QGraphicsObject motion animations is distorting object

[mvbhavsar]

I have created a wheel shape as QGraphicsObject and wanted to move along X-Axis using QPropertyAnimation. When I move this object, it gets distorted as attached in picture. My code is as follows.

#ifndef SHAPE_H
#define SHAPE_H
 
#include <QGraphicsObject>
#include <QtGui>
 
class shape : public QGraphicsObject
{
    Q_OBJECT
public:
    explicit shape(QGraphicsItem *parent = 0);
    QRectF boundingRect() const{ return QRectF(0,0,150,150);}
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
 
signals:
 
public slots:
 
};
 
#endif // SHAPE_H

#ifndef SHAPE_H
#define SHAPE_H

#include <QGraphicsObject>
#include <QtGui>

class shape : public QGraphicsObject
{
    Q_OBJECT
public:
    explicit shape(QGraphicsItem *parent = 0);
    QRectF boundingRect() const{ return QRectF(0,0,150,150);}
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);

signals:

public slots:

};

#endif // SHAPE_H

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#include "shape.h"
 
shape::shape(QGraphicsItem *parent) :
    QGraphicsObject(parent)
{
}
 
void shape::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    painter->setRenderHint(QPainter::Antialiasing);
    painter->setPen(QPen(Qt::red,20));
    painter->setBrush(Qt::transparent);
    painter->drawEllipse(0,0,100,100);
 
    painter->drawLine(50,0,50,100);
    painter->drawLine(0,50,100,50);
 
    painter->drawEllipse(40,40,20,20);
}

#include "shape.h"

shape::shape(QGraphicsItem *parent) :
    QGraphicsObject(parent)
{
}

void shape::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    painter->setRenderHint(QPainter::Antialiasing);
    painter->setPen(QPen(Qt::red,20));
    painter->setBrush(Qt::transparent);
    painter->drawEllipse(0,0,100,100);

    painter->drawLine(50,0,50,100);
    painter->drawLine(0,50,100,50);

    painter->drawEllipse(40,40,20,20);
}

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#ifndef WHEEL_H
#define WHEEL_H
 
#include <QMainWindow>
#include <QtGui>
#include "shape.h"
 
namespace Ui {
    class wheel;
}
 
class wheel : public QMainWindow
{
    Q_OBJECT
 
public:
    explicit wheel(QWidget *parent = 0);
    ~wheel();
 
private:
    Ui::wheel *ui;
    QGraphicsScene *scene;
};
 
#endif // WHEEL_H

#ifndef WHEEL_H
#define WHEEL_H

#include <QMainWindow>
#include <QtGui>
#include "shape.h"

namespace Ui {
    class wheel;
}

class wheel : public QMainWindow
{
    Q_OBJECT

public:
    explicit wheel(QWidget *parent = 0);
    ~wheel();

private:
    Ui::wheel *ui;
    QGraphicsScene *scene;
};

#endif // WHEEL_H

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#include "wheel.h"
#include "ui_wheel.h"
 
wheel::wheel(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::wheel)
{
    ui->setupUi(this);
    scene = new QGraphicsScene;
    scene->setSceneRect(0,0,1,1);
    ui->graphicsView->setCacheMode(QGraphicsView::CacheBackground);
    ui->graphicsView->setRenderHints(QPainter::Antialiasing|QPainter::SmoothPixmapTransform);
    ui->graphicsView->setScene(scene);
    shape *s = new shape;
    s->setPos(100,100);
    scene->addItem(s);
    QPropertyAnimation *anim1 = new QPropertyAnimation(s,"pos");
    anim1->setDuration(5000);
    anim1->setEndValue(QPointF(300,100));
    anim1->start();
    ui->graphicsView->update();
}
 
wheel::~wheel()
{
    delete ui;
}

#include "wheel.h"
#include "ui_wheel.h"

wheel::wheel(QWidget *parent) :
    QMainWindow(parent),
    ui(new Ui::wheel)
{
    ui->setupUi(this);
    scene = new QGraphicsScene;
    scene->setSceneRect(0,0,1,1);
    ui->graphicsView->setCacheMode(QGraphicsView::CacheBackground);
    ui->graphicsView->setRenderHints(QPainter::Antialiasing|QPainter::SmoothPixmapTransform);
    ui->graphicsView->setScene(scene);
    shape *s = new shape;
    s->setPos(100,100);
    scene->addItem(s);
    QPropertyAnimation *anim1 = new QPropertyAnimation(s,"pos");
    anim1->setDuration(5000);
    anim1->setEndValue(QPointF(300,100));
    anim1->start();
    ui->graphicsView->update();
}

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

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#include <QtGui/QApplication>
#include "wheel.h"
 
int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    wheel w;
    w.show();
 
    return a.exec();
}

#include <QtGui/QApplication>
#include "wheel.h"

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    wheel w;
    w.show();

    return a.exec();
}

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[norobro]

Try compensating for your pen size in shape::boundingRect(). See here.