Qt 通过重写QGraphicItem实现绘制、拖动、旋转、缩放椭圆

本例程通过重写了一个类，继承自QGraphicItem，来实现了在qgraphicsScene上绘制、拖动、旋转、缩放椭圆
效果如下：

核心代码如下：
mygraphicrectitem.h

#ifndef MYGRAPHICRECTITEM_H
#define MYGRAPHICRECTITEM_H
#include <QObject>
#include <QWidget>
#include <QMouseEvent>
#include <QGraphicsScene>
#include <QGraphicsRectItem>
#include <QGraphicsSceneMouseEvent>
#include <QRect>
#include <QPainter>
#include <QPolygon>
#include <QList>
#include <QTransform>
enum STATE_FLAG{
    DEFAULT_FLAG=0,
    MOV_LEFT_LINE,//标记当前为用户按下矩形的左边界区域
    MOV_TOP_LINE,//标记当前为用户按下矩形的上边界区域
    MOV_RIGHT_LINE,//标记当前为用户按下矩形的右边界区域
    MOV_BOTTOM_LINE,//标记当前为用户按下矩形的下边界区域
    MOV_RIGHTBOTTOM_RECT,//标记当前为用户按下矩形的右下角
    MOV_RECT,//标记当前为鼠标拖动图片移动状态
    ROTATE//标记当前为旋转状态
};
enum SHAPE_TYPE{
    RECTANGLE=0,
    CIRCLE
};

class myGraphicRectItem:public QObject,public QGraphicsItem
{
    Q_OBJECT
public:
    SHAPE_TYPE m_ShapeType;
    myGraphicRectItem(QGraphicsItem *parent = nullptr);
    //myGraphicRectItem(QRectF m_OriginRect = QRectF(0,0,100,100));
    QRectF  boundingRect() const;
    QPainterPath shape() const;
    QPainterPath getCollideShape();
    ~myGraphicRectItem();
    void setRectSize(QRectF mrect,bool bResetRotateCenter = true);
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
    void mousePressEvent(QGraphicsSceneMouseEvent *event);
    void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
    void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);
    void SetRotate(qreal RotateAngle);
    QPointF getRotatePoint(QPointF ptCenter, QPointF ptIn, qreal angle);//获取旋转后的点
    QList<QPointF> getRotatePoints(QPointF ptCenter,QList<QPointF> ptIns,qreal angle);//获取多个旋转后的点
    QPolygonF getRotatePolygonFromRect(QPointF ptCenter,QRectF rectIn,qreal angle);//将矩形旋转之后返回多边形
    QRectF getCrtPosRectToSceen();
    QPolygonF getCrtPolygonToScreen();

    QPointF getSmallRotateRectCenter(QPointF ptA,QPointF ptB);//获取旋转时候矩形正上方的旋转标记矩形
    QRectF  getSmallRotateRect(QPointF ptA,QPointF ptB);
    bool    m_bRotate;
    qreal   m_RotateAngle;
    QPointF m_RotateCenter;

private:
    QRectF  m_oldRect;
    QPolygonF m_oldRectPolygon;
    QRectF  m_RotateAreaRect;
    bool    m_bResize;
    QPolygonF m_insicedPolygon;
    QRectF  m_insicedRectf;
    QPolygonF m_leftPolygon;
    QRectF  m_leftRectf;
    QPolygonF m_topPolygon;
    QRectF  m_topRectf;
    QPolygonF m_rightPolygon;
    QRectF  m_rightRectf;
    QPolygonF m_bottomPolygon;
    QRectF  m_bottomRectf;
    QRectF m_SmallRotateRect;//矩形顶部用来表示旋转的标记的矩形
    QPolygonF m_SmallRotatePolygon;//矩形顶部用来表示旋转的标记的矩形旋转后形成的多边形
//    QPolygonF m_rbPolygon;
//    QRectF  m_rbRectf;
    QPointF m_startPos;
    STATE_FLAG m_StateFlag;
    QPointF *pPointFofSmallRotateRect;
protected:

};

