本文小编为大家详细介绍“怎么用Qt绘制雷达扫描效果”，内容详细，步骤清晰，细节处理妥当，希望这篇“怎么用Qt绘制雷达扫描效果”文章能帮助大家解决疑惑，下面跟着小编的思路慢慢深入，一起来学习新知识吧。
scan.h的代码如下
#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_OBJECTpublic: 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_Hscan.cpp的代码如下
#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。}效果图，雷达右上角的图标对应着on_pushButton的点击事件
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