利用Qt绘制雷达扫描效果

#ifndef SCAN_H
#define SCAN_H

#include <QWidget>
#include <QPainter>
#include <Qtime>
#include <QTimer>
#include <QDebug>
#include <QPoint>
#include <QtMath>

namespace Ui {
class Scan;
}
class Scan : public QWidget
{
    Q_OBJECT
public:
    explicit Scan(QWidget *parent = nullptr);
    ~Scan();
public slots:
   void timerTimeOut();
protected:
   void paintEvent(QPaintEvent *event) override;
private slots:
   void on_pushButton_clicked();
private:
    Ui::Scan *ui;
};
#endif // SCAN_H

#include "scan.h"
#include "ui_scan.h"
QTimer *timer = new QTimer();
int m_angle=0;
int alpha=0;
double cir_size=5;
Scan::Scan(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Scan)
{
    ui->setupUi(this);
    setPalette(Qt::black); setAutoFillBackground(true);//强制设置背景颜色为黑色
    connect(timer,SIGNAL(timeout()),this,SLOT(timerTimeOut()));//用槽函数控制雷达扫描效果。
    timer->start(10);


}

Scan::~Scan()
{
    delete ui;
}

void Scan::timerTimeOut()
{
    timer->start(10);
    if(m_angle<-360){
        m_angle=0;
    }//实现无缝连接，且保证m_angle的值不会溢出
    if(alpha>=255){
        alpha = 0;
    }
    if(cir_size>10){
        cir_size=5;
    }
    update();
}
void Scan::paintEvent(QPaintEvent *event)//此函数自动执行，实现扫描动画效果
{
    Q_UNUSED(event);
    QPainter painter(this);
    QPen pen;
    painter.setRenderHint(QPainter::Antialiasing);
    painter.setPen(QPen(qRgba(128, 255, 0,250)));

    //网格改成坐标系
    int x=280;//原本为240，右移40，下移60
    int y=300;
    
    QPoint center(x,y);
    painter.drawEllipse(center,240,240);
    painter.drawEllipse(center,240-48,240-48);
    painter.drawEllipse(center,240-96,240-96);
    painter.drawEllipse(center,240-144,240-144);
    painter.drawEllipse(center,240-192,240-192);
    
    painter.translate(x,y);
    painter.setPen(QPen(qRgba(255, 255, 0,250)));
    painter.setFont(QFont("Calibri",10));
    for(int i=1;i<=360;i++){
           painter.rotate(1);
           painter.drawLine(0,-240,0,-235);
    }
    for(int i=1;i<=72;i++){
        painter.rotate(5);
        painter.drawLine(0,-240,0,-232);
    }
    for(int i=1;i<=36;i++){
        painter.setRenderHint(QPainter::Antialiasing);
        painter.rotate(10);
        painter.drawLine(0,-240,0,-228);
    }
    for(int i=1;i<=4;i++){
        painter.rotate(90);
        painter.drawLine(0,-240,0,-168);
    }
    painter.translate(-x,-y);//恢复坐标系
   
    QConicalGradient gradient(x, y, m_angle + 360);
    gradient.setColorAt(0.1, QColor(128, 255, 0, 150));
    gradient.setColorAt(0.7, QColor(0, 255, 0, 0));//尾部
    painter.setBrush(gradient);
    painter.setPen(QPen(Qt::NoPen));//去掉外框线
    if (width() > height()){
        painter.drawPie(40, 60, 480, 480, m_angle * 16, 360 * 16);
    }
    else{ painter.drawPie(40, 60, 480, 480, m_angle * 16, 360 * 16);}
    
    m_angle -= 1;//每次旋转1度
    alpha +=2;
    cir_size+=0.01;

    //模拟画出可疑点
    painter.setBrush(QBrush(QColor(50, 255, 200,alpha)));
    painter.drawEllipse(0,0,15,15);
    painter.drawEllipse(60+120,60+161,cir_size,cir_size);
    painter.drawEllipse(60+240,60+161,cir_size,cir_size);
    painter.drawEllipse(60+300,60+300,cir_size,cir_size);
    painter.setBrush(QBrush(QColor(50, 255, 200,(alpha+50)%255)));
    painter.drawEllipse(60+160,60+121,cir_size,cir_size);
    painter.drawEllipse(60+60,60+191,cir_size,cir_size);
    painter.drawEllipse(60+260,60+221,cir_size,cir_size);
    painter.setBrush(QBrush(QColor(50, 255, 200,(alpha+100)%255)));
    painter.drawEllipse(60+210,60+181,cir_size,cir_size);
    painter.drawEllipse(60+10,60+281,cir_size,cir_size);
    painter.drawEllipse(60+100,60+81,cir_size,cir_size);
 

}




void Scan::on_pushButton_clicked()
{
    m_angle=0;//将扫描动画重置并刷新数据，后面要将数据刷新的函数写在下面。
}