histogramwidget.h Example File

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  #ifndef HISTOGRAMWIDGET_H
  #define HISTOGRAMWIDGET_H

  #include <QThread>
  #include <QVideoFrame>
  #include <QAudioBuffer>
  #include <QWidget>

  class QAudioLevel;

  class FrameProcessor: public QObject
  {
      Q_OBJECT

  public slots:
      void processFrame(QVideoFrame frame, int levels);

  signals:
      void histogramReady(QVector<qreal> histogram);
  };

  class HistogramWidget : public QWidget
  {
      Q_OBJECT

  public:
      explicit HistogramWidget(QWidget *parent = 0);
      ~HistogramWidget();
      void setLevels(int levels) { m_levels = levels; }

  public slots:
      void processFrame(QVideoFrame frame);
      void processBuffer(QAudioBuffer buffer);
      void setHistogram(QVector<qreal> histogram);

  protected:
      void paintEvent(QPaintEvent *event) override;

  private:
      QVector<qreal> m_histogram;
      int m_levels;
      FrameProcessor m_processor;
      QThread m_processorThread;
      bool m_isBusy;
      QVector<QAudioLevel *> audioLevels;
  };

  #endif // HISTOGRAMWIDGET_H