Graphics is jumping

[twinding]

I have a problem with graphics that jumps when I rotate it. If you look at the text when the object is rotating you will see that the number is jumping up and down. What am I doing wrong here? I hope somebody can help on this.

I have the following source
@
#ifndef CH_H
#define CH_H

#include <QGraphicsItem>

class CH : public QGraphicsItem
{
public:
CH(qreal w, qreal h);
qreal getWidth();
void advance(int phase);
protected:
void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget);
QRectF boundingRect() const;
private:
qreal width;
qreal height;
qreal objectRotation;
};

#endif // CH_H

#include "ch.h"
#include <QPainter>
#include <QFontMetrics>
#include <QDebug>

CH::CH(qreal w, qreal h)
:
width(w),
height(h),
objectRotation(0)
{
}

void CH::paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
//painter->drawRect(-width/2,-height/2,width,height/3);

painter->setRenderHints(QPainter::Antialiasing |QPainter::TextAntialiasing);


// draw a circle
painter->drawArc(-width/2,-height/2,width,height,0,16*360);
// draw a smaller circle
painter->drawArc(-10/2,-10/2,10,10,0,16*360);

// change font
QFont font("NanumGothic", 8, QFont::Bold);
painter->setFont(font);
painter->setBrush(QColor(Qt::black));
uint rotationStep = 15;
for(unsigned int i = 0; i < 360; i=i+rotationStep)
{
    if(((i/rotationStep)%3) == 0)
        font.setPointSize(14);
    else
        font.setPointSize(10);
    QFontMetrics fm(font);
    painter->setFont(font);
    QString degreeString;
    degreeString = QString::number(i/(rotationStep*2));

    int pixelsWide = fm.width(degreeString);
    int pixelsHigh = fm.height();
    if((i/rotationStep)%4)
        painter->drawLine(0,-height/2,0, -height/2 + 8);
    else
        painter->drawLine(0,-height/2,0, -height/2 + 14);

    if(((i/rotationStep)%4) == 0)
        painter->drawText(-pixelsWide/2,-height/2 + pixelsHigh + 12,degreeString);

    painter->rotate(rotationStep);
}
painter->translate(0, height/2);

}

QRectF CH::boundingRect() const
{
return QRectF(-width/2,-height/2,width,height);
}

void CH::advance(int phase)
{
objectRotation +=0.1;
setRotation(objectRotation);
}

qreal CH::getWidth()
{
return width;
}

#include <QApplication>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QGraphicsEffect>
#include <QtGui>
#include <QPainter>
#include <QPixmap>
#include <QScreen>
#include <QDebug>

#include "ch.h"

int main(int argc, char *argv[])
{
QApplication a(argc, argv);

QGraphicsScene *scene = new QGraphicsScene;
QGraphicsView *view = new QGraphicsView(scene);
CH *object = new CH(386,386);

// scene setup
scene->addItem(object);
scene->setSceneRect(-view->geometry().width()/2, -view->geometry().height()/2, view->geometry().width(), view->geometry().height());

// view setup
view->setFrameShape(QFrame::NoFrame);
view->setHorizontalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
view->setVerticalScrollBarPolicy(Qt::ScrollBarAlwaysOff);
view->show();

// Timer to start rotation
QTimer *timer = new QTimer;
QObject::connect(timer, SIGNAL(timeout()), scene, SLOT(advance()));
timer->start(100);

return a.exec();

}

@

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[twinding]

Hi all,

Still nobody has answered my question. Is there something wrong with it? Pleeease help. I am new to Qt