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Diffstat (limited to 'examples/multimedia/spectrum/app/levelmeter.h')
-rw-r--r-- | examples/multimedia/spectrum/app/levelmeter.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/examples/multimedia/spectrum/app/levelmeter.h b/examples/multimedia/spectrum/app/levelmeter.h new file mode 100644 index 000000000..53147ff7b --- /dev/null +++ b/examples/multimedia/spectrum/app/levelmeter.h @@ -0,0 +1,118 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** 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 Digia Plc 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 analyzed + * by the Engine. + */ +class LevelMeter : public QWidget +{ + Q_OBJECT + +public: + explicit 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 |