Qt 5.6 | Qt Multimedia | Spectrum Example | mainwidget.cpp Example File

Qt 5.6.2 Reference Documentation

# mainwidget.cpp Example File

multimedia/spectrum/app/mainwidget.cpp

      /****************************************************************************
      **
      ** 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."
      **
      ** $QT_END_LICENSE$
      **
      ****************************************************************************/

      #include "engine.h"
      #include "levelmeter.h"
      #include "mainwidget.h"
      #include "waveform.h"
      #include "progressbar.h"
      #include "settingsdialog.h"
      #include "spectrograph.h"
      #include "tonegeneratordialog.h"
      #include "utils.h"

      #include <QLabel>
      #include <QPushButton>
      #include <QHBoxLayout>
      #include <QVBoxLayout>
      #include <QStyle>
      #include <QMenu>
      #include <QFileDialog>
      #include <QTimerEvent>
      #include <QMessageBox>

      const int NullTimerId = -1;

      MainWidget::MainWidget(QWidget *parent)
          :   QWidget(parent)
          ,   m_mode(NoMode)
          ,   m_engine(new Engine(this))
      #ifndef DISABLE_WAVEFORM
          ,   m_waveform(new Waveform(this))
      #endif
          ,   m_progressBar(new ProgressBar(this))
          ,   m_spectrograph(new Spectrograph(this))
          ,   m_levelMeter(new LevelMeter(this))
          ,   m_modeButton(new QPushButton(this))
          ,   m_recordButton(new QPushButton(this))
          ,   m_pauseButton(new QPushButton(this))
          ,   m_playButton(new QPushButton(this))
          ,   m_settingsButton(new QPushButton(this))
          ,   m_infoMessage(new QLabel(tr("Select a mode to begin"), this))
          ,   m_infoMessageTimerId(NullTimerId)
          ,   m_settingsDialog(new SettingsDialog(
                  m_engine->availableAudioInputDevices(),
                  m_engine->availableAudioOutputDevices(),
                  this))
          ,   m_toneGeneratorDialog(new ToneGeneratorDialog(this))
          ,   m_modeMenu(new QMenu(this))
          ,   m_loadFileAction(0)
          ,   m_generateToneAction(0)
          ,   m_recordAction(0)
      {
          m_spectrograph->setParams(SpectrumNumBands, SpectrumLowFreq, SpectrumHighFreq);

          createUi();
          connectUi();
      }

      MainWidget::~MainWidget()
      {

      }

      //-----------------------------------------------------------------------------
      // Public slots
      //-----------------------------------------------------------------------------

      void MainWidget::stateChanged(QAudio::Mode mode, QAudio::State state)
      {
          Q_UNUSED(mode);

          updateButtonStates();

          if (QAudio::ActiveState != state && QAudio::SuspendedState != state) {
              m_levelMeter->reset();
              m_spectrograph->reset();
          }
      }

      void MainWidget::formatChanged(const QAudioFormat &format)
      {
         infoMessage(formatToString(format), NullMessageTimeout);

      #ifndef DISABLE_WAVEFORM
          if (QAudioFormat() != format) {
              m_waveform->initialize(format, WaveformTileLength,
                                     WaveformWindowDuration);
          }
      #endif
      }

      void MainWidget::spectrumChanged(qint64 position, qint64 length,
                                       const FrequencySpectrum &spectrum)
      {
          m_progressBar->windowChanged(position, length);
          m_spectrograph->spectrumChanged(spectrum);
      }

      void MainWidget::infoMessage(const QString &message, int timeoutMs)
      {
          m_infoMessage->setText(message);

          if (NullTimerId != m_infoMessageTimerId) {
              killTimer(m_infoMessageTimerId);
              m_infoMessageTimerId = NullTimerId;
          }

          if (NullMessageTimeout != timeoutMs)
              m_infoMessageTimerId = startTimer(timeoutMs);
      }

