一个Qt/C++ Demo,用于实现一个用于显示瀑布图的控件效果

#pragma once

#include 
#include 
#include 
#include 
#include 
#include 

class WaterfallWidget : public QWidget {
    Q_OBJECT
public:
    explicit WaterfallWidget(QWidget* parent = nullptr) :
        QWidget(parent),
        m_cols(10),
        m_rows(30),
        m_data(m_cols * m_rows, 0),
        m_pixmap(QSize(m_cols, m_rows)),
        m_timer(new QTimer(this))
    {
        // 设置定时器，控制瀑布图的刷新速度
        m_timer->setInterval(100);
        connect(m_timer, &QTimer::timeout, this, &WaterfallWidget::onTimeout);

        QVBoxLayout* layout = new QVBoxLayout();
        QLabel* label = new QLabel();
        layout->addWidget(label);
        setLayout(layout);
        m_label = label;
    }

    ~WaterfallWidget() override {
        delete m_timer;
    }

    void start() {
        m_timer->start();
    }

    void stop() {
        m_timer->stop();
    }

private:
    void paintEvent(QPaintEvent* event) override {
        QPainter painter(this);
        painter.drawPixmap(rect(), m_pixmap);
    }

    void onTimeout() {
        // 更新数据
        for (int i = 0; i < m_cols; ++i) {
            int index = i * m_rows;
            int value = m_data[index];
            for (int j = 0; j < m_rows - 1; ++j) {
                m_data[index + j] = m_data[index + j + 1];
            }
            m_data[index + m_rows - 1] = value + rand() % 10 - 5;
        }

        // 更新图像
        QPixmap oldPixmap = m_pixmap;
        QPainter painter(&m_pixmap);
        painter.fillRect(m_pixmap.rect(), Qt::black);
        QColor color(0, 255, 0);
        for (int i = 0; i < m_cols; ++i) {
            int index = i * m_rows;
            for (int j = 0; j < m_rows; ++j) {
                int value = m_data[index + j];
                color.setAlpha(qMax(0, qMin(value, 255)));
                painter.setPen(color);
                painter.drawPoint(i, m_rows - 1 - j);
            }
        }

        if (oldPixmap.size() != m_pixmap.size()) {
            m_label->setFixedSize(m_pixmap.size());
        }
        m_label->setPixmap(m_pixmap);

        update();
    }

private:
    const int m_cols;
    const int m_rows;
    QVector m_data;
    QPixmap m_pixmap;
    QTimer* m_timer;
    QLabel* m_label;
};