Рисование точек по координатам

Ring::Ring( QWidget *parent ) :
    QWidget( parent )
{
    dot_1 =1;
    dot_2 =1;
    dot_3 =1;
 
    // Устанавливаем кодеки
    QTextCodec::setCodecForCStrings( QTextCodec::codecForName( "UTF-8" ) );
    QTextCodec::setCodecForTr( QTextCodec::codecForName( "UTF-8" ) );
 
    resize(300, 300);
}
 
void Ring::paintEvent(QPaintEvent *){
 
 int side = qMin(width(), height());
 
 QPainter painter(this);
 painter.setRenderHint(QPainter::Antialiasing);
 painter.translate(width() / 2, height() / 2);
 painter.scale(side / 300.0, side / 300.0);
 
 painter.setPen(Qt::NoPen);
 painter.save();
 
 painter.restore();
 
 painter.setPen(QPen(Qt::black,1,Qt::SolidLine));
 painter.drawEllipse(-50,-50,100,100);
 
 painter.setPen(QPen(Qt::black,1,Qt::SolidLine));
 painter.drawEllipse(-100,-100,200,200);
 
 painter.setPen(QPen(Qt::black,1,Qt::SolidLine));
 painter.drawEllipse(-150,-150,300,300);
 
 painter.drawLine(0,150,0,-150);
 painter.drawLine(-150,0,150,0);
 
 painter.setPen(QPen(Qt::black,2,Qt::SolidLine));
 painter.drawPoint(dot_1,dot_2);
 
 
}

#include <QWidget>
 
class Ring : public QWidget
{
    Q_OBJECT
public:
    Ring( QWidget *parent = 0 );
 
    void setDot(int x, int y, int signal )
    {
        dot_1 = x;
        dot_2 = y;
        dot_3 = signal;
 
        //update();
    }
 
private:
 
int dot_1, dot_2, dot_3;
 
signals:
 
protected:
     void paintEvent( QPaintEvent *event );
    
public slots:
    
};

MyPoint { int x,y,z };
 
void Main(){
QVector<MyPoint> points;
MyPoint point;
point.x = 1;
point.y = 1;
point.z = 2;
points.push_back(point); // points: {1,1,2}
point.y = 2;
points.push_back(point); // points: {1,1,2}, {1,2,2}
qDebug() << points[0].x << points[0].y; // 1 1
}

Ring::~Ring()
{
    qDeleteAll(pv);
}

 
class Ring { 
  Ring::Ring(QVector<MyPoint*> * p = Q_NULLPTR);
  /*...*/ 
  QVector<MyPoint*> * points;
  /*...*/};
 
Ring::Ring(QVector<MyPoint*> * p)
  : points(p) {/*...*/}
 
void Ring::paintEvent(...)
{
  if (points)
  {
    foreach(MyPoint *p, *pv)
      painter.drawPoint(p->x,p->y);
 
  }
}
 
class MainWidget { /*...*/ QVector<MyPoint*> points; /*...*/ };
 
MainWidget::MainWidget()
  : Ring(&points) {}