#include "ResizableRectItem.h" GraphicsItems::GraphicsItems(QGraphicsItem* parent) : QGraphicsRectItem(parent) { setFlags(QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable); m_bResizing = false; } void GraphicsItems::mousePressEvent(QGraphicsSceneMouseEvent* event) { m_pressPos = event->pos(); m_originalRect = rect(); if (m_originalRect.contains(m_pressPos)) { m_bResizing = true; setCursor(Qt::SizeAllCursor); } else { m_bResizing = false; setCursor(Qt::ClosedHandCursor); } QGraphicsRectItem::mousePressEvent(event); } void GraphicsItems::mouseMoveEvent(QGraphicsSceneMouseEvent* event) { if (m_bResizing) { QPointF delta = event->pos() - m_pressPos; QRectF newRect = m_originalRect.adjusted(0, 0, delta.x(), delta.y()); setRect(newRect); } else { QGraphicsRectItem::mouseMoveEvent(event); } } void GraphicsItems::mouseReleaseEvent(QGraphicsSceneMouseEvent* event) { m_bResizing = false; setCursor(Qt::ArrowCursor); QGraphicsRectItem::mouseReleaseEvent(event); }修改这个类，改为鼠标在矩形类可拖动矩形位置，在矩形边缘可拉伸矩形大小

要修改ResizableRectItem类，使其能够在矩形边缘拉伸大小并在矩形内部拖动位置，您可以进行以下更改：

#pragma once
#include <QGraphicsItem>
#include <QGraphicsRectItem>
#include <QGraphicsSceneMouseEvent>

class ResizableRectItem : public QGraphicsRectItem
{
public:
    ResizableRectItem(QGraphicsItem* parent = nullptr);

protected:
    void mousePressEvent(QGraphicsSceneMouseEvent* event) override;
    void mouseMoveEvent(QGraphicsSceneMouseEvent* event) override;
    void mouseReleaseEvent(QGraphicsSceneMouseEvent* event) override;

private:
    QPointF m_pressPos;
    QRectF m_originalRect;
    bool m_bResizing;
};

在这个修改过的类中，我们将类名从GraphicsItems改为ResizableRectItem，并将其作为一个独立的类。

接下来，我们需要在类的构造函数中添加缩放和移动的标志：

ResizableRectItem::ResizableRectItem(QGraphicsItem* parent)
    : QGraphicsRectItem(parent)
{
    setFlags(QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable);
    m_bResizing = false;
}

然后，我们修改鼠标事件处理函数以实现拉伸和移动功能：

void ResizableRectItem::mousePressEvent(QGraphicsSceneMouseEvent* event)
{
    m_pressPos = event->pos();
    m_originalRect = rect();

    if (m_originalRect.contains(m_pressPos))
    {
        m_bResizing = true;
        setCursor(Qt::SizeAllCursor);
    }
    else
    {
        m_bResizing = false;
        setCursor(Qt::ClosedHandCursor);
    }

    QGraphicsRectItem::mousePressEvent(event);
}

void ResizableRectItem::mouseMoveEvent(QGraphicsSceneMouseEvent* event)
{
    if (m_bResizing)
    {
        QPointF delta = event->pos() - m_pressPos;
        QRectF newRect = m_originalRect.adjusted(0, 0, delta.x(), delta.y());
        setRect(newRect);
    }
    else
    {
        QGraphicsRectItem::mouseMoveEvent(event);
    }
}

void ResizableRectItem::mouseReleaseEvent(QGraphicsSceneMouseEvent* event)
{
    m_bResizing = false;
    setCursor(Qt::ArrowCursor);
    QGraphicsRectItem::mouseReleaseEvent(event);
}

这些鼠标事件处理函数与之前的示例相同，以实现在矩形边缘拉伸大小和在矩形内部拖动位置的功能。

现在，您可以使用修改后的ResizableRectItem类来创建具有可拉伸大小和可拖动位置功能的矩形对象了。