Method eventFilter

plugins/wlcompositorinspector/logview.cpp:551–572

    }

    bool eventFilter(QObject *o, QEvent *e) override
    {
        if (o == &m_view && e->type() == QEvent::Wheel) {
            QWheelEvent *we = static_cast<QWheelEvent *>(e);

            qreal pos = we->position().x() * m_view.m_zoom;
            auto sb = horizontalScrollBar();
            int sbvalue = horizontalScrollBar()->value();

            m_view.m_zoom += (1. - qPow(5. / 4., qreal(we->angleDelta().y()) / 150.)) * m_view.m_zoom;
            if (m_view.m_zoom < 10) {
                m_view.m_zoom = 10;
            }

            m_view.updateSize();

            // keep the point under the mouse still, if possible
            pos = pos / m_view.m_zoom;
            sb->setValue(sbvalue + (0.5 + pos - we->position().x()));
        }
        return QScrollArea::eventFilter(o, e);
    }

    View m_view;
};