Перерисовка графика при изменении размера виджета

QWidget::paintEngine: Should no longer be called
QPainter::begin: Paint device returned engine == 0, type: 1
QPainter::setBrush: Painter not active
QPainter::setPen: Painter not active
QWidget::repaint: Recursive repaint detected

#include "sortgraphic.h"
#include <QGraphicsScene>
 
SortGraphic::SortGraphic(QWidget *parent) : QGraphicsView(parent)
{
    this->scene = new QGraphicsScene();
    this->setScene(scene);
    defaultPen = new QPen(Qt::red);
    comparePen = new QPen(Qt::blue);
    movePen = new QPen(Qt::green);
}
 
void SortGraphic::setArray(QVector<int> *arr)
{
    this->arr = arr;
    this->update();
}
 
void QSortGraphic::drawArray()
{
    scene->clear();
    if(arr->size())
    {
        int max=arr->first();
        foreach (int x, *arr) {
            if(x>max) max=x;
        }
        for(int i=0;i<arr->size();i++ )
        {
            scene->addLine(0,(this->height()/arr->size())*i,(this->width()/max)*arr->at(i),(this->height()/arr->size())*i,*defaultPen);
        }
    }
}
 
void SortGraphic::paintEvent(QPaintEvent *event)
{
    QPainter *painter = new QPainter(this);
    painter->setBrush(Qt::SolidPattern);
    painter->setPen(*defaultPen);
    if(arr->size())
    {
        int max=arr->first();
        foreach (int x, *arr) {
            if(x>max) max=x;
        }
        for(int i=0;i<arr->size();i++ )
        {
            painter->drawLine(0,(this->height()/arr->size())*i,(this->width()/max)*arr->at(i),(this->height()/arr->size())*i);
        }
    }
}

#ifndef SORTGRAPHIC_H
#define SORTGRAPHIC_H
 
#include <QWidget>
#include <QGraphicsView>
#include <QVector>
#include <QPen>
#include <QGraphicsScene>
 
class SortGraphic : public QGraphicsView
{
    Q_OBJECT
public:
    explicit SortGraphic(QWidget *parent);
    void setArray(QVector<int> *arr);
 
private:
    QVector<int> *arr;
    QGraphicsScene *scene;
    int linewidth;
    QPen *defaultPen;
    QPen *comparePen;
    QPen *movePen;
protected:
    virtual void paintEvent(QPaintEvent *event);
signals:
 
public slots:
    void drawArray();
//    void swap(int a, int b);
//    void move(int from, int to);
//    void copy(int from, int to);
//    void compare(int min, int max);
//    void set(int pos, int value);
 
 
};
 
#endif // SORTGRAPHIC_H

#include "mainwindow.h"
#include "ui_mainwindow.h"
#include "sortgraphic.h"
#include <QVector>
#include <random>
 
MainWindow::MainWindow(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::MainWindow)
{
    ui->setupUi(this);
}
 
MainWindow::~MainWindow()
{
    delete ui;
}
 
void MainWindow::on_StartStop1_clicked()
{
    QVector<int> *arr = new QVector<int>();
    for(int i=1;i<50;i++) arr->append(i);
    ui->Gr1->setArray(arr);
}