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/****************************************************************************
**
** Copyright (C) 2010 Nokia Corporation and/or its subsidiary(-ies).
** All rights reserved.
** Contact: Nokia Corporation (qt-info@nokia.com)
**
** This file is part of the examples of the Qt Toolkit.
**
** $QT_BEGIN_LICENSE:BSD$
** You may use this file under the terms of the BSD license as follows:
**
** "Redistribution and use in source and binary forms, with or without
** modification, are permitted provided that the following conditions are
** met:
** * Redistributions of source code must retain the above copyright
** notice, this list of conditions and the following disclaimer.
** * Redistributions in binary form must reproduce the above copyright
** notice, this list of conditions and the following disclaimer in
** the documentation and/or other materials provided with the
** distribution.
** * Neither the name of Nokia Corporation and its Subsidiary(-ies) nor
** the names of its contributors may be used to endorse or promote
** products derived from this software without specific prior written
** permission.
**
** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
** $QT_END_LICENSE$
**
****************************************************************************/
#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 analysed
* by the Engine.
*/
class LevelMeter : public QWidget {
Q_OBJECT
public:
LevelMeter(QWidget *parent = 0);
~LevelMeter();
void paintEvent(QPaintEvent *event);
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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