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#include "waveform.h"

#include "utils.h"

#include <QPainter>

#include <QResizeEvent>

#include <QDebug>

Waveform::Waveform(const QByteArray &buffer, QWidget *parent)

    :   QWidget(parent)

    ,   m_buffer(buffer)

    ,   m_dataLength(0)

    ,   m_position(0)

    ,   m_active(false)

    ,   m_tileLength(0)

    ,   m_tileArrayStart(0)

    ,   m_windowPosition(0)

    ,   m_windowLength(0)

{

    setSizePolicy(QSizePolicy::Preferred, QSizePolicy::Fixed);

    setMinimumHeight(50);

}

Waveform::~Waveform()

{

    deletePixmaps();

}

void Waveform::paintEvent(QPaintEvent * /*event*/)

{

    QPainter painter(this);

    painter.fillRect(rect(), Qt::black);

    if (m_active) {

        WAVEFORM_DEBUG << "Waveform::paintEvent"

                       << "windowPosition" << m_windowPosition

                       << "windowLength" << m_windowLength;

        qint64 pos = m_windowPosition;

        const qint64 windowEnd = m_windowPosition + m_windowLength;

        int destLeft = 0;

        int destRight = 0;

        while (pos < windowEnd) {

            const TilePoint point = tilePoint(pos);

            WAVEFORM_DEBUG << "Waveform::paintEvent" << "pos" << pos

                           << "tileIndex" << point.index

                           << "positionOffset" << point.positionOffset

                           << "pixelOffset" << point.pixelOffset;

            if (point.index != NullIndex) {

                const Tile &tile = m_tiles[point.index];

                if (tile.painted) {

                    const qint64 sectionLength = qMin((m_tileLength - point.positionOffset),

                                                     (windowEnd - pos));

                    Q_ASSERT(sectionLength > 0);

                    const int sourceRight = tilePixelOffset(point.positionOffset + sectionLength);

                    destRight = windowPixelOffset(pos - m_windowPosition + sectionLength);

                    QRect destRect = rect();

                    destRect.setLeft(destLeft);

                    destRect.setRight(destRight);

                    QRect sourceRect(QPoint(), m_pixmapSize);

                    sourceRect.setLeft(point.pixelOffset);

                    sourceRect.setRight(sourceRight);

                    WAVEFORM_DEBUG << "Waveform::paintEvent" << "tileIndex" << point.index

                                   << "source" << point.pixelOffset << sourceRight

                                   << "dest" << destLeft << destRight;

                    painter.drawPixmap(destRect, *tile.pixmap, sourceRect);

                    destLeft = destRight;

                    if (point.index < m_tiles.count()) {

                        pos = tilePosition(point.index + 1);

                        WAVEFORM_DEBUG << "Waveform::paintEvent" << "pos ->" << pos;

                    } else {

                        // Reached end of tile array

                        WAVEFORM_DEBUG << "Waveform::paintEvent" << "reached end of tile array";

                        break;

                    }

                } else {

                    // Passed last tile which is painted

                    WAVEFORM_DEBUG << "Waveform::paintEvent" << "tile" << point.index << "not painted";

                    break;

                }

            } else {

                // pos is past end of tile array

                WAVEFORM_DEBUG << "Waveform::paintEvent" << "pos" << pos << "past end of tile array";

                break;

            }

        }

        WAVEFORM_DEBUG << "Waveform::paintEvent" << "final pos" << pos << "final x" << destRight;

    }

}

void Waveform::resizeEvent(QResizeEvent *event)

{

    if (event->size() != event->oldSize())

        createPixmaps(event->size());

}

void Waveform::initialize(const QAudioFormat &format, qint64 audioBufferSize, qint64 windowDurationUs)

{

    WAVEFORM_DEBUG << "Waveform::initialize"

                   << "audioBufferSize" << audioBufferSize

                   << "m_buffer.size()" << m_buffer.size()

                   << "windowDurationUs" << windowDurationUs;

    reset();

    m_format = format;

    // Calculate tile size

    m_tileLength = audioBufferSize;

    // Calculate window size

    m_windowLength = audioLength(m_format, windowDurationUs);

