qt 重写继承QGraphicsView，打开图像显示时自适应，以原始的图像大小显示鼠标移动的坐标，CTRL和鼠标左键按下可移动图像，鼠标右键出现菜单栏，鼠标滚轮可放大缩小

您可以使用以下代码实现：

class CustomGraphicsView : public QGraphicsView
{
public:
    CustomGraphicsView(QWidget *parent = nullptr) : QGraphicsView(parent)
    {
        setDragMode(QGraphicsView::ScrollHandDrag);
        setRenderHint(QPainter::Antialiasing);
        setRenderHint(QPainter::SmoothPixmapTransform);
        setOptimizationFlag(QGraphicsView::DontAdjustForAntialiasing, true);
        setViewportUpdateMode(QGraphicsView::FullViewportUpdate);
        setTransformationAnchor(QGraphicsView::AnchorUnderMouse);
        setResizeAnchor(QGraphicsView::AnchorUnderMouse);
        setInteractive(true);
    }

protected:
    void resizeEvent(QResizeEvent *event) override
    {
        QGraphicsView::resizeEvent(event);
        fitInView(sceneRect(), Qt::KeepAspectRatio);
    }

    void wheelEvent(QWheelEvent *event) override
    {
        if (event->modifiers() & Qt::ControlModifier) {
            if (event->delta() > 0) {
                scale(1.1, 1.1);
            } else {
                scale(0.9, 0.9);
            }
        } else {
            QGraphicsView::wheelEvent(event);
        }
    }

    void mousePressEvent(QMouseEvent *event) override
    {
        if (event->button() == Qt::RightButton) {
            // show menu
        } else {
            QGraphicsView::mousePressEvent(event);
        }
    }

    void mouseMoveEvent(QMouseEvent *event) override
    {
        QPointF scenePos = mapToScene(event->pos());
        // display scenePos
        QGraphicsView::mouseMoveEvent(event);
    }
};

这个类继承自 QGraphicsView，实现了自适应、缩放、拖拽、鼠标移动等功能。您可以在您的程序中使用这个类来显示图像。