spectrograph.h Example File | Qt Multimedia 5.5

- Qt 5.5
- Qt Multimedia
- Spectrum Example
- spectrograph.h Example File
- Qt 5.5.1 Reference Documentation

# spectrograph.h Example File

spectrum/app/spectrograph.h

    /****************************************************************************
    **
    ** Copyright (C) 2015 The Qt Company Ltd.
    ** Contact: http://www.qt.io/licensing/
    **
    ** 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 The Qt Company Ltd 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 SPECTROGRAPH_H
    #define SPECTROGRAPH_H

    #include "frequencyspectrum.h"

    #include <QWidget>

    /**
     * Widget which displays a spectrograph showing the frequency spectrum
     * of the window of audio samples most recently analyzed by the Engine.
     */
    class Spectrograph : public QWidget
    {
        Q_OBJECT

    public:
        explicit Spectrograph(QWidget *parent = 0);
        ~Spectrograph();

        void setParams(int numBars, qreal lowFreq, qreal highFreq);

        // QObject
        void timerEvent(QTimerEvent *event);

        // QWidget
        void paintEvent(QPaintEvent *event);
        void mousePressEvent(QMouseEvent *event);

    signals:
        void infoMessage(const QString &message, int intervalMs);

    public slots:
        void reset();
        void spectrumChanged(const FrequencySpectrum &spectrum);

    private:
        int barIndex(qreal frequency) const;
        QPair<qreal, qreal> barRange(int barIndex) const;
        void updateBars();

        void selectBar(int index);

    private:
        struct Bar {
            Bar() : value(0.0), clipped(false) { }
            qreal   value;
            bool    clipped;
        };

        QVector<Bar>        m_bars;
        int                 m_barSelected;
        int                 m_timerId;
        qreal               m_lowFreq;
        qreal               m_highFreq;
        FrequencySpectrum   m_spectrum;
    };

    #endif // SPECTROGRAPH_H