#endif // MYGRAPHICRECTITEM_H

mygraphicrectitem.cpp

#include "mygraphicrectitem.h"
#include <QtMath>
#include <QDebug>

myGraphicRectItem::myGraphicRectItem(QGraphicsItem *parent):
    m_ShapeType(RECTANGLE),
    m_bResize(false),
    m_oldRect(0,0,100,100),
    m_bRotate(false),
    m_RotateAngle(0),
    m_StateFlag(DEFAULT_FLAG)
{
    //setParent(parent);
    setRectSize(m_oldRect);
    setToolTip("Click and drag me!");  //提示
    setCursor(Qt::ArrowCursor);   //改变光标形状,手的形状
    setFlag(QGraphicsItem::ItemIsMovable);
    pPointFofSmallRotateRect = new QPointF[4];
    SetRotate(0);
    //setFlag(QGraphicsItem::ItemIsSelectable);//
    setFlags(QGraphicsItem::ItemIsSelectable|QGraphicsItem::ItemIsMovable);
}

QRectF myGraphicRectItem::boundingRect() const//用来控制本item绘制区域
{
    QPainterPath path;
    path.addPolygon(m_oldRectPolygon);
    path.addPolygon(m_SmallRotatePolygon);
    return path.boundingRect();
}

QPainterPath myGraphicRectItem::shape() const//用来控制检测碰撞collide和鼠标点击hit响应区域
{
    QPainterPath path;
    path.addPolygon(m_oldRectPolygon);
    path.addPolygon(m_SmallRotatePolygon);
    return path;
}

QPainterPath myGraphicRectItem::getCollideShape()
{
    QPainterPath path;
    if(m_ShapeType==RECTANGLE)
    {
        path.addPolygon(m_oldRectPolygon);
    }
    else if(m_ShapeType == CIRCLE)
    {
        QPainterPath pathTemp;
        pathTemp.addEllipse(m_oldRect);
        QTransform trans;
        trans.translate(m_RotateCenter.x(),m_RotateCenter.y());
        trans.rotate(m_RotateAngle);//QTransform是绕（0,0）点旋转的，所以转之前要先平移到圆心，然后旋转，然后再平移回来
        trans.translate(-m_RotateCenter.x(),-m_RotateCenter.y());
        path = trans.map(pathTemp);
    }
    return path;
}

myGraphicRectItem::~myGraphicRectItem()
{
    delete []pPointFofSmallRotateRect;
    pPointFofSmallRotateRect = nullptr;
}

void myGraphicRectItem::setRectSize(QRectF mrect, bool bResetRotateCenter)
{
    m_oldRect = mrect;
    if(bResetRotateCenter)
    {
        m_RotateCenter.setX(m_oldRect.x()+m_oldRect.width()/2);
        m_RotateCenter.setY(m_oldRect.y()+m_oldRect.height()/2);
    }
    m_oldRectPolygon = getRotatePolygonFromRect(m_RotateCenter,m_oldRect,m_RotateAngle);

    m_insicedRectf = QRectF(m_oldRect.x()+8,m_oldRect.y()+8,m_oldRect.width()-16,m_oldRect.height()-16);
    m_insicedPolygon =getRotatePolygonFromRect(m_RotateCenter,m_insicedRectf,m_RotateAngle);

    m_leftRectf = QRectF(m_oldRect.x(),m_oldRect.y(),8,m_oldRect.height()-8);
    m_leftPolygon = getRotatePolygonFromRect(m_RotateCenter,m_leftRectf,m_RotateAngle);

    m_topRectf = QRectF(m_oldRect.x()+8,m_oldRect.y(),m_oldRect.width()-8,8);
    m_topPolygon = getRotatePolygonFromRect(m_RotateCenter,m_topRectf,m_RotateAngle);

    m_rightRectf = QRectF(m_oldRect.right()-8,m_oldRect.y()+8,8,m_oldRect.height()-16);
    m_rightPolygon = getRotatePolygonFromRect(m_RotateCenter,m_rightRectf,m_RotateAngle);

    m_bottomRectf = QRectF(m_oldRect.x(),m_oldRect.bottom()-8,m_oldRect.width()-8,8);
    m_bottomPolygon = getRotatePolygonFromRect(m_RotateCenter,m_bottomRectf,m_RotateAngle);

    m_SmallRotateRect = getSmallRotateRect(mrect.topLeft(),mrect.topRight());//矩形正上方的旋转标记矩形
    m_SmallRotatePolygon = getRotatePolygonFromRect(m_RotateCenter,m_SmallRotateRect,m_RotateAngle);

