Make the compression meter nonlinear.

[nageru] / compression_reduction_meter.cpp

diff --git a/compression_reduction_meter.cpp b/compression_reduction_meter.cpp
new file mode 100644 (file)
index 0000000..a59a71e
--- /dev/null
+++ b/compression_reduction_meter.cpp
@@ -0,0 +1,100 @@
+#include "compression_reduction_meter.h"
+
+#include <QPainter>
+#include <QRect>
+#include "piecewise_interpolator.h"
+#include "vu_common.h"
+
+class QPaintEvent;
+class QResizeEvent;
+
+using namespace std;
+
+namespace {
+
+vector<PiecewiseInterpolator::ControlPoint> control_points = {
+       { 60.0f, 6.0f },
+       { 30.0f, 5.0f },
+       { 18.0f, 4.0f },
+       { 12.0f, 3.0f },
+       { 6.0f, 2.0f },
+       { 3.0f, 1.0f },
+       { 0.0f, 0.0f }
+};
+PiecewiseInterpolator interpolator(control_points);
+
+}  // namespace
+
+CompressionReductionMeter::CompressionReductionMeter(QWidget *parent)
+       : QWidget(parent)
+{
+}
+
+void CompressionReductionMeter::resizeEvent(QResizeEvent *event)
+{
+       recalculate_pixmaps();
+}
+
+void CompressionReductionMeter::paintEvent(QPaintEvent *event)
+{
+       QPainter painter(this);
+
+       float level_db;
+       {
+               unique_lock<mutex> lock(level_mutex);
+               level_db = this->level_db;
+       }
+
+       int on_pos = lrint(db_to_pos(level_db));
+
+       QRect on_rect(0, 0, width(), on_pos);
+       QRect off_rect(0, on_pos, width(), height());
+
+       painter.drawPixmap(on_rect, on_pixmap, on_rect);
+       painter.drawPixmap(off_rect, off_pixmap, off_rect);
+}
+
+void CompressionReductionMeter::recalculate_pixmaps()
+{
+       constexpr int y_offset = text_box_height / 2;
+       constexpr int text_margin = 5;
+       float margin = 0.5 * (width() - meter_width);
+
+       on_pixmap = QPixmap(width(), height());
+       QPainter on_painter(&on_pixmap);
+       on_painter.fillRect(0, 0, width(), height(), parentWidget()->palette().window());
+       draw_vu_meter(on_painter, width(), meter_height(), margin, 2.0, true, min_level, max_level, /*flip=*/true, y_offset);
+       draw_scale(&on_painter, 0.5 * width() + 0.5 * meter_width + text_margin);
+
+       off_pixmap = QPixmap(width(), height());
+       QPainter off_painter(&off_pixmap);
+       off_painter.fillRect(0, 0, width(), height(), parentWidget()->palette().window());
+       draw_vu_meter(off_painter, width(), meter_height(), margin, 2.0, false, min_level, max_level, /*flip=*/true, y_offset);
+       draw_scale(&off_painter, 0.5 * width() + 0.5 * meter_width + text_margin);
+}
+
+void CompressionReductionMeter::draw_scale(QPainter *painter, int x_pos)
+{
+       QFont font;
+       font.setPointSize(8);
+       painter->setPen(Qt::black);
+       painter->setFont(font);
+       for (size_t i = 0; i < control_points.size(); ++i) {
+               char buf[256];
+               snprintf(buf, 256, "%.0f", control_points[i].db_value);
+               double y = db_to_pos(control_points[i].db_value);
+               painter->drawText(QRect(x_pos, y - text_box_height / 2, text_box_width, text_box_height),
+                       Qt::AlignCenter | Qt::AlignVCenter, buf);
+       }
+}
+
+double CompressionReductionMeter::db_to_pos(double level_db) const
+{
+       float value = interpolator.db_to_fraction(level_db);
+       return height() - lufs_to_pos(value, meter_height(), min_level, max_level) - text_box_height / 2;
+}
+
+int CompressionReductionMeter::meter_height() const
+{
+       return height() - text_box_height;
+}