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Diffstat (limited to 'examples/multimedia/spectrum/waveform.cpp')
| -rw-r--r-- | examples/multimedia/spectrum/waveform.cpp | 400 |
1 files changed, 400 insertions, 0 deletions
diff --git a/examples/multimedia/spectrum/waveform.cpp b/examples/multimedia/spectrum/waveform.cpp new file mode 100644 index 000000000..a3727a2a6 --- /dev/null +++ b/examples/multimedia/spectrum/waveform.cpp @@ -0,0 +1,400 @@ +// Copyright (C) 2017 The Qt Company Ltd. +// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause + +#include "waveform.h" +#include "utils.h" + +#include <QDebug> +#include <QPainter> +#include <QResizeEvent> + +//#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 = m_format.bytesForDuration(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(nullptr, 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() +{ + qDeleteAll(std::exchange(m_pixmaps, {})); +} + +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 (auto &pixmap : m_pixmaps) { + delete pixmap; + pixmap = 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; + + QList<Tile>::iterator i = m_tiles.begin(); + for (; i != m_tiles.end(); ++i) + i->painted = false; + + m_tileArrayStart = newStartPos; +} + +#include "moc_waveform.cpp" |