    // Calculate number of tiles required

    int nTiles;

    if (m_tileLength > m_windowLength) {

        nTiles = 2;

    } else {

        nTiles = m_windowLength / m_tileLength + 1;

        if (m_windowLength % m_tileLength)

            ++nTiles;

    }

    WAVEFORM_DEBUG << "Waveform::initialize"

                   << "tileLength" << m_tileLength

                   << "windowLength" << m_windowLength

                   << "nTiles" << nTiles;

    m_pixmaps.fill(0, nTiles);

    m_tiles.resize(nTiles);

    createPixmaps(rect().size());

    m_active = true;

}

void Waveform::reset()

{

    WAVEFORM_DEBUG << "Waveform::reset";

    m_dataLength = 0;

    m_position = 0;

    m_format = QAudioFormat();

    m_active = false;

    deletePixmaps();

    m_tiles.clear();

    m_tileLength = 0;

    m_tileArrayStart = 0;

    m_windowPosition = 0;

    m_windowLength = 0;

}

void Waveform::dataLengthChanged(qint64 length)

{

    WAVEFORM_DEBUG << "Waveform::dataLengthChanged" << length;

    const qint64 oldLength = m_dataLength;

    m_dataLength = length;

    if (m_active) {

        if (m_dataLength < oldLength)

            positionChanged(m_dataLength);

        else

            paintTiles();

    }

}

void Waveform::positionChanged(qint64 position)

{

    WAVEFORM_DEBUG << "Waveform::positionChanged" << position;

    if (position + m_windowLength > m_dataLength)

        position = m_dataLength - m_windowLength;

    m_position = position;

    setWindowPosition(position);

}

void Waveform::deletePixmaps()

{

    QPixmap *pixmap;

    foreach (pixmap, m_pixmaps)

        delete pixmap;

    m_pixmaps.clear();

}

void Waveform::createPixmaps(const QSize &widgetSize)

{

    m_pixmapSize = widgetSize;

    m_pixmapSize.setWidth(qreal(widgetSize.width()) * m_tileLength / m_windowLength);

    WAVEFORM_DEBUG << "Waveform::createPixmaps"

                   << "widgetSize" << widgetSize

                   << "pixmapSize" << m_pixmapSize;

    Q_ASSERT(m_tiles.count() == m_pixmaps.count());

    // (Re)create pixmaps

    for (int i=0; i<m_pixmaps.size(); ++i) {

        delete m_pixmaps[i];

        m_pixmaps[i] = 0;

        m_pixmaps[i] = new QPixmap(m_pixmapSize);

    }

    // Update tile pixmap pointers, and mark for repainting

    for (int i=0; i<m_tiles.count(); ++i) {

        m_tiles[i].pixmap = m_pixmaps[i];

        m_tiles[i].painted = false;

    }

    paintTiles();

}

void Waveform::setWindowPosition(qint64 position)

{

    WAVEFORM_DEBUG << "Waveform::setWindowPosition"

                   << "old" << m_windowPosition << "new" << position

                   << "tileArrayStart" << m_tileArrayStart;

    const qint64 oldPosition = m_windowPosition;

    m_windowPosition = position;

    if((m_windowPosition >= oldPosition) &&

        (m_windowPosition - m_tileArrayStart < (m_tiles.count() * m_tileLength))) {

        // Work out how many tiles need to be shuffled

        const qint64 offset = m_windowPosition - m_tileArrayStart;

        const int nTiles = offset / m_tileLength;

        shuffleTiles(nTiles);

    } else {

        resetTiles(m_windowPosition);

    }

    if(!paintTiles() && m_windowPosition != oldPosition)

        update();

}

qint64 Waveform::tilePosition(int index) const

{

    return m_tileArrayStart + index * m_tileLength;

}

Waveform::TilePoint Waveform::tilePoint(qint64 position) const

{

    TilePoint result;

    if (position >= m_tileArrayStart) {

        const qint64 tileArrayEnd = m_tileArrayStart + m_tiles.count() * m_tileLength;

        if (position < tileArrayEnd) {

            const qint64 offsetIntoTileArray = position - m_tileArrayStart;

            result.index = offsetIntoTileArray / m_tileLength;

