source: trunk/src/3rdparty/phonon/ds9/audiooutput.cpp

/*  This file is part of the KDE project.

Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

This library is free software: you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation, either version 2.1 or 3 of the License.

This library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License
along with this library.  If not, see <http://www.gnu.org/licenses/>.
*/

#include "audiooutput.h"
#include "mediaobject.h"

#include <QtCore/qmath.h>

QT_BEGIN_NAMESPACE

namespace Phonon
{
    namespace DS9
    {
        AudioOutput::AudioOutput(Backend *back, QObject *parent)
            : BackendNode(parent), m_currentIndex(0), m_crossfadeProgress(1.),
              m_device(-1), m_backend(back), m_volume(0.)
        {
        }

        AudioOutput::~AudioOutput()
        {
        }

        int AudioOutput::outputDevice() const
        {
            return m_device;
        }

        static const qreal log10over20 = qreal(0.1151292546497022842); // ln(10) / 20

        void AudioOutput::setVolume(qreal newVolume)
        {
            for(int i = 0; i < FILTER_COUNT; ++i) {
                ComPointer<IBasicAudio> audio(m_filters[i], IID_IBasicAudio);
                if (audio) {
                    const qreal currentVolume = newVolume * (m_currentIndex == i ? m_crossfadeProgress : 1-m_crossfadeProgress);
                    const qreal newDbVolume = (qMax(0., 1.-::log(::pow(currentVolume, -log10over20)))-1.) * 10000;
                    audio->put_Volume(qRound(newDbVolume));
                }
            }

            if (m_volume != newVolume) {
                m_volume = newVolume;
                emit volumeChanged(newVolume);
            }
        }

        void AudioOutput::setCrossFadingProgress(short currentIndex, qreal progress)
        {
            m_crossfadeProgress = progress;
            m_currentIndex = currentIndex;
            setVolume(m_volume);
        }

        bool AudioOutput::setOutputDevice(const AudioOutputDevice & newDevice)
        {
            //stub implementation
            return setOutputDevice(newDevice.index());
        }

        qreal AudioOutput::volume() const
        {
            return m_volume;
        }

        bool AudioOutput::setOutputDevice(int newDevice)
        {
            if (newDevice == m_device) {
                return true;
            }

            //free the previous one if it was already set
            for(int i = 0; i < FILTER_COUNT; ++i) {
                const Filter &oldFilter = m_filters[i];

                Filter newFilter = m_backend->getAudioOutputFilter(newDevice);

                if (m_mediaObject && oldFilter && newFilter) {
                    m_mediaObject->switchFilters(i, oldFilter, newFilter);
                }

                m_filters[i] = newFilter; 


            }

            m_device = newDevice;
            setVolume(m_volume);
            return true;
        }
    }
}

QT_END_NAMESPACE

#include "moc_audiooutput.cpp"