}

void myGraphicRectItem::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    QPen mPen;
//    if(this->isSelected())
//    {
//        mPen= QPen(Qt::lightGray);
//    }
//    else
//    {
        mPen= QPen(Qt::yellow);
//    }
    painter->setPen(mPen);
    if(m_ShapeType == RECTANGLE)
    {
        //绘制旋转后的矩形
        painter->drawPolygon(m_oldRectPolygon);
        //绘制旋转圆形
        mPen.setWidth(2);
        mPen.setColor(Qt::green);
        painter->setPen(mPen);
        QPointF pf = getSmallRotateRectCenter(m_oldRectPolygon[0],m_oldRectPolygon[1]);
        QRectF rect = QRectF(pf.x()-10,pf.y()-10,20,20);
        painter->drawEllipse(rect);//绘制圆形
        painter->drawPoint(pf);//绘制点
        //有重叠的情况
        if(!this->scene()->collidingItems(this).isEmpty())
        {
           QPainterPath path,pathOthers;
           QList<QGraphicsItem *> lstcolliItems = this->scene()->collidingItems(this);
           int nColliNum = lstcolliItems.count();
           for(int i = 0;i<nColliNum;i++)
           {
               myGraphicRectItem* pTempItem = (myGraphicRectItem*)this->scene()->collidingItems(this)[i];
               if(pTempItem->zValue()==0)
               {
                   QPainterPath tempPath = pTempItem->getCollideShape();
                   tempPath.translate(pTempItem->pos());//转换到view中的坐标
                   pathOthers += tempPath;//记录与本item重叠的item的路径
               }
           }
           path.addPolygon(m_oldRectPolygon);
           path.translate(this->pos());//转换到view中的坐标
           path &= pathOthers;//计算重叠部分的路径path
           path.translate(-this->pos().x(),-this->pos().y());//转换回本Item中的坐标
           QBrush brush(Qt::cyan);
           mPen.setColor(Qt::blue);
           painter->setPen(mPen);
           painter->setBrush(brush);
           painter->drawPath(path);//绘制重叠区域
        }
    }
    else if(m_ShapeType == CIRCLE)
    {
//        //绘制旋转后的矩形
//        painter->drawRect(m_oldRect);
//        painter->drawPolygon(m_oldRectPolygon);
        //绘制旋转后的圆形
        QTransform trans0;
        QPainterPath path0;
        trans0.translate(m_RotateCenter.x(),m_RotateCenter.y());
        trans0.rotate(m_RotateAngle,Qt::ZAxis);
        trans0.translate(-m_RotateCenter.x(),-m_RotateCenter.y());
        path0.addEllipse(m_oldRect);
        path0 = trans0.map(path0);//将pathTemp旋转m_RotateAngle角度
        painter->drawPath(path0);//drawPolygon(m_oldRectPolygon);
        //绘制旋转圆形标记
        mPen.setWidth(2);
        mPen.setColor(Qt::green);
        painter->setPen(mPen);
        QPointF pf = getSmallRotateRectCenter(m_oldRectPolygon[0],m_oldRectPolygon[1]);
        QRectF rect = QRectF(pf.x()-10,pf.y()-10,20,20);
        painter->drawEllipse(rect);//绘制圆形
        painter->drawPoint(pf);//绘制点
        //有重叠的情况
        if(!this->scene()->collidingItems(this).isEmpty())
        {
           QPainterPath path,pathOthers;
           QList<QGraphicsItem *> lstcolliItems = this->scene()->collidingItems(this);
           int nColliNum = lstcolliItems.count();
           for(int i = 0;i<nColliNum;i++)
           {
               myGraphicRectItem* pTempItem = (myGraphicRectItem*)this->scene()->collidingItems(this)[i];
               if(pTempItem->zValue()==0)
               {
                   QPainterPath tempPath = pTempItem->getCollideShape();
                   tempPath.translate(pTempItem->pos());//转换到view中的坐标
                   pathOthers += tempPath;//记录与本item重叠的item的路径
               }
           }
           QTransform trans;
           //旋转的时候，QTransform是绕坐标轴的（0,0）点旋转的，所以先要平移到坐标轴0，0点，然后的旋转，然后移回到原来的位置
           trans.translate(m_RotateCenter.x(),m_RotateCenter.y());
           trans.rotate(m_RotateAngle);
           trans.translate(-m_RotateCenter.x(),-m_RotateCenter.y());
           path.addEllipse(m_oldRect);
           path = trans.map(path);//将pathTemp旋转m_RotateAngle角度
           path.translate(this->pos());//转换到view中的坐标
           path &= pathOthers;//计算重叠部分的路径path
           path.translate(-this->pos().x(),-this->pos().y());//转换回本Item中的坐标
           QBrush brush(Qt::cyan);
           mPen.setColor(Qt::blue);
           painter->setPen(mPen);
           painter->setBrush(brush);
           painter->drawPath(path);//绘制重叠区域
        }
    }
//scene()->update();
}

