Method updateFromPoint

src/gui/FlexControlDialog.cpp:756–797

    }

    void updateFromPoint(const QPointF& pos)
    {
        const QRectF knob = wheelRect();
        if (!pointerCanAnchor(pos, knob)) {
            m_hasPointerAnchor = false;
            m_pointerClock.restart();
            return;
        }

        const double angle = angleForPoint(pos);
        if (!m_hasPointerAnchor) {
            m_hasPointerAnchor = true;
            m_lastAngle = angle;
            m_pointerClock.restart();
            m_spinClock.restart();
            return;
        }
        const double delta = clampWheelPointerDelta(
            normalizeWheelAngle(angle - m_lastAngle));
        m_lastAngle = angle;
        const double scaledDelta = delta * sensitivityScale();

        const double elapsedMs = std::max<qint64>(m_pointerClock.restart(), 1);
        const double dt = static_cast<double>(elapsedMs) / 1000.0;
        const double instantVelocity = scaledDelta / dt;
        m_stepMultiplier = accelerationForVelocity(instantVelocity);
        applyRotationDelta(scaledDelta, true);

        const double loose = static_cast<double>(m_looseness) / 100.0;
        const double blend = 0.24 + loose * 0.34;
        m_velocity = m_velocity * (1.0 - blend) + instantVelocity * blend;
        m_spinDispatchesSteps = true;
        const bool fastEnoughToCoast =
            std::abs(instantVelocity) >= kWheelCoastStartVelocity
            && std::abs(m_velocity) >= kWheelCoastStartVelocity;
        if (fastEnoughToCoast && !m_spinTimer.isActive()) {
            m_spinClock.restart();
            m_spinTimer.start();
        } else if (!fastEnoughToCoast && m_spinTimer.isActive()) {
            m_spinTimer.stop();
        }
    }

    void tickSpin()
    {