playercontrols.cpp Example File

  /****************************************************************************
  **
  ** Copyright (C) 2017 The Qt Company Ltd.
  ** Contact: https://www.qt.io/licensing/
  **
  ** This file is part of the examples of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:BSD$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see https://www.qt.io/terms-conditions. For further
  ** information use the contact form at https://www.qt.io/contact-us.
  **
  ** BSD License Usage
  ** Alternatively, 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 "playercontrols.h"

  #include <QBoxLayout>
  #include <QSlider>
  #include <QStyle>
  #include <QToolButton>
  #include <QComboBox>
  #include <QAudio>

  PlayerControls::PlayerControls(QWidget *parent)
      : QWidget(parent)
  {
      m_playButton = new QToolButton(this);
      m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

      connect(m_playButton, &QAbstractButton::clicked, this, &PlayerControls::playClicked);

      m_stopButton = new QToolButton(this);
      m_stopButton->setIcon(style()->standardIcon(QStyle::SP_MediaStop));
      m_stopButton->setEnabled(false);

      connect(m_stopButton, &QAbstractButton::clicked, this, &PlayerControls::stop);

      m_nextButton = new QToolButton(this);
      m_nextButton->setIcon(style()->standardIcon(QStyle::SP_MediaSkipForward));

      connect(m_nextButton, &QAbstractButton::clicked, this, &PlayerControls::next);

      m_previousButton = new QToolButton(this);
      m_previousButton->setIcon(style()->standardIcon(QStyle::SP_MediaSkipBackward));

      connect(m_previousButton, &QAbstractButton::clicked, this, &PlayerControls::previous);

      m_muteButton = new QToolButton(this);
      m_muteButton->setIcon(style()->standardIcon(QStyle::SP_MediaVolume));

      connect(m_muteButton, &QAbstractButton::clicked, this, &PlayerControls::muteClicked);

      m_volumeSlider = new QSlider(Qt::Horizontal, this);
      m_volumeSlider->setRange(0, 100);

      connect(m_volumeSlider, &QSlider::valueChanged, this, &PlayerControls::onVolumeSliderValueChanged);

      m_rateBox = new QComboBox(this);
      m_rateBox->addItem("0.5x", QVariant(0.5));
      m_rateBox->addItem("1.0x", QVariant(1.0));
      m_rateBox->addItem("2.0x", QVariant(2.0));
      m_rateBox->setCurrentIndex(1);

      connect(m_rateBox, QOverload<int>::of(&QComboBox::activated), this, &PlayerControls::updateRate);

      QBoxLayout *layout = new QHBoxLayout;
      layout->setMargin(0);
      layout->addWidget(m_stopButton);
      layout->addWidget(m_previousButton);
      layout->addWidget(m_playButton);
      layout->addWidget(m_nextButton);
      layout->addWidget(m_muteButton);
      layout->addWidget(m_volumeSlider);
      layout->addWidget(m_rateBox);
      setLayout(layout);
  }

  QMediaPlayer::State PlayerControls::state() const
  {
      return m_playerState;
  }

  void PlayerControls::setState(QMediaPlayer::State state)
  {
      if (state != m_playerState) {
          m_playerState = state;

          switch (state) {
          case QMediaPlayer::StoppedState:
              m_stopButton->setEnabled(false);
              m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
              break;
          case QMediaPlayer::PlayingState:
              m_stopButton->setEnabled(true);
              m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPause));
              break;
          case QMediaPlayer::PausedState:
              m_stopButton->setEnabled(true);
              m_playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));
              break;
          }
      }
  }

  int PlayerControls::volume() const
  {
      qreal linearVolume =  QAudio::convertVolume(m_volumeSlider->value() / qreal(100),
                                                  QAudio::LogarithmicVolumeScale,
                                                  QAudio::LinearVolumeScale);

      return qRound(linearVolume * 100);
  }

  void PlayerControls::setVolume(int volume)
  {
      qreal logarithmicVolume = QAudio::convertVolume(volume / qreal(100),
                                                      QAudio::LinearVolumeScale,
                                                      QAudio::LogarithmicVolumeScale);

      m_volumeSlider->setValue(qRound(logarithmicVolume * 100));
  }

  bool PlayerControls::isMuted() const
  {
      return m_playerMuted;
  }

  void PlayerControls::setMuted(bool muted)
  {
      if (muted != m_playerMuted) {
          m_playerMuted = muted;

          m_muteButton->setIcon(style()->standardIcon(muted
                  ? QStyle::SP_MediaVolumeMuted
                  : QStyle::SP_MediaVolume));
      }
  }

  void PlayerControls::playClicked()
  {
      switch (m_playerState) {
      case QMediaPlayer::StoppedState:
      case QMediaPlayer::PausedState:
          emit play();
          break;
      case QMediaPlayer::PlayingState:
          emit pause();
          break;
      }
  }

  void PlayerControls::muteClicked()
  {
      emit changeMuting(!m_playerMuted);
  }

  qreal PlayerControls::playbackRate() const
  {
      return m_rateBox->itemData(m_rateBox->currentIndex()).toDouble();
  }

  void PlayerControls::setPlaybackRate(float rate)
  {
      for (int i = 0; i < m_rateBox->count(); ++i) {
          if (qFuzzyCompare(rate, float(m_rateBox->itemData(i).toDouble()))) {
              m_rateBox->setCurrentIndex(i);
              return;
          }
      }

      m_rateBox->addItem(QString("%1x").arg(rate), QVariant(rate));
      m_rateBox->setCurrentIndex(m_rateBox->count() - 1);
  }

  void PlayerControls::updateRate()
  {
      emit changeRate(playbackRate());
  }

  void PlayerControls::onVolumeSliderValueChanged()
  {
      emit changeVolume(volume());
  }