The Control and ControlList uses the raw value (eg. coefficient for gain,
Hz for frequencies) and those Lists are stored in existing sessions.
In the vast majority of cases interpolating automation values using exp/log
scale for dB, freq makes more sense -- it's also what the fader does.
Adding additional interpolation methods is future proof (we might at allow
to even add different methods per automation point (to the next) like other
DAWs do.
Currently it's mainly used in preparation for consistent GUI automation-
lanes. Between 2 points there's always a visual straight line.
This explicit case should never have existed in the first place.
Plugins can always implicitly exceed the range and are expected to
cope with out-of-range values (e.g. meters when fed with a peaking signal
may return an out-of-bounds value)
This allows complete mathematical description of a given parameter
and parameter values.
Semantic type abstraction is reserved for Ardour::ParameterDescriptor.
Functions formerly in ardour/util.h and some more functions.
The main motivation is libevoral which can use libpbd but not libardour.
The eventual goal is to consolidate various different interpolation,
scaling and deflection methods.
Trim automation is planned via SlavableAC as normal AutomationMode.
Some of this code have a revival (a special "Trim+Preview" state
before merging Automation but that has to be more general than Pan & Gain.
Cloning a region retains the region-lock style.
Playlist partitioning set the region start-property only (audio-time).
If a MIDI region is locked to musical-time, Properties::start is ignored
and overwritten by Properties::start_beats.
* The UI and ctrl-surface controls use and display the combined value,
including control-masters.
* The Automation lane of a control is the raw value of the control
without masters.
When touching (or writing) automation, the control-master needs to be
factored out (or subtracted). e.g press+hold a control -> write inverse
master automation.
This went unnoticed because: VCA gain automation was always applied
(regardless of automation state) but when it was not playing
master_ratio() factored it out again (per block).
* remember master-ctrl value on assignment & save with session
* Control/AutomationCtrl only stores ctrl's own value (w/o master)
* virtual AutomationControl::get_value () -> use SlavableAC method
* MasterRecord uses weak-ptr (fixes recursive ~Controllable() deadlock)
