用Qt画一个全方位雷达扫描

#include <QPainter> #include <QWidget> #include <QTimer> #include <qmath.h> #include <QApplication> class Radar : public QWidget { public: Radar(QWidget *parent = 0); protected: void paintEvent(QPaintEvent *event); private: QTimer *timer; float angle; }; Radar::Radar(QWidget *parent) : QWidget(parent), angle(0) { timer = new QTimer(this); connect(timer, SIGNAL(timeout()), this, SLOT(update())); timer->start(10); // 每10毫秒进行一次更新 } void Radar::paintEvent(QPaintEvent * /* event */) { QPainter painter(this); painter.setRenderHint(QPainter::Antialiasing); // 绘制雷达扫描区域 painter.setPen(QColor("#00ff00")); painter.drawEllipse(10, 10, width() - 20, height() - 20); // 绘制雷达扫描线 painter.setPen(QColor("#ff0000")); painter.drawLine(width() / 2, height() / 2, width() / 2 + (width() - 20) / 2 * qCos(qDegreesToRadians(angle)), height() / 2 + (height() - 20) / 2 * qSin(qDegreesToRadians(angle))); // 绘制雷达扫描中心点 painter.setBrush(QColor("#ff0000")); painter.drawEllipse(width() / 2 - 5, height() / 2 - 5, 10, 10); angle = (angle + 1) ;// 更新雷达扫描角度 } int main(int argc, char *argv[]) { QApplication app(argc, argv); Radar radar; radar.setWindowTitle("radar"); radar.resize(400, 400); radar.show(); return app.exec(); }