使用C++在Qt5中显示曲线

#include <QApplication>
#include <QWidget>
#include <QPainter>
#include <QPen>

class CurveWidget : public QWidget {
protected:
    void paintEvent(QPaintEvent *event) override {
        QPainter painter(this);
        QPen pen(Qt::blue, 2, Qt::SolidLine);
        painter.setPen(pen);

        int width = this->width();
        int height = this->height();
        int centerX = width / 2;
        int centerY = height / 2;

        for (int i = 0; i < 360; ++i) {
            double angle = qDegreesToRadians(i);
            int x = static_cast<int>(centerX + 100 * qCos(angle));
            int y = static_cast<int>(centerY + 100 * qSin(angle));
            if (i == 0) {
                painter.drawPoint(x, y);
            } else {
                painter.drawLine(prevX, prevY, x, y);
            }
            prevX = x;
            prevY = y;
        }
    }

private:
    int prevX = 0;
    int prevY = 0;
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);
    CurveWidget widget;
    widget.resize(400, 400);
    widget.show();
    return app.exec();
}