Method paintEvent

src/gui/ClientDeEssCurveWidget.cpp:118–221

}

void ClientDeEssCurveWidget::paintEvent(QPaintEvent*)
{
    QPainter p(this);
    p.setRenderHint(QPainter::Antialiasing, true);

    const QRectF r = rect();
    p.fillRect(r, kBgColor());

    // Grid — vertical at major freqs, horizontal at 0 / -12 / -24.
    p.save();
    p.setPen(QPen(kGridColor(), 1.0));
    for (float db : { 0.0f, -12.0f, -24.0f }) {
        const float y = dbToY(db);
        p.drawLine(QPointF(r.left(), y), QPointF(r.right(), y));
    }
    p.setPen(QPen(kGridMajorColor(), 1.0));
    QFont font = p.font();
    font.setPixelSize(8);
    p.setFont(font);

    // Build the QStaticText cache once — font is fixed at 8 px regardless
    // of compact mode, so this set never needs invalidation after the
    // first paint.  Labels follow kFreqMajor: "100", "500", "1k", etc.
    if (m_labelsDirty) {
        m_axisLabels.clear();
        m_axisLabels.reserve(static_cast<int>(std::size(kFreqMajor)));
        for (float f : kFreqMajor) {
            const QString lbl = (f >= 1000.0f)
                ? QString::number(int(f / 1000.0f)) + "k"
                : QString::number(int(f));
            QStaticText st(lbl);
            st.setPerformanceHint(QStaticText::AggressiveCaching);
            m_axisLabels.append(std::move(st));
        }
        m_labelsDirty = false;
    }

    // drawStaticText anchors at top-left, drawText at the baseline —
    // subtract ascent so the visual position matches the prior render.
    const qreal ascent = p.fontMetrics().ascent();

    for (size_t i = 0; i < std::size(kFreqMajor); ++i) {
        const float f = kFreqMajor[i];
        const float x = hzToX(f);
        p.drawLine(QPointF(x, r.top()), QPointF(x, r.bottom()));
        if (!m_compact) {
            m_axisLabels[i].prepare(p.transform(), font);
            p.setPen(kAxisLabelColor());
            p.drawStaticText(QPointF(x + 2.0f, r.bottom() - 2.0f - ascent),
                             m_axisLabels[i]);
            p.setPen(QPen(kGridMajorColor(), 1.0));
        }
    }
    p.restore();

    // Bandpass magnitude curve.
    if (m_deEss) {
        QPainterPath path;