9 int lufs_to_pos(float level_lu, int height)
11 const float min_level = 9.0f; // y=0 is top of screen, so “min” is the loudest level.
12 const float max_level = -18.0f;
13 int y = lrintf(height * (level_lu - min_level) / (max_level - min_level));
15 y = std::min(y, height - 1);
21 VUMeter::VUMeter(QWidget *parent)
26 void VUMeter::paintEvent(QPaintEvent *event)
28 QPainter painter(this);
30 painter.fillRect(0, 0, width(), height(), Qt::black);
32 // Draw some reference bars.
33 for (int level = -18; level < 9; ++level) {
34 int min_y = lufs_to_pos(level, height()) - 1;
35 int max_y = lufs_to_pos(level + 1.0f, height()) + 1;
37 // Recommended range is 0 LU +/- 1 LU.
38 if (level == -1 || level == 0) {
39 painter.fillRect(1, min_y, width() - 2, max_y - min_y, Qt::green);
41 painter.fillRect(1, min_y, width() - 2, max_y - min_y, Qt::darkGray);
47 unique_lock<mutex> lock(level_mutex);
48 level_lufs = this->level_lufs;
51 float level_lu = level_lufs + 23.0f;
52 int y = lufs_to_pos(level_lu, height());
53 painter.fillRect(0, y, width(), 2, Qt::white);