qt 重写继承QGraphicsView类显示直方图和xy坐标以及坐标的箭头使用画笔

可以使用QPainter在QGraphicsView上绘制直方图和坐标轴，具体实现可以参考以下代码：

class HistogramView : public QGraphicsView {
public:
    HistogramView(QWidget *parent = nullptr) : QGraphicsView(parent) {
        setRenderHint(QPainter::Antialiasing);
        setScene(new QGraphicsScene(this));
    }

    void setHistogram(const QVector<int> &data) {
        histogramData = data;
        update();
    }

protected:
    void drawForeground(QPainter *painter, const QRectF &rect) override {
        Q_UNUSED(rect);

        painter->setPen(QPen(Qt::black, 2));
        painter->setFont(QFont("Arial", 10));

        // 绘制x轴
        painter->drawLine(0, height() / 2, width(), height() / 2);
        painter->drawLine(width() - 10, height() / 2 - 5, width(), height() / 2);
        painter->drawLine(width() - 10, height() / 2 + 5, width(), height() / 2);
        painter->drawText(width() - 30, height() / 2 + 20, "x");

        // 绘制y轴
        painter->drawLine(width() / 2, 0, width() / 2, height());
        painter->drawLine(width() / 2 - 5, 10, width() / 2, 0);
        painter->drawLine(width() / 2 + 5, 10, width() / 2, 0);
        painter->drawText(width() / 2 - 20, 20, "y");

        // 绘制直方图
        painter->setPen(QPen(Qt::blue, 2));
        int barWidth = width() / histogramData.size();
        for (int i = 0; i < histogramData.size(); i++) {
            int barHeight = histogramData[i] * height() / 100;
            painter->drawRect(i * barWidth, height() / 2 - barHeight, barWidth, barHeight);
        }
    }

private:
    QVector<int> histogramData;
};

使用方法：

HistogramView *view = new HistogramView(this);
QVector<int> data = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100};
view->setHistogram(data);

这样就可以在QGraphicsView上显示直方图和坐标轴了。