void myGraphicRectItem::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    if(event->button()== Qt::LeftButton)
    {
        //setSelected(true);
        m_startPos = event->pos();//鼠标左击时，获取当前鼠标在图片中的坐标，
        if(m_SmallRotatePolygon.containsPoint(m_startPos,Qt::WindingFill))//旋转矩形
        {
            setCursor(Qt::PointingHandCursor);
            m_StateFlag = ROTATE;
        }
        else if(m_insicedPolygon.containsPoint(m_startPos,Qt::WindingFill))//在矩形内框区域时按下鼠标，则可拖动图片
        {
            setCursor(Qt::ClosedHandCursor);   //改变光标形状,手的形状
            m_StateFlag = MOV_RECT;//标记当前为鼠标拖动图片移动状态
        }
        else if(m_leftPolygon.containsPoint(m_startPos,Qt::WindingFill))
        {
            setCursor(Qt::SizeHorCursor);
            m_StateFlag = MOV_LEFT_LINE;//标记当前为用户按下矩形的左边界区域
        }
        else if(m_rightPolygon.containsPoint(m_startPos,Qt::WindingFill))
        {
            setCursor(Qt::SizeHorCursor);
            m_StateFlag = MOV_RIGHT_LINE;//标记当前为用户按下矩形的右边界区域
        }
        else if(m_topPolygon.containsPoint(m_startPos,Qt::WindingFill))
        {
            setCursor(Qt::SizeVerCursor);
            m_StateFlag = MOV_TOP_LINE;//标记当前为用户按下矩形的上边界区域
        }
        else if(m_bottomPolygon.containsPoint(m_startPos,Qt::WindingFill))
        {
            setCursor(Qt::SizeVerCursor);
            m_StateFlag = MOV_BOTTOM_LINE;//标记当前为用户按下矩形的下边界区域
        }
//        else if(m_rbPolygon.containsPoint(m_startPos,Qt::WindingFill))
//        {
//            setCursor(Qt::SizeFDiagCursor);
//            m_StateFlag = MOV_RIGHTBOTTOM_RECT;//标记当前为用户按下矩形的右下角
//        }
        else
        {
            m_StateFlag = DEFAULT_FLAG;
        }
    }
    else
    {
        QGraphicsItem::mousePressEvent(event);
    }
}

