QT小项目-雷达界面（三）绘制扫描效果

#include "widget.h" #include "ui_widget.h" #include <QPainter> #include <QtMath> #include <QTimer> #include <QDebug> int flag = 0;//角度正转反转标志位 Widget::Widget(QWidget *parent) : QWidget(parent), ui(new Ui::Widget) { ui->setupUi(this); resize(1600,900); setStyleSheet("background-color:black"); QTimer *timer = new QTimer(this); timer->start(50); connect(timer,&QTimer::timeout,this,&Widget::timerTimeout); } Widget::~Widget() { delete ui; } void Widget::paintEvent(QPaintEvent *) { QPainter painter(this); QPen pen; painter.setRenderHint(QPainter::Antialiasing); pen.setColor(Qt::green); painter.setPen(pen); painter.drawArc(100,100,1400,1400,0*16,180*16); painter.drawArc(240,240,1120,1120,0*16,180*16); painter.drawArc(380,380,840,840,0*16,180*16); painter.drawArc(520,520,560,560,0*16,180*16); painter.drawArc(660,660,280,280,0*16,180*16); painter.drawLine(0,800,1600,800); painter.save(); painter.translate(800,800); painter.rotate(-30); painter.drawLine(0,0,750,0); painter.rotate(-30); painter.drawLine(0,0,750,0); painter.rotate(-30); painter.drawLine(0,0,750,0); painter.rotate(-30); painter.drawLine(0,0,750,0); painter.rotate(-30); painter.drawLine(0,0,750,0); painter.rotate(-30); painter.drawLine(0,0,750,0); painter.restore(); QFont font("Buxton Sketch",30,QFont::Bold,true); painter.setFont(font); painter.setPen(Qt::white); painter.save(); painter.translate(800,800); painter.drawText(730,0,"0°"); painter.drawText(730 * qCos(qDegreesToRadians(30.0)),730 * qSin(qDegreesToRadians(-30.0)),"30°"); //注意这里的-30° painter.drawText(730 * qCos(qDegreesToRadians(60.0)),730 * qSin(qDegreesToRadians(-60.0)),"60°"); painter.drawText(730 * qCos(qDegreesToRadians(90.0)),730 * qSin(qDegreesToRadians(-90.0)),"90°"); painter.drawText(730 * qCos(qDegreesToRadians(90.0)),730 * qSin(qDegreesToRadians(-90.0)),"90°"); painter.drawText(730 * qCos(qDegreesToRadians(120.0)),730 * qSin(qDegreesToRadians(-120.0)),"120°"); painter.drawText(730 * qCos(qDegreesToRadians(150.0)),730 * qSin(qDegreesToRadians(-150.0)),"150°"); painter.drawText(730 * qCos(qDegreesToRadians(180.0)),730 * qSin(qDegreesToRadians(-180.0)),"180°"); painter.setFont(QFont("Buxton Sketch",10,QFont::Bold,true)); painter.drawText(140,5,"10cm"); painter.drawText(280,5,"20cm"); painter.drawText(420,5,"30cm"); painter.drawText(560,5,"40cm"); painter.drawText(700,5,"50cm"); pen.setWidth(15); painter.setPen(pen); painter.drawLine(0,0,700 * qCos(qDegreesToRadians(angle1)),-700 * qSin(qDegreesToRadians(angle1))); double angle = angle1; if(flag == 0) { for(int num = 1; num <= angle; num ++) { painter.setOpacity(1 - num * 1.0 / ((angle > 30)? 30 : angle)); painter.drawLine(0,0,700 * qCos(qDegreesToRadians(angle - num)),-700 * qSin(qDegreesToRadians(angle - num))); if(num == 30) break; } } else if(flag == 1) { for(int num = 1; num <= angle; num ++) { painter.setOpacity(1 - num * 1.0 / ((180 -angle > 30)? 30 : (180 - angle))); painter.drawLine(0,0,700 * qCos(qDegreesToRadians(angle - num)),-700 * qSin(qDegreesToRadians(angle - num))); if(num == 30) break; } } } void Widget::timerTimeout() { //更新角度 if(flag == 0) { angle1++; if(angle1 == 180) flag = 1; } else { angle1--; if(angle1 == 0) flag = 0; } update(); }