diff options
Diffstat (limited to 'examples/multimedia/spectrum/app/waveform.h')
| -rw-r--r-- | examples/multimedia/spectrum/app/waveform.h | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/examples/multimedia/spectrum/app/waveform.h b/examples/multimedia/spectrum/app/waveform.h new file mode 100644 index 000000000..019e86ac5 --- /dev/null +++ b/examples/multimedia/spectrum/app/waveform.h @@ -0,0 +1,202 @@ +/**************************************************************************** +** +** Copyright (C) 2012 Digia Plc and/or its subsidiary(-ies). +** Contact: http://www.qt-project.org/legal +** +** This file is part of the examples of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:BSD$ +** 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 Digia Plc and its Subsidiary(-ies) 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." +** +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#ifndef WAVEFORM_H +#define WAVEFORM_H + +#include <QAudioFormat> +#include <QPixmap> +#include <QScopedPointer> +#include <QWidget> + +/** + * Widget which displays a section of the audio waveform. + * + * The waveform is rendered on a set of QPixmaps which form a group of tiles + * whose extent covers the widget. As the audio position is updated, these + * tiles are scrolled from left to right; when the left-most tile scrolls + * outside the widget, it is moved to the right end of the tile array and + * painted with the next section of the waveform. + */ +class Waveform : public QWidget +{ + Q_OBJECT + +public: + explicit Waveform(QWidget *parent = 0); + ~Waveform(); + + // QWidget + void paintEvent(QPaintEvent *event); + void resizeEvent(QResizeEvent *event); + + void initialize(const QAudioFormat &format, qint64 audioBufferSize, qint64 windowDurationUs); + void reset(); + + void setAutoUpdatePosition(bool enabled); + +public slots: + void bufferChanged(qint64 position, qint64 length, const QByteArray &buffer); + void audioPositionChanged(qint64 position); + +private: + static const int NullIndex = -1; + + void deletePixmaps(); + + /* + * (Re)create all pixmaps, repaint and update the display. + * Triggers an update(); + */ + void createPixmaps(const QSize &newSize); + + /* + * Update window position. + * Triggers an update(). + */ + void setWindowPosition(qint64 position); + + /* + * Base position of tile + */ + qint64 tilePosition(int index) const; + + /* + * Structure which identifies a point within a given + * tile. + */ + struct TilePoint + { + TilePoint(int idx = 0, qint64 pos = 0, qint64 pix = 0) + : index(idx), positionOffset(pos), pixelOffset(pix) + { } + + // Index of tile + int index; + + // Number of bytes from start of tile + qint64 positionOffset; + + // Number of pixels from left of corresponding pixmap + int pixelOffset; + }; + + /* + * Convert position in m_buffer into a tile index and an offset in pixels + * into the corresponding pixmap. + * + * \param position Offset into m_buffer, in bytes + + * If position is outside the tile array, index is NullIndex and + * offset is zero. + */ + TilePoint tilePoint(qint64 position) const; + + /* + * Convert offset in bytes into a tile into an offset in pixels + * within that tile. + */ + int tilePixelOffset(qint64 positionOffset) const; + + /* + * Convert offset in bytes into the window into an offset in pixels + * within the widget rect(). + */ + int windowPixelOffset(qint64 positionOffset) const; + + /* + * Paint all tiles which can be painted. + * \return true iff update() was called + */ + bool paintTiles(); + + /* + * Paint the specified tile + * + * \pre Sufficient data is available to completely paint the tile, i.e. + * m_dataLength is greater than the upper bound of the tile. + */ + void paintTile(int index); + + /* + * Move the first n tiles to the end of the array, and mark them as not + * painted. + */ + void shuffleTiles(int n); + + /* + * Reset tile array + */ + void resetTiles(qint64 newStartPos); + +private: + qint64 m_bufferPosition; + qint64 m_bufferLength; + QByteArray m_buffer; + + qint64 m_audioPosition; + QAudioFormat m_format; + + bool m_active; + + QSize m_pixmapSize; + QVector<QPixmap*> m_pixmaps; + + struct Tile { + // Pointer into parent m_pixmaps array + QPixmap* pixmap; + + // Flag indicating whether this tile has been painted + bool painted; + }; + + QVector<Tile> m_tiles; + + // Length of audio data in bytes depicted by each tile + qint64 m_tileLength; + + // Position in bytes of the first tile, relative to m_buffer + qint64 m_tileArrayStart; + + qint64 m_windowPosition; + qint64 m_windowLength; +}; + +#endif // WAVEFORM_H |