audiolevels.cpp Example File

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  ** Contact: https://www.qt.io/licensing/
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  ** This file is part of the Qt Data Visualization module of the Qt Toolkit.
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  #include "audiolevelsiodevice.h"
  #include "audiolevels.h"

  #include <QtDataVisualization/qbardataproxy.h>
  #include <QtDataVisualization/qvalue3daxis.h>
  #include <QtDataVisualization/q3dscene.h>
  #include <QtDataVisualization/q3dcamera.h>
  #include <QtDataVisualization/qbar3dseries.h>
  #include <QtDataVisualization/q3dtheme.h>
  #include <QtDataVisualization/qcustom3dlabel.h>

  #include <QtMultimedia/QAudioDeviceInfo>
  #include <QtMultimedia/QAudioInput>

  using namespace QtDataVisualization;

  AudioLevels::AudioLevels(Q3DBars *graph, QObject *parent)
      : QObject(parent),
        m_graph(graph),
        m_device(0),
        m_audioInput(0)
  {
      // Set up the graph
      m_graph->setBarThickness(0.5f);
      m_graph->setBarSpacing(QSizeF(0.0, 1.0));
      m_graph->valueAxis()->setRange(-100.0f, 100.0f);
      m_graph->valueAxis()->setSegmentCount(20);
      m_graph->valueAxis()->setLabelFormat(QStringLiteral("%d%%"));
      m_graph->setShadowQuality(QAbstract3DGraph::ShadowQualityNone);
      m_graph->setSelectionMode(QAbstract3DGraph::SelectionNone);
      m_graph->scene()->activeCamera()->setCameraPosition(-25.0f, 10.0f, 190.0f);
      m_graph->activeTheme()->setType(Q3DTheme::ThemeIsabelle);
      m_graph->activeTheme()->setGridEnabled(true);
      m_graph->activeTheme()->setBackgroundEnabled(false);
      QFont font = m_graph->activeTheme()->font();
      font.setPointSize(10);
      m_graph->activeTheme()->setFont(font);
      QBar3DSeries *series = new QBar3DSeries;
      series->setMesh(QAbstract3DSeries::MeshBar);
      m_graph->addSeries(series);

      QAudioDeviceInfo inputDevice = QAudioDeviceInfo::defaultInputDevice();

      if (inputDevice.supportedSampleRates().size() > 0
              && inputDevice.supportedChannelCounts().size() > 0
              && inputDevice.supportedSampleSizes().size() > 0
              && inputDevice.supportedCodecs().size() > 0) {
          QAudioFormat formatAudio;
          formatAudio.setSampleRate(inputDevice.supportedSampleRates().at(0));
          formatAudio.setChannelCount(inputDevice.supportedChannelCounts().at(0));
          formatAudio.setSampleSize(inputDevice.supportedSampleSizes().at(0));
          formatAudio.setCodec(inputDevice.supportedCodecs().at(0));
          formatAudio.setByteOrder(QAudioFormat::LittleEndian);
          formatAudio.setSampleType(QAudioFormat::UnSignedInt);

          m_audioInput = new QAudioInput(inputDevice, formatAudio, this);
  #ifdef Q_OS_MAC
          // OS X seems to wait for entire buffer to fill before calling writeData, so use smaller buffer
          m_audioInput->setBufferSize(256);
  #else
          m_audioInput->setBufferSize(1024);
  #endif

          m_device = new AudioLevelsIODevice(m_graph->seriesList().at(0)->dataProxy(), this);
          m_device->open(QIODevice::WriteOnly);

          m_audioInput->start(m_device);
      } else {
          // No graph content can be shown, so add a custom warning label
          QCustom3DLabel *titleLabel = new QCustom3DLabel("No valid audio input device found",
                                                          QFont(),
                                                          QVector3D(0.2f, 0.2f, 0.0f),
                                                          QVector3D(1.0f, 1.0f, 0.0f),
                                                          QQuaternion());
          titleLabel->setPositionAbsolute(true);
          titleLabel->setFacingCamera(true);
          m_graph->addCustomItem(titleLabel);
      }
  }

  AudioLevels::~AudioLevels()
  {
      if (m_audioInput)
          m_audioInput->stop();
      if (m_device)
          m_device->close();
  }