请给出代码-QT开发中文网

下面是一个简单的示例代码，演示了如何使用Qt来实现一个基本的白板软件：

#include <QtWidgets>

class Whiteboard : public QWidget {
public:
    Whiteboard(QWidget *parent = nullptr) : QWidget(parent) {
        setAttribute(Qt::WA_StaticContents);
        modified = false;
        scribbling = false;
    }

    void clearImage() {
        image.fill(qRgb(255, 255, 255));
        modified = true;
        update();
    }

protected:
    void mousePressEvent(QMouseEvent *event) override {
        if (event->button() == Qt::LeftButton) {
            lastPoint = event->pos();
            scribbling = true;
        }
    }

    void mouseMoveEvent(QMouseEvent *event) override {
        if ((event->buttons() & Qt::LeftButton) && scribbling)
            drawLineTo(event->pos());
    }

    void mouseReleaseEvent(QMouseEvent *event) override {
        if (event->button() == Qt::LeftButton && scribbling) {
            drawLineTo(event->pos());
            scribbling = false;
        }
    }

    void paintEvent(QPaintEvent *event) override {
        QPainter painter(this);
        QRect dirtyRect = event->rect();
        painter.drawImage(dirtyRect, image, dirtyRect);
    }

private:
    void drawLineTo(const QPoint &endPoint) {
        QPainter painter(&image);
    	painter.setPen(Qt::black);
    	painter.drawLine(lastPoint, endPoint);
    	modified = true;

    	int rad = 2; // 设置画笔大小
    	update(QRect(lastPoint, endPoint).normalized().adjusted(-rad, -rad, +rad, +rad));
    
    	lastPoint = endPoint;
	}

	QImage image;
	QPoint lastPoint;
	bool scribbling;
	bool modified;
};

int main(int argc, char *argv[]) {
    QApplication app(argc, argv);

    Whiteboard whiteboard;
    whiteboard.resize(800, 600);
    whiteboard.show();

    QPushButton clearButton("Clear");
    QObject::connect(&clearButton, &QPushButton::clicked, &whiteboard, &Whiteboard::clearImage);
    clearButton.show();

    return app.exec();
}

这个示例使用QWidget派生的自定义类Whiteboard来创建一个白板窗口。通过处理鼠标事件，在绘图区域上实现了自由绘制功能。清空按钮可以清除画布内容。

请注意，这只是一个简单的示例，可能还需要进一步优化和添加其他功能来满足实际需求。希望对你编写白板软件有所帮助！

内容由零声教学AI助手提供，问题来源于学员提问