            Q_ASSERT(result.index >= 0 && result.index <= m_tiles.count());

            result.positionOffset = offsetIntoTileArray % m_tileLength;

            result.pixelOffset = tilePixelOffset(result.positionOffset);

            Q_ASSERT(result.pixelOffset >= 0 && result.pixelOffset <= m_pixmapSize.width());

        }

    }

    return result;

}

int Waveform::tilePixelOffset(qint64 positionOffset) const

{

    Q_ASSERT(positionOffset >= 0 && positionOffset <= m_tileLength);

    const int result = (qreal(positionOffset) / m_tileLength) * m_pixmapSize.width();

    return result;

}

int Waveform::windowPixelOffset(qint64 positionOffset) const

{

    Q_ASSERT(positionOffset >= 0 && positionOffset <= m_windowLength);

    const int result = (qreal(positionOffset) / m_windowLength) * rect().width();

    return result;

}

bool Waveform::paintTiles()

{

    WAVEFORM_DEBUG << "Waveform::paintTiles";

    bool updateRequired = false;

    for (int i=0; i<m_tiles.count(); ++i) {

        const Tile &tile = m_tiles[i];

        if (!tile.painted) {

            const qint64 tileEnd = m_tileArrayStart + (i + 1) * m_tileLength;

            if (m_dataLength >= tileEnd) {

                paintTile(i);

                updateRequired = true;

            }

        }

    }

    if (updateRequired)

        update();

    return updateRequired;

}

void Waveform::paintTile(int index)

{

    WAVEFORM_DEBUG << "Waveform::paintTile" << "index" << index;

    const qint64 tileStart = m_tileArrayStart + index * m_tileLength;

    Q_ASSERT(m_dataLength >= tileStart + m_tileLength);

    Tile &tile = m_tiles[index];

    Q_ASSERT(!tile.painted);

    const qint16* base = reinterpret_cast<const qint16*>(m_buffer.constData());

    const qint16* buffer = base + (tileStart / 2);

    const int numSamples = m_tileLength / (2 * m_format.channels());

    QPainter painter(tile.pixmap);

    painter.fillRect(tile.pixmap->rect(), Qt::black);

    QPen pen(Qt::white);

    painter.setPen(pen);

    // Calculate initial PCM value

    qint16 previousPcmValue = 0;

    if (buffer > base)

        previousPcmValue = *(buffer - m_format.channels());

    // Calculate initial point

    const qreal previousRealValue = pcmToReal(previousPcmValue);

    const int originY = ((previousRealValue + 1.0) / 2) * m_pixmapSize.height();

    const QPoint origin(0, originY);

    QLine line(origin, origin);

    for (int i=0; i<numSamples; ++i) {

        const qint16* ptr = buffer + i * m_format.channels();

        const qint16 pcmValue = *ptr;

        const qreal realValue = pcmToReal(pcmValue);

        const int x = tilePixelOffset(i * 2 * m_format.channels());

        const int y = ((realValue + 1.0) / 2) * m_pixmapSize.height();

        line.setP2(QPoint(x, y));

        painter.drawLine(line);

        line.setP1(line.p2());

    }

    tile.painted = true;

}

void Waveform::shuffleTiles(int n)

{

    WAVEFORM_DEBUG << "Waveform::shuffleTiles" << "n" << n;

    while (n--) {

        Tile tile = m_tiles.first();

        tile.painted = false;

        m_tiles.erase(m_tiles.begin());

        m_tiles += tile;

        m_tileArrayStart += m_tileLength;

    }

    WAVEFORM_DEBUG << "Waveform::shuffleTiles" << "tileArrayStart" << m_tileArrayStart;

}

void Waveform::resetTiles(qint64 newStartPos)

{

    WAVEFORM_DEBUG << "Waveform::resetTiles" << "newStartPos" << newStartPos;

    QVector<Tile>::iterator i = m_tiles.begin();

    for ( ; i != m_tiles.end(); ++i)

        i->painted = false;

    m_tileArrayStart = newStartPos;

}