Qt 5.6 | Qt Multimedia | Spectrum Example | spectrograph.h Example File

Qt 5.6.3 Reference Documentation

# spectrograph.h Example File

multimedia/spectrum/app/spectrograph.h

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      #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