Method drawEnvelope

src/gui/StripWaveform.cpp:523–618

}

void StripWaveform::drawEnvelope(QPainter& painter,
                                  const QRectF& plotRect,
                                  int clipCount)
{
    const int columnCount = std::max(1, static_cast<int>(std::floor(plotRect.width())));
    buildColumns(columnCount);
    if (m_columns.isEmpty())
        return;

    const qreal centerY = plotRect.center().y();
    const qreal halfHeight = std::max<qreal>(1.0, plotRect.height() * 0.5 - 2.0);
    const qreal left = plotRect.left();
    const QColor wave = waveformColor();

    QVector<QPointF> rmsTop;
    QVector<QPointF> rmsBottom;
    QPainterPath peakTop;
    QPainterPath peakBottom;
    QPainterPath rmsLineTop;
    QPainterPath rmsLineBottom;

    rmsTop.reserve(m_columns.size());
    rmsBottom.reserve(m_columns.size());

    for (int x = 0; x < m_columns.size(); ++x) {
        const ColumnStats& c = m_columns[x];
        const qreal px = left + x + 0.5;
        const qreal peak = std::clamp(c.peak * m_amplitudeZoom, 0.0f, 1.0f);
        const qreal rms = std::clamp(c.rms * m_amplitudeZoom, 0.0f, 1.0f);
        const qreal peakTopY = centerY - peak * halfHeight;
        const qreal peakBottomY = centerY + peak * halfHeight;
        const qreal rmsTopY = centerY - rms * halfHeight;
        const qreal rmsBottomY = centerY + rms * halfHeight;

        rmsTop.append(QPointF(px, rmsTopY));
        rmsBottom.append(QPointF(px, rmsBottomY));

        if (x == 0) {
            peakTop.moveTo(px, peakTopY);
            peakBottom.moveTo(px, peakBottomY);
            rmsLineTop.moveTo(px, rmsTopY);
            rmsLineBottom.moveTo(px, rmsBottomY);
        } else {
            peakTop.lineTo(px, peakTopY);
            peakBottom.lineTo(px, peakBottomY);
            rmsLineTop.lineTo(px, rmsTopY);
            rmsLineBottom.lineTo(px, rmsBottomY);
        }
    }

    QPainterPath fillPath;
    fillPath.moveTo(rmsTop.first());
    for (int i = 1; i < rmsTop.size(); ++i)
        fillPath.lineTo(rmsTop[i]);
    for (int i = rmsBottom.size() - 1; i >= 0; --i)
        fillPath.lineTo(rmsBottom[i]);
    fillPath.closeSubpath();