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// Copyright (C) 2017 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#ifndef LEVELMETER_H
#define LEVELMETER_H
#include <QElapsedTimer>
#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.
*/
QElapsedTimer 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.
*/
QElapsedTimer m_peakHoldLevelChanged;
QTimer *m_redrawTimer;
QColor m_rmsColor;
QColor m_peakColor;
};
#endif // LEVELMETER_H
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