How can I re- size the QGraphicItem using mouse

问题

I this code which creates rectangle sizeof(200x100) and ellipse sizeof(100,200) but now I need to change the size of rectangle and ellipse using mouse.how can I do this.

#include "widget.h"
#include "ui_widget.h"
#include "readsvg.h"

#include <QCursor>
#include <QFileDialog>

Widget::Widget(QWidget *parent) :
    QWidget(parent),
    ui(new Ui::Widget)
{
    ui->setupUi(this);
    scene = new QGraphicsScene(this);
    ui->graphicsView->setScene(scene);

    QBrush redBrush(Qt::red);
    QBrush blueBrush(Qt::blue);
    QPen blackPen(Qt::black);
    blackPen.setWidth(6);

    elipse = scene->addEllipse(20,20,100,100,blackPen,redBrush);
    elipse->setFlag(QGraphicsItem::ItemIsMovable, true);

    rect = scene->addRect(-20,-10,200,100,blackPen,blueBrush);
    rect->setFlag(QGraphicsItem::ItemIsMovable, true);
    rect->setFlag(QGraphicsItem::ItemIsSelectable,true);

}

Widget::~Widget()
{
    delete ui;
}

This is my expected results.

or this

来源：https://stackoverflow.com/questions/46864465/how-can-i-re-size-the-qgraphicitem-using-mouse