#include <QApplication>
#include <QStandardItemModel>
#include <QStyledItemDelegate>
#include <QTreeView>

class Delegate : public QStyledItemDelegate
{
public:
    void paint(QPainter *painter, const QStyleOptionViewItem &option, const QModelIndex &index) const
    {
        QStyleOptionViewItem o = option;
        o.font.setBold(true);
        QStyledItemDelegate::paint(painter, o, index);
    }
};

int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    QStandardItemModel model;
    Delegate delegate;
    QStandardItem item("Quite a long string for testing font overriding");
    item.setFont(item.font());
    model.setItem(0, 0, &item);
    QTreeView view;
    view.setItemDelegate(&delegate);
    view.setModel(&model);
    view.show();
    return app.exec();
}