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| |
| #include "levelmeter.h" |
| |
| #include <math.h> |
| |
| #include <QPainter> |
| #include <QTimer> |
| #include <QDebug> |
| |
| |
| // Constants |
| const int RedrawInterval = 100; // ms |
| const qreal PeakDecayRate = 0.001; |
| const int PeakHoldLevelDuration = 2000; // ms |
| |
| |
| LevelMeter::LevelMeter(QWidget *parent) |
| : QWidget(parent) |
| , m_rmsLevel(0.0) |
| , m_peakLevel(0.0) |
| , m_decayedPeakLevel(0.0) |
| , m_peakDecayRate(PeakDecayRate) |
| , m_peakHoldLevel(0.0) |
| , m_redrawTimer(new QTimer(this)) |
| , m_rmsColor(Qt::red) |
| , m_peakColor(255, 200, 200, 255) |
| { |
| setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Preferred); |
| setMinimumWidth(30); |
| |
| connect(m_redrawTimer, &QTimer::timeout, |
| this, &LevelMeter::redrawTimerExpired); |
| m_redrawTimer->start(RedrawInterval); |
| } |
| |
| LevelMeter::~LevelMeter() |
| { |
| |
| } |
| |
| void LevelMeter::reset() |
| { |
| m_rmsLevel = 0.0; |
| m_peakLevel = 0.0; |
| update(); |
| } |
| |
| void LevelMeter::levelChanged(qreal rmsLevel, qreal peakLevel, int numSamples) |
| { |
| // Smooth the RMS signal |
| const qreal smooth = pow(qreal(0.9), static_cast<qreal>(numSamples) / 256); // TODO: remove this magic number |
| m_rmsLevel = (m_rmsLevel * smooth) + (rmsLevel * (1.0 - smooth)); |
| |
| if (peakLevel > m_decayedPeakLevel) { |
| m_peakLevel = peakLevel; |
| m_decayedPeakLevel = peakLevel; |
| m_peakLevelChanged.start(); |
| } |
| |
| if (peakLevel > m_peakHoldLevel) { |
| m_peakHoldLevel = peakLevel; |
| m_peakHoldLevelChanged.start(); |
| } |
| |
| update(); |
| } |
| |
| void LevelMeter::redrawTimerExpired() |
| { |
| // Decay the peak signal |
| const int elapsedMs = m_peakLevelChanged.elapsed(); |
| const qreal decayAmount = m_peakDecayRate * elapsedMs; |
| if (decayAmount < m_peakLevel) |
| m_decayedPeakLevel = m_peakLevel - decayAmount; |
| else |
| m_decayedPeakLevel = 0.0; |
| |
| // Check whether to clear the peak hold level |
| if (m_peakHoldLevelChanged.elapsed() > PeakHoldLevelDuration) |
| m_peakHoldLevel = 0.0; |
| |
| update(); |
| } |
| |
| void LevelMeter::paintEvent(QPaintEvent *event) |
| { |
| Q_UNUSED(event) |
| |
| QPainter painter(this); |
| painter.fillRect(rect(), Qt::black); |
| |
| QRect bar = rect(); |
| |
| bar.setTop(rect().top() + (1.0 - m_peakHoldLevel) * rect().height()); |
| bar.setBottom(bar.top() + 5); |
| painter.fillRect(bar, m_rmsColor); |
| bar.setBottom(rect().bottom()); |
| |
| bar.setTop(rect().top() + (1.0 - m_decayedPeakLevel) * rect().height()); |
| painter.fillRect(bar, m_peakColor); |
| |
| bar.setTop(rect().top() + (1.0 - m_rmsLevel) * rect().height()); |
| painter.fillRect(bar, m_rmsColor); |
| } |