Qt Reference Documentation

# mainwidget.cpp Example File

demos/spectrum/app/mainwidget.cpp

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     #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)
     {
     #ifdef Q_OS_SYMBIAN
         const QString message = heading + "\n" + detail;
         QMessageBox::warning(this, "", message, QMessageBox::Close);
     #else
         QMessageBox::warning(this, heading, detail, QMessageBox::Close);
     #endif
     }

     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);
     }