void myGraphicRectItem::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
    if(m_StateFlag == ROTATE)
    {
       int nRotateAngle = atan2((event->pos().x()-m_RotateCenter.x()),(event->pos().y()-m_RotateCenter.y()))*180/M_PI;
       SetRotate(180-nRotateAngle);       
       //qDebug()<<nRotateAngle;
    }
    else if(m_StateFlag == MOV_RECT)
    {
        QPointF point = (event->pos() - m_startPos);
        moveBy(point.x(), point.y());
        setRectSize(m_oldRect);
        scene()->update();
    }
    else if(m_StateFlag == MOV_LEFT_LINE)
    {
        QPointF pf = QPointF((m_oldRectPolygon.at(1).x()+m_oldRectPolygon.at(2).x())/2,((m_oldRectPolygon.at(1).y()+m_oldRectPolygon.at(2).y())/2));
        //计算到右侧边中点的距离
        qreal dis = sqrt((event->pos().x()-pf.x())*(event->pos().x()-pf.x()) +(event->pos().y()-pf.y())*(event->pos().y()-pf.y()));
        qreal dis2LT = sqrt((event->pos().x()-m_oldRectPolygon.at(0).x())*(event->pos().x()-m_oldRectPolygon.at(0).x()) +(event->pos().y()-m_oldRectPolygon.at(0).y())*(event->pos().y()-m_oldRectPolygon.at(0).y()));
        qreal dis2RT = sqrt((event->pos().x()-m_oldRectPolygon.at(1).x())*(event->pos().x()-m_oldRectPolygon.at(1).x()) +(event->pos().y()-m_oldRectPolygon.at(1).y())*(event->pos().y()-m_oldRectPolygon.at(1).y()));
        if(dis<16||dis2LT>dis2RT)
        {
            return;
        }
        else
        {
            QRectF newRect(m_oldRect);
            newRect.setLeft(m_oldRect.right()-dis);
            newRect.setRight(m_oldRect.right());
            setRectSize(newRect,false);
            m_RotateCenter=QPointF((m_oldRectPolygon.at(0).x()+m_oldRectPolygon.at(2).x())/2,(m_oldRectPolygon.at(0).y()+m_oldRectPolygon.at(2).y())/2);
            m_oldRect.moveCenter(m_RotateCenter);
            setRectSize(m_oldRect);
            scene()->update();//必须要用scene()->update()，不能用update();否则会出现重影
        }
    }
    else if(m_StateFlag == MOV_TOP_LINE)
    {
        //底边中点
        QPointF pf = QPointF((m_oldRectPolygon.at(2).x()+m_oldRectPolygon.at(3).x())/2,((m_oldRectPolygon.at(2).y()+m_oldRectPolygon.at(3).y())/2));
        //计算到底边中点的距离
        qreal dis = sqrt((event->pos().x()-pf.x())*(event->pos().x()-pf.x()) +(event->pos().y()-pf.y())*(event->pos().y()-pf.y()));
        qreal dis2LT = sqrt((event->pos().x()-m_oldRectPolygon.at(0).x())*(event->pos().x()-m_oldRectPolygon.at(0).x()) +(event->pos().y()-m_oldRectPolygon.at(0).y())*(event->pos().y()-m_oldRectPolygon.at(0).y()));
        qreal dis2LB = sqrt((event->pos().x()-m_oldRectPolygon.at(3).x())*(event->pos().x()-m_oldRectPolygon.at(3).x()) +(event->pos().y()-m_oldRectPolygon.at(3).y())*(event->pos().y()-m_oldRectPolygon.at(3).y()));
        if(dis<16||dis2LT>dis2LB)
        {
            return;
        }
        else
        {
            QRectF newRect(m_oldRect);
            newRect.setTop(m_oldRect.bottom()-dis);
            newRect.setBottom(m_oldRect.bottom());
            setRectSize(newRect,false);
