How to remove this effect?

deleted385

When I hover over the items, the top line becomes thinner or is restored to original style like this:

The code is almost same as this, I've added a UserRole for those Total. In the Delegate, I've these:

Delegate::Delegate(){ }
void Delegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const{   
    painter->setRenderHints(QPainter::Antialiasing|QPainter::TextAntialiasing);
    QStyledItemDelegate::paint(painter, option, index);
    if(index.siblingAtColumn(0).data(Qt::UserRole) == "Aggregate" && index.column() > 0){
        painter->drawLine(option.rect.topLeft(), option.rect.topRight());
        painter->drawLine(option.rect.bottomLeft(), option.rect.bottomRight());
    }
}

raven-worx

@Emon-Haque
your line overlaps indexes and i guess you used a (default) pen with a width of 2px.
So the half of the line is overdrawn when the index/row is repainted without the highlighting.

you need to translate the line by the half of the line/pen width to ensure that it is inside the index boundaries.

deleted385

@raven-worx, this translation works:

void Delegate::paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const{   
    painter->setRenderHints(QPainter::Antialiasing|QPainter::TextAntialiasing);
    QStyledItemDelegate::paint(painter, option, index);
    if(index.siblingAtColumn(0).data(Qt::UserRole) == "Aggregate" && index.column() > 0){
        painter->save();
        painter->translate(0,1);
        painter->drawLine(option.rect.topLeft(), option.rect.topRight());
        painter->restore();
        painter->drawLine(option.rect.bottomLeft(), option.rect.bottomRight());
    }
}

Is there an extra 1 px/pt gap at the end of last child of each node or at the end of each Total?

raven-worx

@Emon-Haque
just a tip:

QPainter save/restore is rather costly and should be avoided if you are after performance. Better just translate the line coordiantes
the generic way would be to calculate the translation based on the pen width: int translate = qCeil(painter->pen().width() * 0.5)

Is there an extra 1 px/pt gap at the end of last child of each node or at the end of each Total?

i dont understand your question

deleted385

@raven-worx, the top line is now 1 px/pt below the original position so there's an extra 1px/pt gap between those top lines and last Some Text -1,000 1000 of each node, right? And all those Total 1,000 1000 is 1 px/pt closer to the top line.

raven-worx

@Emon-Haque
i dont see an additional gap.
you may want to read this: https://doc.qt.io/qt-5/coordsys.html