waveform.h Example File

/**************************************************************************** ** ** Copyright (C) 2017 The Qt Company Ltd. ** Contact: https://www.qt.io/licensing/ ** ** This file is part of the examples of the Qt Toolkit. ** ** $QT_BEGIN_LICENSE:BSD$ ** Commercial License Usage ** Licensees holding valid commercial Qt licenses may use this file in ** accordance with the commercial license agreement provided with the ** Software or, alternatively, in accordance with the terms contained in ** a written agreement between you and The Qt Company. For licensing terms ** and conditions see https://www.qt.io/terms-conditions. For further ** information use the contact form at https://www.qt.io/contact-us. ** ** BSD License Usage ** Alternatively, 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 The Qt Company Ltd 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) override; void resizeEvent(QResizeEvent *event) override; 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

© 2020 The Qt Company Ltd. Documentation contributions included herein are the copyrights of their respective owners. The documentation provided herein is licensed under the terms of the GNU Free Documentation License version 1.3 as published by the Free Software Foundation. Qt and respective logos are trademarks of The Qt Company Ltd. in Finland and/or other countries worldwide. All other trademarks are property of their respective owners.