            m_RotateCenter=QPointF((m_oldRectPolygon.at(0).x()+m_oldRectPolygon.at(2).x())/2,(m_oldRectPolygon.at(0).y()+m_oldRectPolygon.at(2).y())/2);
            m_oldRect.moveCenter(m_RotateCenter);
            setRectSize(m_oldRect);
            scene()->update();//必须要用scene()->update()，不能用update();否则会出现重影
        }
    }
    else if(m_StateFlag == MOV_RIGHT_LINE)
    {
        QPointF pf = QPointF((m_oldRectPolygon.at(0).x()+m_oldRectPolygon.at(3).x())/2,((m_oldRectPolygon.at(0).y()+m_oldRectPolygon.at(3).y())/2));
        //计算到左侧边中点的距离
        qreal dis = sqrt((event->pos().x()-pf.x())*(event->pos().x()-pf.x()) +(event->pos().y()-pf.y())*(event->pos().y()-pf.y()));
        qreal dis2LT = sqrt((event->pos().x()-m_oldRectPolygon.at(0).x())*(event->pos().x()-m_oldRectPolygon.at(0).x()) +(event->pos().y()-m_oldRectPolygon.at(0).y())*(event->pos().y()-m_oldRectPolygon.at(0).y()));
        qreal dis2RT = sqrt((event->pos().x()-m_oldRectPolygon.at(1).x())*(event->pos().x()-m_oldRectPolygon.at(1).x()) +(event->pos().y()-m_oldRectPolygon.at(1).y())*(event->pos().y()-m_oldRectPolygon.at(1).y()));
        if(dis<16||dis2LT<dis2RT)
        {
            return;
        }
        else
        {
            QRectF newRect(m_oldRect);
            newRect.setLeft(m_oldRect.left());
            newRect.setRight(m_oldRect.left()+dis);
            setRectSize(newRect,false);
            m_RotateCenter=QPointF((m_oldRectPolygon.at(0).x()+m_oldRectPolygon.at(2).x())/2,(m_oldRectPolygon.at(0).y()+m_oldRectPolygon.at(2).y())/2);
            m_oldRect.moveCenter(m_RotateCenter);
            setRectSize(m_oldRect);
            scene()->update();//必须要用scene()->update()，不能用update();否则会出现重影
        }
    }
    else if(m_StateFlag == MOV_BOTTOM_LINE)
    {
        //顶边中点
        QPointF pf = QPointF((m_oldRectPolygon.at(0).x()+m_oldRectPolygon.at(1).x())/2,((m_oldRectPolygon.at(0).y()+m_oldRectPolygon.at(1).y())/2));
        //计算到底边中点的距离
        qreal dis = sqrt((event->pos().x()-pf.x())*(event->pos().x()-pf.x()) +(event->pos().y()-pf.y())*(event->pos().y()-pf.y()));
        qreal dis2LT = sqrt((event->pos().x()-m_oldRectPolygon.at(0).x())*(event->pos().x()-m_oldRectPolygon.at(0).x()) +(event->pos().y()-m_oldRectPolygon.at(0).y())*(event->pos().y()-m_oldRectPolygon.at(0).y()));
        qreal dis2LB = sqrt((event->pos().x()-m_oldRectPolygon.at(3).x())*(event->pos().x()-m_oldRectPolygon.at(3).x()) +(event->pos().y()-m_oldRectPolygon.at(3).y())*(event->pos().y()-m_oldRectPolygon.at(3).y()));
        if(dis<16||dis2LT<dis2LB)
        {
            return;
        }
        else
        {
            QRectF newRect(m_oldRect);
            newRect.setTop(m_oldRect.top());
            newRect.setBottom(m_oldRect.top()+dis);
            setRectSize(newRect,false);
            m_RotateCenter=QPointF((m_oldRectPolygon.at(0).x()+m_oldRectPolygon.at(2).x())/2,(m_oldRectPolygon.at(0).y()+m_oldRectPolygon.at(2).y())/2);
            m_oldRect.moveCenter(m_RotateCenter);
            setRectSize(m_oldRect);
            scene()->update();//必须要用scene()->update()，不能用update();否则会出现重影
        }
    }
}

