Qt 5.7 | Qt Data Visualization | Audiolevels Example | audiolevels.cpp Example File

Qt 5.7.1 Reference Documentation

# audiolevels.cpp Example File

audiolevels/audiolevels.cpp

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      ** Contact: https://www.qt.io/licensing/
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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();
      }