      void MainWidget::errorMessage(const QString &heading, const QString &detail)
      {
          QMessageBox::warning(this, heading, detail, QMessageBox::Close);
      }

      void MainWidget::timerEvent(QTimerEvent *event)
      {
          Q_ASSERT(event->timerId() == m_infoMessageTimerId);
          Q_UNUSED(event) // suppress warnings in release builds
          killTimer(m_infoMessageTimerId);
          m_infoMessageTimerId = NullTimerId;
          m_infoMessage->setText("");
      }

      void MainWidget::audioPositionChanged(qint64 position)
      {
      #ifndef DISABLE_WAVEFORM
          m_waveform->audioPositionChanged(position);
      #else
          Q_UNUSED(position)
      #endif
      }

      void MainWidget::bufferLengthChanged(qint64 length)
      {
          m_progressBar->bufferLengthChanged(length);
      }

      //-----------------------------------------------------------------------------
      // Private slots
      //-----------------------------------------------------------------------------

      void MainWidget::showFileDialog()
      {
          const QString dir;
          const QStringList fileNames = QFileDialog::getOpenFileNames(this, tr("Open WAV file"), dir, "*.wav");
          if (fileNames.count()) {
              reset();
              setMode(LoadFileMode);
              m_engine->loadFile(fileNames.front());
              updateButtonStates();
          } else {
              updateModeMenu();
          }
      }

      void MainWidget::showSettingsDialog()
      {
          m_settingsDialog->exec();
          if (m_settingsDialog->result() == QDialog::Accepted) {
              m_engine->setAudioInputDevice(m_settingsDialog->inputDevice());
              m_engine->setAudioOutputDevice(m_settingsDialog->outputDevice());
              m_engine->setWindowFunction(m_settingsDialog->windowFunction());
          }
      }

      void MainWidget::showToneGeneratorDialog()
      {
          m_toneGeneratorDialog->exec();
          if (m_toneGeneratorDialog->result() == QDialog::Accepted) {
              reset();
              setMode(GenerateToneMode);
              const qreal amplitude = m_toneGeneratorDialog->amplitude();
              if (m_toneGeneratorDialog->isFrequencySweepEnabled()) {
                  m_engine->generateSweptTone(amplitude);
              } else {
                  const qreal frequency = m_toneGeneratorDialog->frequency();
                  const Tone tone(frequency, amplitude);
                  m_engine->generateTone(tone);
                  updateButtonStates();
              }
          } else {
              updateModeMenu();
          }
      }

      void MainWidget::initializeRecord()
      {
          reset();
          setMode(RecordMode);
          if (m_engine->initializeRecord())
              updateButtonStates();
      }

      //-----------------------------------------------------------------------------
      // Private functions
      //-----------------------------------------------------------------------------

      void MainWidget::createUi()
      {
          createMenus();

          setWindowTitle(tr("Spectrum Analyser"));

          QVBoxLayout *windowLayout = new QVBoxLayout(this);

          m_infoMessage->setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);
          m_infoMessage->setAlignment(Qt::AlignHCenter);
          windowLayout->addWidget(m_infoMessage);

      #ifdef SUPERIMPOSE_PROGRESS_ON_WAVEFORM
          QScopedPointer<QHBoxLayout> waveformLayout(new QHBoxLayout);
          waveformLayout->addWidget(m_progressBar);
          m_progressBar->setMinimumHeight(m_waveform->minimumHeight());
          waveformLayout->setMargin(0);
          m_waveform->setLayout(waveformLayout.data());
          waveformLayout.take();
          windowLayout->addWidget(m_waveform);
      #else
      #ifndef DISABLE_WAVEFORM
          windowLayout->addWidget(m_waveform);
      #endif // DISABLE_WAVEFORM
          windowLayout->addWidget(m_progressBar);
      #endif // SUPERIMPOSE_PROGRESS_ON_WAVEFORM

          // Spectrograph and level meter

          QScopedPointer<QHBoxLayout> analysisLayout(new QHBoxLayout);
          analysisLayout->addWidget(m_spectrograph);
          analysisLayout->addWidget(m_levelMeter);
          windowLayout->addLayout(analysisLayout.data());
          analysisLayout.take();

