Russian Qt Forum

class TabBarButton : public QAbstractButton
{
public:
    TabBarButton() :
        QAbstractButton(),
        hovered(false),
        pressed(false)
    {
    }

    void paintEvent(QPaintEvent *e)
    {
        QPainter p(this);

        QStyleOptionTabBarBaseV2 opt;
        opt.init(this);
        // hardcoded document Mode
        opt.documentMode = true;

        int overlap = style()->pixelMetric(QStyle::PM_TabBarBaseOverlap, &opt, this);
        QRect rect;
        // hardcoded north position
        rect.setRect(0, size().height() - overlap, size().width(), overlap);
        opt.rect = rect;

        qApp->style()->drawPrimitive(QStyle::PE_FrameTabBarBase, &opt, &p, this);

        int w = iconSize().width();
        int h = iconSize().height();
        QIcon::Mode mode = pressed ? QIcon::Selected : QIcon::Normal;

        icon().paint(&p, (width() - w)/2, (height() - h)/2, w, h, Qt::AlignCenter, mode);
    }

    QSize sizeHint() const { return iconSize(); }
    void enterEvent(QEvent *) { hovered = true; update(); }
    void leaveEvent(QEvent *) { hovered = false; update(); }
    void mousePressEvent(QMouseEvent *e) { pressed = true; update(); QAbstractButton::mousePressEvent(e); }
    void mouseReleaseEvent(QMouseEvent *e) { pressed = false; update(); QAbstractButton::mouseReleaseEvent(e); }

private:
    bool hovered;
    bool pressed;
};

{
...
    newTabButton = new TabBarButton();
    newTabButton->setIcon(QIcon(":/images/icons/addtab.png"));
    newTabButton->setIconSize(QSize(32,32));
    connect(newTabButton, SIGNAL(clicked()), q, SLOT(newTab()));

    tabWidget = new MyTabWidget;
    tabWidget->setDocumentMode(true);
    tabWidget->setMovable(true);
    tabWidget->setTabsClosable(true);
    tabWidget->setUsesScrollButtons(true);
    tabWidget->setCornerWidget(newTabButton);

    q->setCentralWidget(tabWidget);

    connect(tabWidget, SIGNAL(currentChanged(int)), this, SLOT(onCurrentChanged(int)));
    connect(tabWidget, SIGNAL(tabCloseRequested(int)), q, SLOT(closeTab(int)));
    connect(tabWidget, SIGNAL(tabBarDoubleClicked()), q, SLOT(newTab()));
...
}