不用滚动条，只用鼠标移动画布可以吗-Go服务器开发

当然可以！如果您希望实现一个只通过鼠标移动来拖动画布，而不使用滚动条的功能，您可以修改代码如下：

修改后的代码

#include <QApplication>
#include <QFrame>
#include <QPainter>
#include <QMouseEvent>
#include <QScrollArea>
#include <QVBoxLayout>
#include <QWidget>

class CanvasFrame : public QFrame {
    Q_OBJECT

public:
    CanvasFrame(QWidget *parent = nullptr) : QFrame(parent) {
        setFixedSize(50000, 1200); // 设置画布大小
        setBackgroundRole(QPalette::Base);
        setAutoFillBackground(true);
        lastPos = QPoint(0, 0);
    }

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

    void mouseMoveEvent(QMouseEvent *event) override {
        if (dragging) {
            int dx = event->x() - lastPos.x();
            int dy = event->y() - lastPos.y();

            // 更新画布的位置
            this->move(this->x() + dx, this->y() + dy);

            lastPos = event->pos(); // 更新最后位置
        }
    }

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

    void paintEvent(QPaintEvent *) override {
        QPainter painter(this);
        
        // 绘制网格线
        const int gridSize = 50; // 网格间距
        painter.setPen(Qt::lightGray);
        
        for (int x = 0; x <= width(); x += gridSize)
            painter.drawLine(x, 0, x, height());
        
        for (int y = 0; y <= height(); y += gridSize)
            painter.drawLine(0, y, width(), y);
    }

private:
    QPoint lastPos;
    bool dragging = false;
};

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

    QWidget window;
    window.setWindowTitle("Canvas without Scrollbar");
    
    QVBoxLayout *layout = new QVBoxLayout(&window);

    CanvasFrame *canvasFrame = new CanvasFrame();
    
    layout->addWidget(canvasFrame);

    window.resize(800, 600); // 主窗口大小
    window.show();

    return a.exec();
}

#include "main.moc"