          // Button panel

          const QSize buttonSize(30, 30);

          m_modeButton->setText(tr("Mode"));

          m_recordIcon = QIcon(":/images/record.png");
          m_recordButton->setIcon(m_recordIcon);
          m_recordButton->setEnabled(false);
          m_recordButton->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
          m_recordButton->setMinimumSize(buttonSize);

          m_pauseIcon = style()->standardIcon(QStyle::SP_MediaPause);
          m_pauseButton->setIcon(m_pauseIcon);
          m_pauseButton->setEnabled(false);
          m_pauseButton->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
          m_pauseButton->setMinimumSize(buttonSize);

          m_playIcon = style()->standardIcon(QStyle::SP_MediaPlay);
          m_playButton->setIcon(m_playIcon);
          m_playButton->setEnabled(false);
          m_playButton->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
          m_playButton->setMinimumSize(buttonSize);

          m_settingsIcon = QIcon(":/images/settings.png");
          m_settingsButton->setIcon(m_settingsIcon);
          m_settingsButton->setEnabled(true);
          m_settingsButton->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
          m_settingsButton->setMinimumSize(buttonSize);

          QScopedPointer<QHBoxLayout> buttonPanelLayout(new QHBoxLayout);
          buttonPanelLayout->addStretch();
          buttonPanelLayout->addWidget(m_modeButton);
          buttonPanelLayout->addWidget(m_recordButton);
          buttonPanelLayout->addWidget(m_pauseButton);
          buttonPanelLayout->addWidget(m_playButton);
          buttonPanelLayout->addWidget(m_settingsButton);

          QWidget *buttonPanel = new QWidget(this);
          buttonPanel->setSizePolicy(QSizePolicy::Fixed, QSizePolicy::Fixed);
          buttonPanel->setLayout(buttonPanelLayout.data());
          buttonPanelLayout.take(); // ownership transferred to buttonPanel

          QScopedPointer<QHBoxLayout> bottomPaneLayout(new QHBoxLayout);
          bottomPaneLayout->addWidget(buttonPanel);
          windowLayout->addLayout(bottomPaneLayout.data());
          bottomPaneLayout.take(); // ownership transferred to windowLayout

          // Apply layout

          setLayout(windowLayout);
      }

      void MainWidget::connectUi()
      {
          CHECKED_CONNECT(m_recordButton, SIGNAL(clicked()),
                  m_engine, SLOT(startRecording()));

          CHECKED_CONNECT(m_pauseButton, SIGNAL(clicked()),
                  m_engine, SLOT(suspend()));

          CHECKED_CONNECT(m_playButton, SIGNAL(clicked()),
                  m_engine, SLOT(startPlayback()));

          CHECKED_CONNECT(m_settingsButton, SIGNAL(clicked()),
                  this, SLOT(showSettingsDialog()));

          CHECKED_CONNECT(m_engine, SIGNAL(stateChanged(QAudio::Mode,QAudio::State)),
                  this, SLOT(stateChanged(QAudio::Mode,QAudio::State)));

          CHECKED_CONNECT(m_engine, SIGNAL(formatChanged(const QAudioFormat &)),
                  this, SLOT(formatChanged(const QAudioFormat &)));

          m_progressBar->bufferLengthChanged(m_engine->bufferLength());

          CHECKED_CONNECT(m_engine, SIGNAL(bufferLengthChanged(qint64)),
                  this, SLOT(bufferLengthChanged(qint64)));

          CHECKED_CONNECT(m_engine, SIGNAL(dataLengthChanged(qint64)),
                  this, SLOT(updateButtonStates()));

          CHECKED_CONNECT(m_engine, SIGNAL(recordPositionChanged(qint64)),
                  m_progressBar, SLOT(recordPositionChanged(qint64)));

