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/****************************************************************************
**
** 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 <QWidget>
#include <QtMultimedia/QAudioFormat>
#include <QPixmap>
#include <QScopedPointer>
QT_FORWARD_DECLARE_CLASS(QByteArray)
/**
* 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:
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
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