void myGraphicRectItem::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
    setCursor(Qt::ArrowCursor);
    if(m_StateFlag == MOV_RECT)
    {
        m_StateFlag = DEFAULT_FLAG;
    }
    else {
        QGraphicsItem::mouseReleaseEvent(event);
    }
}

void myGraphicRectItem::SetRotate(qreal RotateAngle)
{
    m_bRotate = true;
    m_RotateAngle = RotateAngle;
    setRectSize(m_oldRect);
    if(this->scene()!=nullptr)
        this->scene()->update();
}

QPointF myGraphicRectItem::getRotatePoint(QPointF ptCenter, QPointF ptIn, qreal angle)
{
    double dx = ptCenter.x();
    double dy = ptCenter.y();
    double x = ptIn.x();
    double y = ptIn.y();
    double xx,yy;
    xx = (x-dx)*cos(angle*M_PI/180)-(y-dy)*sin(angle*M_PI/180)+dx;
    yy = (x-dx)*sin(angle*M_PI/180)+(y-dy)*cos(angle*M_PI/180)+dy;

    return QPointF(xx,yy);
}

QList<QPointF> myGraphicRectItem::getRotatePoints(QPointF ptCenter, QList<QPointF> ptIns, qreal angle)
{
    QList<QPointF> lstPt;
    for(int i = 0;i<ptIns.count();i++)
    {
        lstPt.append(getRotatePoint(ptCenter,ptIns.at(i),angle));
    }
    return lstPt;
}

QPolygonF myGraphicRectItem::getRotatePolygonFromRect(QPointF ptCenter, QRectF rectIn, qreal angle)
{
    QVector<QPointF> vpt;
    QPointF pf = getRotatePoint(ptCenter,rectIn.topLeft(),angle);
    vpt.append(pf);
    pf = getRotatePoint(ptCenter,rectIn.topRight(),angle);
    vpt.append(pf);
    pf = getRotatePoint(ptCenter,rectIn.bottomRight(),angle);
    vpt.append(pf);
    pf = getRotatePoint(ptCenter,rectIn.bottomLeft(),angle);
    vpt.append(pf);
    pf = getRotatePoint(ptCenter,rectIn.topLeft(),angle);
    vpt.append(pf);
    return QPolygonF(vpt);
}

QRectF myGraphicRectItem::getCrtPosRectToSceen()
{
    QRectF retRect = QRectF(m_oldRect.x()+pos().x(),m_oldRect.y()+pos().y(),m_oldRect.width(),m_oldRect.height());
    return retRect;
}

QPolygonF myGraphicRectItem::getCrtPolygonToScreen()
{
    QVector<QPointF> vpt;
    for(int i = 0;i<m_oldRectPolygon.length();i++)
    {
        vpt.append(QPointF(m_oldRectPolygon[i].x()+pos().x(),m_oldRectPolygon[i].y()+pos().y()));
    }
    return QPolygonF(vpt);
}
QRectF myGraphicRectItem::getSmallRotateRect(QPointF ptA,QPointF ptB)
{
    QPointF pt = getSmallRotateRectCenter(ptA,ptB);
    return QRectF(pt.x()-10,pt.y()-10,20,20);
}
QPointF myGraphicRectItem::getSmallRotateRectCenter(QPointF ptA,QPointF ptB)
{
    QPointF ptCenter = QPointF((ptA.x()+ptB.x())/2,(ptA.y()+ptB.y())/2);//A,B点的中点C
    //中垂线方程式为 y=x*k + b;
    qreal x,y;//旋转图标矩形的中心
    if(abs(ptB.y()-ptA.y())<0.1)
    {
        if(ptA.x()<ptB.x())//矩形左上角在上方
        {
            x = ptCenter.x();
            y = ptCenter.y()-20;
        }
        else//矩形左上角在下方
        {
            x = ptCenter.x();
            y = ptCenter.y()+20;
        }
    }
    else if(ptB.y()>ptA.y())//顺时针旋转0-180
    {
        qreal k = (ptA.x()-ptB.x())/(ptB.y()-ptA.y());//中垂线斜率
        qreal b = (ptA.y()+ptB.y())/2-k*(ptA.x()+ptB.x())/2;
        //求AB线中垂线上离AB中点20个像素的点C的坐标
        x = 20*cos(atan(k))+ptCenter.x();
        y = k*x+b;
    }
    else if(ptB.y()<ptA.y())//顺时针旋转180-360
    {
        qreal k = (ptA.x()-ptB.x())/(ptB.y()-ptA.y());//中垂线斜率
        qreal b = (ptA.y()+ptB.y())/2-k*(ptA.x()+ptB.x())/2;
        //求AB线中垂线上离AB中点20个像素的点C的坐标
        x = -20*cos(atan(k))+ptCenter.x();
        y = k*x+b;
    }
    return QPointF(x,y);
}