How to paint object by overriding paintEvent in Qt? - c++

Question

In my QGraphicsView, I have many QGraphicsItem. I want to search specific QGraphicsItem out of all the items present in view and highlight the matched item. For highlighting item, I am trying to use paintEvent.
So I am calling paintEvent, but not understanding how to heighlight border of the matched object ?
Should I need co-ordinates of that matched object ?
I tried like this:
foreach(QGraphicsItem* currentItem, _scene->items())
{
pEvent = false;
QGraphicsRectItem* rItem = qgraphicsitem_cast<QGraphicsRectItem*>(currentItem);
if(rItem)
{
// some logic to get i->Name()
QString name1 = i->Name();
QString name2 = "reN"; // I want to find reN named item in view
if(name1 == name2)
{
pEvent = true;
qDebug()<<"Object Found ";
this->repaint();
break;
}
}
}
void myClass::paintEvent(QPaintEvent *event) {
Q_UNUSED(event);
qDebug()<<"In paint event ";
if(pEvent)
{
QPainter qp(this);
drawBody(&qp);
}
}
void myClass::drawBody(QPainter *qp) {
Q_UNUSED(qp);
// want logic for heighlighting border of the item
}

Answer 1

I understand from your problem that you are overridng QGraphicsView in MyClass since paintEnent is defined QWidgets classes.
To solve your problem, if I understand correctly. It's necessary to save the QGraphicsRectItem coordinates:
QRectF rectF = item.boundingRect();
then use the following in the function drawBody:
qp.save();
const float width = 5;
QPen pen;
pen.setWidth(width );
pen.setColor("green");
painter->drawRect(rectF.x(), rectF().y(),
rectF().width(), rectF().height());
qp.restore();