diff options
Diffstat (limited to 'gtk2_ardour/volume_controller.cc')
| -rw-r--r-- | gtk2_ardour/volume_controller.cc | 54 |
1 files changed, 52 insertions, 2 deletions
diff --git a/gtk2_ardour/volume_controller.cc b/gtk2_ardour/volume_controller.cc index 27fd705978..6db3bc7d7a 100644 --- a/gtk2_ardour/volume_controller.cc +++ b/gtk2_ardour/volume_controller.cc @@ -142,7 +142,6 @@ VolumeController::adjust (double control_delta) double v; if (!_linear) { - /* we map back into the linear/fractional slider position, * because this kind of control goes all the way down * to -inf dB, and we want this occur in a reasonable way in @@ -150,7 +149,7 @@ VolumeController::adjust (double control_delta) * gain coefficient domain (or dB domain), the lower end of the * control range (getting close to -inf dB) takes forever. */ - +#if 0 /* convert to linear/fractional slider position domain */ v = gain_to_slider_position_with_max (_controllable->get_value (), _controllable->upper()); /* increment in this domain */ @@ -171,6 +170,57 @@ VolumeController::adjust (double control_delta) } /* and return it */ return dB_to_coefficient (v); +#else + /* ^^ Above algorithm is not symmetric. Scroll up to steps, scoll down two steps, -> different gain. + * + * see ./libs/gtkmm2ext/gtkmm2ext/motionfeedback.h and gtk2_ardour/monitor_section.cc: + * min-delta (corr) = MIN(0.01 * page inc, 1 * size_inc) // (gain_control uses size_inc=0.01, page_inc=0.1) + * range corr: 0..2 -> -inf..+6dB + * step sizes [0.01, 0.10, 0.20] * page_inc, [1,2,10,100] * step_inc. [1,2,10,100] * page_inc + * + * 0.001, 0.01, 0.02, 0.1, .2, 1, 10 + * -> 1k steps between -inf..0dB + * -> 1k steps between 0..+dB + * + * IOW: + * the range is from *0 (-inf dB) to *2.0 ( +6dB) + * the knob is configured to to go in steps of 0.001 - that's 2000 steps between 0 and 2. + * or 1000 steps between 0 and 1. + * + * we cannot round to .01dB steps because + * There are only 600 possible values between +0db and +6dB when going in steps of .01dB + * 1000/600 = 1.66666... + * + ****** + * idea: make the 'controllable use a fixed range of dB. + * do a 1:1 mapping between values. :et's stick with the range of 0..2 in 0.001 steps + * + * "-80" becomes 0 and "+6" becomes 2000. (NB +6dB is actually 1995, but we clamp that to the top) + * + * This approach is better (more consistet) but not good. At least the dial does not annoy me as much + * anymore as it did before. + * + * const double stretchfactor = rint((_controllable->upper() - _controllable->lower()) / 0.001); // 2000; + * const double logfactor = stretchfactor / ((20.0 * log10( _controllable->upper())) + 80.0); // = 23.250244732 + */ + v = _controllable->get_value (); + /* assume everything below -60dB is silent (.001 ^= -60dB) + * but map range -80db..+6dB to a scale of 0..2000 + * 80db was motivated because 2000/((20.0 * log(1)) + 80.0) is an integer value. "0dB" is included on the scale. + * but this leaves a dead area at the bottom of the meter.. + */ + double arange = (v >= 0.001) ? ( ((20.0 * log10(v)) + 80.0) * 23.250244732 ) : ( 0 ); + /* add the delta */ + v = rint(arange) + rint(control_delta * 1000.0); // (min steps is 1.0/0.001 == 1000.0) + /* catch bottom -80..-60 db in one step */ + if (v < 466) v = (control_delta > 0) ? 0.001 : 0; + /* reverse operation (pow(10, .05 * ((v / 23.250244732) - 80.0))) + * can be simplified to :*/ + else v = pow(10, (v * 0.00215051499) - 4.0); + /* clamp value in coefficient domain */ + v = std::max (_controllable->lower(), std::min (_controllable->upper(), v)); + return v; +#endif } else { double mult; |