          CHECKED_CONNECT(m_engine, SIGNAL(playPositionChanged(qint64)),
                  m_progressBar, SLOT(playPositionChanged(qint64)));

          CHECKED_CONNECT(m_engine, SIGNAL(recordPositionChanged(qint64)),
                  this, SLOT(audioPositionChanged(qint64)));

          CHECKED_CONNECT(m_engine, SIGNAL(playPositionChanged(qint64)),
                  this, SLOT(audioPositionChanged(qint64)));

          CHECKED_CONNECT(m_engine, SIGNAL(levelChanged(qreal, qreal, int)),
                  m_levelMeter, SLOT(levelChanged(qreal, qreal, int)));

          CHECKED_CONNECT(m_engine, SIGNAL(spectrumChanged(qint64, qint64, const FrequencySpectrum &)),
                  this, SLOT(spectrumChanged(qint64, qint64, const FrequencySpectrum &)));

          CHECKED_CONNECT(m_engine, SIGNAL(infoMessage(QString, int)),
                  this, SLOT(infoMessage(QString, int)));

          CHECKED_CONNECT(m_engine, SIGNAL(errorMessage(QString, QString)),
                  this, SLOT(errorMessage(QString, QString)));

          CHECKED_CONNECT(m_spectrograph, SIGNAL(infoMessage(QString, int)),
                  this, SLOT(infoMessage(QString, int)));

      #ifndef DISABLE_WAVEFORM
          CHECKED_CONNECT(m_engine, SIGNAL(bufferChanged(qint64, qint64, const QByteArray &)),
                  m_waveform, SLOT(bufferChanged(qint64, qint64, const QByteArray &)));
      #endif
      }

      void MainWidget::createMenus()
      {
          m_modeButton->setMenu(m_modeMenu);

          m_generateToneAction = m_modeMenu->addAction(tr("Play generated tone"));
          m_recordAction = m_modeMenu->addAction(tr("Record and play back"));
          m_loadFileAction = m_modeMenu->addAction(tr("Play file"));

          m_loadFileAction->setCheckable(true);
          m_generateToneAction->setCheckable(true);
          m_recordAction->setCheckable(true);

          connect(m_loadFileAction, SIGNAL(triggered(bool)), this, SLOT(showFileDialog()));
          connect(m_generateToneAction, SIGNAL(triggered(bool)), this, SLOT(showToneGeneratorDialog()));
          connect(m_recordAction, SIGNAL(triggered(bool)), this, SLOT(initializeRecord()));
      }

      void MainWidget::updateButtonStates()
      {
          const bool recordEnabled = ((QAudio::AudioOutput == m_engine->mode() ||
                                      (QAudio::ActiveState != m_engine->state() &&
                                       QAudio::IdleState != m_engine->state())) &&
                                      RecordMode == m_mode);
          m_recordButton->setEnabled(recordEnabled);

          const bool pauseEnabled = (QAudio::ActiveState == m_engine->state() ||
                                     QAudio::IdleState == m_engine->state());
          m_pauseButton->setEnabled(pauseEnabled);

          const bool playEnabled = (/*m_engine->dataLength() &&*/
                                    (QAudio::AudioOutput != m_engine->mode() ||
                                     (QAudio::ActiveState != m_engine->state() &&
                                      QAudio::IdleState != m_engine->state())));
          m_playButton->setEnabled(playEnabled);
      }

      void MainWidget::reset()
      {
      #ifndef DISABLE_WAVEFORM
          m_waveform->reset();
      #endif
          m_engine->reset();
          m_levelMeter->reset();
          m_spectrograph->reset();
          m_progressBar->reset();
      }

      void MainWidget::setMode(Mode mode)
      {
          m_mode = mode;
          updateModeMenu();
      }

      void MainWidget::updateModeMenu()
      {
          m_loadFileAction->setChecked(LoadFileMode == m_mode);
          m_generateToneAction->setChecked(GenerateToneMode == m_mode);
          m_recordAction->setChecked(RecordMode == m_mode);
      }