playercontrols.cpp Example File | Qt Multimedia 5.9

Qt 5.9 | Qt Multimedia | Media Player Example | playercontrols.cpp Example File

Qt 5.9.9 Reference Documentation

# playercontrols.cpp Example File

multimediawidgets/player/playercontrols.cpp

      /****************************************************************************
      **
      ** 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)
          , playerState(QMediaPlayer::StoppedState)
          , playerMuted(false)
          , playButton(0)
          , stopButton(0)
          , nextButton(0)
          , previousButton(0)
          , muteButton(0)
          , volumeSlider(0)
          , rateBox(0)
      {
          playButton = new QToolButton(this);
          playButton->setIcon(style()->standardIcon(QStyle::SP_MediaPlay));

          connect(playButton, SIGNAL(clicked()), this, SLOT(playClicked()));

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

          connect(stopButton, SIGNAL(clicked()), this, SIGNAL(stop()));

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

          connect(nextButton, SIGNAL(clicked()), this, SIGNAL(next()));

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

          connect(previousButton, SIGNAL(clicked()), this, SIGNAL(previous()));

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

          connect(muteButton, SIGNAL(clicked()), this, SLOT(muteClicked()));

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

          connect(volumeSlider, SIGNAL(valueChanged(int)), this, SLOT(onVolumeSliderValueChanged()));

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

          connect(rateBox, SIGNAL(activated(int)), SLOT(updateRate()));

          QBoxLayout *layout = new QHBoxLayout;
          layout->setMargin(0);
          layout->addWidget(stopButton);
          layout->addWidget(previousButton);
          layout->addWidget(playButton);
          layout->addWidget(nextButton);
          layout->addWidget(muteButton);
          layout->addWidget(volumeSlider);
          layout->addWidget(rateBox);
          setLayout(layout);
      }

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

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

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

      int PlayerControls::volume() const
      {
          qreal linearVolume =  QAudio::convertVolume(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);

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

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

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

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

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

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

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

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

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

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

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