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40
41 #ifndef WAVEFORM_H
42 #define WAVEFORM_H
43
44 #include <QWidget>
45 #include <QtMultimedia/QAudioFormat>
46 #include <QPixmap>
47 #include <QScopedPointer>
48
QT_FORWARD_DECLARE_CLASS(QByteArray)49 QT_FORWARD_DECLARE_CLASS(QByteArray)
50
51 /**
52 * Widget which displays a section of the audio waveform.
53 *
54 * The waveform is rendered on a set of QPixmaps which form a group of tiles
55 * whose extent covers the widget. As the audio position is updated, these
56 * tiles are scrolled from left to right; when the left-most tile scrolls
57 * outside the widget, it is moved to the right end of the tile array and
58 * painted with the next section of the waveform.
59 */
60 class Waveform : public QWidget {
61 Q_OBJECT
62 public:
63 Waveform(QWidget *parent = 0);
64 ~Waveform();
65
66 // QWidget
67 void paintEvent(QPaintEvent *event);
68 void resizeEvent(QResizeEvent *event);
69
70 void initialize(const QAudioFormat &format, qint64 audioBufferSize, qint64 windowDurationUs);
71 void reset();
72
73 void setAutoUpdatePosition(bool enabled);
74
75 public slots:
76 void bufferChanged(qint64 position, qint64 length, const QByteArray &buffer);
77 void audioPositionChanged(qint64 position);
78
79 private:
80 static const int NullIndex = -1;
81
82 void deletePixmaps();
83
84 /*
85 * (Re)create all pixmaps, repaint and update the display.
86 * Triggers an update();
87 */
88 void createPixmaps(const QSize &newSize);
89
90 /*
91 * Update window position.
92 * Triggers an update().
93 */
94 void setWindowPosition(qint64 position);
95
96 /*
97 * Base position of tile
98 */
99 qint64 tilePosition(int index) const;
100
101 /*
102 * Structure which identifies a point within a given
103 * tile.
104 */
105 struct TilePoint
106 {
107 TilePoint(int idx = 0, qint64 pos = 0, qint64 pix = 0)
108 : index(idx), positionOffset(pos), pixelOffset(pix)
109 { }
110
111 // Index of tile
112 int index;
113
114 // Number of bytes from start of tile
115 qint64 positionOffset;
116
117 // Number of pixels from left of corresponding pixmap
118 int pixelOffset;
119 };
120
121 /*
122 * Convert position in m_buffer into a tile index and an offset in pixels
123 * into the corresponding pixmap.
124 *
125 * \param position Offset into m_buffer, in bytes
126
127 * If position is outside the tile array, index is NullIndex and
128 * offset is zero.
129 */
130 TilePoint tilePoint(qint64 position) const;
131
132 /*
133 * Convert offset in bytes into a tile into an offset in pixels
134 * within that tile.
135 */
136 int tilePixelOffset(qint64 positionOffset) const;
137
138 /*
139 * Convert offset in bytes into the window into an offset in pixels
140 * within the widget rect().
141 */
142 int windowPixelOffset(qint64 positionOffset) const;
143
144 /*
145 * Paint all tiles which can be painted.
146 * \return true iff update() was called
147 */
148 bool paintTiles();
149
150 /*
151 * Paint the specified tile
152 *
153 * \pre Sufficient data is available to completely paint the tile, i.e.
154 * m_dataLength is greater than the upper bound of the tile.
155 */
156 void paintTile(int index);
157
158 /*
159 * Move the first n tiles to the end of the array, and mark them as not
160 * painted.
161 */
162 void shuffleTiles(int n);
163
164 /*
165 * Reset tile array
166 */
167 void resetTiles(qint64 newStartPos);
168
169 private:
170 qint64 m_bufferPosition;
171 qint64 m_bufferLength;
172 QByteArray m_buffer;
173
174 qint64 m_audioPosition;
175 QAudioFormat m_format;
176
177 bool m_active;
178
179 QSize m_pixmapSize;
180 QVector<QPixmap*> m_pixmaps;
181
182 struct Tile {
183 // Pointer into parent m_pixmaps array
184 QPixmap* pixmap;
185
186 // Flag indicating whether this tile has been painted
187 bool painted;
188 };
189
190 QVector<Tile> m_tiles;
191
192 // Length of audio data in bytes depicted by each tile
193 qint64 m_tileLength;
194
195 // Position in bytes of the first tile, relative to m_buffer
196 qint64 m_tileArrayStart;
197
198 qint64 m_windowPosition;
199 qint64 m_windowLength;
200
201 };
202
203 #endif // WAVEFORM_H
204