qt怎么实现点击某个地方，生成一张可拖动并且放下的图片

qt怎么实现点击某个地方（可以是某个用绘图事件画了图片的空区域，也可以是label，qpushbutton等控件，方便实现即可），生成一张可拖动并且在鼠标释放的时候，放在界面上的图片

通过mousePressEvent、mouseMoveEvent、mouseReleaseEvent组合即可实现

能搞定吗？不能的话告诉我!

#ifndef QSELECTWIDGET_H
#define QSELECTWIDGET_H
 
#include <QWidget>
#include <QHash>
 
class WidgetHandle: public QWidget
{
    Q_OBJECT
public:
    enum Type
    {
        LeftTop,
        Top,
        RightTop,
        Right,
        RightBottom,
        Bottom,
        LeftBottom,
        Left,
 
        TypeCount
    };
    WidgetHandle(QWidget* parent,Type t);
 
    void    setWidget(QWidget *w);
    void    setCurrent(bool b);
protected:
protected:
    void paintEvent(QPaintEvent *);
    void mousePressEvent(QMouseEvent *e);
    void mouseMoveEvent(QMouseEvent *e);
    void mouseReleaseEvent(QMouseEvent *e);
 
protected:
    void    updateCursor();
    void    trySetGeometry(QWidget *w, int x, int y, int width, int height);
    void    tryResize(QWidget *w, int width, int height);
signals:
    void sizeChanged(int x,int y,int width,int height);
    void    mouse_button_release(const QRect& old,const QRect & now);
protected:
    Type        m_type;
    QWidget *   m_widget;
    bool        m_current;
    QPoint      m_origPressPos;
    QRect       m_geom, m_origGeom;
};
 
class WidgetSelection: public QObject
{
    Q_OBJECT
public:
    WidgetSelection(QWidget *parent);
 
    void setWidget(QWidget *w);
    QWidget *widget();
    bool isUsed() const;
 
    void hide();
    void show();
    void update();
    void updateGeometry();
 
    void setCurrent(bool b);
protected:
    bool eventFilter(QObject *object, QEvent *event);
 
protected slots:
    void    changedsize(int x,int y,int width,int height);
    void    mouse_button_release(const QRect& old,const QRect & now);
signals:
    void sizeChanged(QWidget* wid,const QRect& old,const QRect & now);
protected:
    WidgetHandle *m_handles[WidgetHandle::TypeCount];
    QWidget     *m_widget;
    QWidget     *m_formWindow;
};
 
class Selection :   public QObject
{
    Q_OBJECT
public:
    Selection(QWidget *formwindow);
    ~Selection();
 
    void clear();
 
    void  clearSelectionPool();
 
    void repaintSelection(QWidget *w);
    void repaintSelection();
 
    bool isWidgetSelected(QWidget *w) const;
    QWidgetList selectedWidgets() const;
 
    WidgetSelection *addWidget(QWidget *w);
    QWidget* removeWidget(QWidget *w);
    QWidget* current();
 
    void raiseList(const QWidgetList& l);
    void raiseWidget(QWidget *w);
 
    void updateGeometry(QWidget *w);
 
    void hide(QWidget *w);
    void show(QWidget *w);
 
 
    void setCurrent(QWidget *w);
signals:
    void sizeChanged(QWidget* wid,const QRect& old,const QRect & now);
 
private:
 
    typedef QList<WidgetSelection *> SelectionPool;
    SelectionPool m_selectionPool;
 
    typedef QHash<QWidget *, WidgetSelection *> SelectionHash;
    SelectionHash m_usedSelections;
    WidgetSelection *       m_current;
    QWidget*                m_formwindow;
};
 
#endif // QSELECTWIDGET_H

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