levelmeter.h Example File

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#ifndef LEVELMETER_H #define LEVELMETER_H #include <QTime> #include <QWidget> /** * Widget which displays a vertical audio level meter, indicating the * RMS and peak levels of the window of audio samples most recently analyzed * by the Engine. */ class LevelMeter : public QWidget { Q_OBJECT public: explicit LevelMeter(QWidget *parent = 0); ~LevelMeter(); void paintEvent(QPaintEvent *event) override; public slots: void reset(); void levelChanged(qreal rmsLevel, qreal peakLevel, int numSamples); private slots: void redrawTimerExpired(); private: /** * Height of RMS level bar. * Range 0.0 - 1.0. */ qreal m_rmsLevel; /** * Most recent peak level. * Range 0.0 - 1.0. */ qreal m_peakLevel; /** * Height of peak level bar. * This is calculated by decaying m_peakLevel depending on the * elapsed time since m_peakLevelChanged, and the value of m_decayRate. */ qreal m_decayedPeakLevel; /** * Time at which m_peakLevel was last changed. */ QTime m_peakLevelChanged; /** * Rate at which peak level bar decays. * Expressed in level units / millisecond. */ qreal m_peakDecayRate; /** * High watermark of peak level. * Range 0.0 - 1.0. */ qreal m_peakHoldLevel; /** * Time at which m_peakHoldLevel was last changed. */ QTime m_peakHoldLevelChanged; QTimer *m_redrawTimer; QColor m_rmsColor; QColor m_peakColor; }; #endif // LEVELMETER_H

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