻度线位置
  {
   painter.rotate(6*i);
   painter.drawRect(0,327,4,-30);

  }
  else
  {
   painter.rotate(6*i);
   painter.drawRect(0,327,2,-20);
  }
  painter.resetTransform(); //重置绘图中心
 }
 painter.setBrush(QBrush(QColor(0,0,0))); //设置黑色填充色
  painter.translate(WIDE/2-10,HIGHT/2); //绘制秒针
 painter.rotate(second);  //以原点为轴旋转相应角度以指向相应刻度 下同
 painter.drawRect(-5,-320,10,320);
 painter.resetTransform();
 painter.translate(WIDE/2-10,HIGHT/2); //绘制分针
 painter.rotate(minute);
 painter.drawRect(-3,-300,6,300);
 painter.resetTransform();
 painter.translate(WIDE/2-10,HIGHT/2); //绘制时针
 painter.rotate(hour);
 painter.drawRect(-7,-180,14,180);
 painter.resetTransform();

}