diff options
Diffstat (limited to 'gtk2_ardour/logmeter.h')
-rw-r--r-- | gtk2_ardour/logmeter.h | 49 |
1 files changed, 49 insertions, 0 deletions
diff --git a/gtk2_ardour/logmeter.h b/gtk2_ardour/logmeter.h new file mode 100644 index 0000000000..f7ed1dd2be --- /dev/null +++ b/gtk2_ardour/logmeter.h @@ -0,0 +1,49 @@ +#ifndef __ardour_gtk_log_meter_h__ +#define __ardour_gtk_log_meter_h__ + +#if 0 +inline float +_log_meter (float power, double lower_db, double upper_db, double non_linearity) +{ + return (power < lower_db ? 0.0 : pow((power-lower_db)/(upper_db-lower_db), non_linearity)); +} + +inline float +log_meter (float power) +{ + return _log_meter (power, -192.0, 0.0, 8.0); +} +#endif + +inline float +log_meter (float db) +{ + gfloat def = 0.0f; /* Meter deflection %age */ + + if (db < -70.0f) { + def = 0.0f; + } else if (db < -60.0f) { + def = (db + 70.0f) * 0.25f; + } else if (db < -50.0f) { + def = (db + 60.0f) * 0.5f + 2.5f; + } else if (db < -40.0f) { + def = (db + 50.0f) * 0.75f + 7.5f; + } else if (db < -30.0f) { + def = (db + 40.0f) * 1.5f + 15.0f; + } else if (db < -20.0f) { + def = (db + 30.0f) * 2.0f + 30.0f; + } else if (db < 6.0f) { + def = (db + 20.0f) * 2.5f + 50.0f; + } else { + def = 115.0f; + } + + /* 115 is the deflection %age that would be + when db=6.0. this is an arbitrary + endpoint for our scaling. + */ + + return def/115.0f; +} + +#endif /* __ardour_gtk_log_meter_h__ */ |