waveform.cpp Example File

multimedia/spectrum/app/waveform.cpp
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#include "waveform.h" #include "utils.h" #include <QPainter> #include <QResizeEvent> #include <QDebug> //#define PAINT_EVENT_TRACE #ifdef PAINT_EVENT_TRACE # define WAVEFORM_PAINT_DEBUG qDebug() #else # define WAVEFORM_PAINT_DEBUG nullDebug() #endif Waveform::Waveform(QWidget *parent) : QWidget(parent) , m_bufferPosition(0) , m_bufferLength(0) , m_audioPosition(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_PAINT_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_PAINT_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_PAINT_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_PAINT_DEBUG << "Waveform::paintEvent" << "pos ->" << pos; } else { // Reached end of tile array WAVEFORM_PAINT_DEBUG << "Waveform::paintEvent" << "reached end of tile array"; break; } } else { // Passed last tile which is painted WAVEFORM_PAINT_DEBUG << "Waveform::paintEvent" << "tile" << point.index << "not painted"; break; } } else { // pos is past end of tile array WAVEFORM_PAINT_DEBUG << "Waveform::paintEvent" << "pos" << pos << "past end of tile array"; break; } } WAVEFORM_PAINT_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 << "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_bufferPosition = 0; m_buffer = QByteArray(); m_audioPosition = 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::bufferChanged(qint64 position, qint64 length, const QByteArray &buffer) { WAVEFORM_DEBUG << "Waveform::bufferChanged" << "audioPosition" << m_audioPosition << "bufferPosition" << position << "bufferLength" << length; m_bufferPosition = position; m_bufferLength = length; m_buffer = buffer; paintTiles(); } void Waveform::audioPositionChanged(qint64 position) { WAVEFORM_DEBUG << "Waveform::audioPositionChanged" << "audioPosition" << position << "bufferPosition" << m_bufferPosition << "bufferLength" << m_bufferLength; if (position >= m_bufferPosition) { if (position + m_windowLength > m_bufferPosition + m_bufferLength) position = qMax(qint64(0), m_bufferPosition + m_bufferLength - m_windowLength); m_audioPosition = 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; } } 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 tileStart = m_tileArrayStart + i * m_tileLength; const qint64 tileEnd = tileStart + m_tileLength; if (m_bufferPosition <= tileStart && m_bufferPosition + m_bufferLength >= tileEnd) { paintTile(i); updateRequired = true; } } } if (updateRequired) update(); return updateRequired; } void Waveform::paintTile(int index) { const qint64 tileStart = m_tileArrayStart + index * m_tileLength; WAVEFORM_DEBUG << "Waveform::paintTile" << "index" << index << "bufferPosition" << m_bufferPosition << "bufferLength" << m_bufferLength << "start" << tileStart << "end" << tileStart + m_tileLength; Q_ASSERT(m_bufferPosition <= tileStart); Q_ASSERT(m_bufferPosition + m_bufferLength >= 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 - m_bufferPosition) / 2); const int numSamples = m_tileLength / (2 * m_format.channelCount()); 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.channelCount()); // 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.channelCount(); const int offset = reinterpret_cast<const char*>(ptr) - m_buffer.constData(); Q_ASSERT(offset >= 0); Q_ASSERT(offset < m_bufferLength); Q_UNUSED(offset); const qint16 pcmValue = *ptr; const qreal realValue = pcmToReal(pcmValue); const int x = tilePixelOffset(i * 2 * m_format.channelCount()); 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; }

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