+#ifndef COMPRESSION_REDUCTION_METER_H
+#define COMPRESSION_REDUCTION_METER_H
+
+// A meter that goes downwards instead of upwards, and has a non-linear scale.
+
+#include <math.h>
+#include <QPixmap>
+#include <QString>
+#include <QWidget>
+#include <mutex>
+
+#include "piecewise_interpolator.h"
+
+class QObject;
+class QPaintEvent;
+class QResizeEvent;
+
+class CompressionReductionMeter : public QWidget
+{
+ Q_OBJECT
+
+public:
+ CompressionReductionMeter(QWidget *parent);
+
+ void set_reduction_db(float level_db) {
+ std::unique_lock<std::mutex> lock(level_mutex);
+ this->level_db = level_db;
+ QMetaObject::invokeMethod(this, "update", Qt::AutoConnection);
+ }
+
+private:
+ void resizeEvent(QResizeEvent *event) override;
+ void paintEvent(QPaintEvent *event) override;
+ void recalculate_pixmaps();
+ void draw_scale(QPainter *painter, int x_pos);
+ double db_to_pos(double db) const;
+ int meter_height() const;
+
+ std::mutex level_mutex;
+ float level_db = 0.0f;
+
+ static constexpr float min_level = 0.0f; // Must match control_points (in the .cpp file).
+ static constexpr float max_level = 6.0f; // Same.
+ static constexpr int meter_width = 20;
+
+ // Size of the text box. The meter will be shrunk to make room for the text box
+ // (half the height) on both sides.
+ static constexpr int text_box_width = 15;
+ static constexpr int text_box_height = 10;
+
+ QPixmap on_pixmap, off_pixmap;
+};
+
+#endif