Program Changes are stored as an offset from the 'source' start, and must be translated to/from region time.
Better locating of patches wrt the grid:
You can't assume time_to_pixel is steady across the timeline
* calculate position of the patch-change flag
* calculate region start position, and set flag's x offset from there
also: consolidate patch-location code into display_patch_changes()
max_samplepos and max_samplecnt and both INT64_MAX which is (a) too large to fit into a signed 62 bit
integer and (b) definitely too large to be represented in a signed 62 bit superclock value.
Move the constructors that use samplepos_t into the .cc file, and treat these two values as special
cases that mean "as large/late/huge/long as possible".
This works around a race-condition, calling d'tors from
two threads concurrently.
The GUI thread destroys ctrl surfaces. ~~MIDIControllable()
calls ::drop_external_control() -> ::midi_forget()
This unsubscribes from signals (notably MIDI::Parser events)
by calling ScopedConnection::disconnect(), Connection::disconnect().
At the same time auto_connect_thread can call
PortManager::clear_pending_port_deletions() which removes
the MIDI port and destorys the MIDI::Parser.
~Parser() calls Connection::signal_going_away() to invalidate
connected signals.
This can deadlock if it is called concurrently with
Connection::disconnect() on the same signal.
see also
https://discourse.ardour.org/t/ardour-session-close-hangs/106523/10
When adding a note, use these criteria to choose the channel number:
* if the user has explicitly specified a note in the pulldown, use that
* if the user has AUTO selected and we are in a region, choose the nearest note's channel (consistent with velocity behavior)
* as a fallback, query the track for its channel-filter (old behavior)
Instead of just restarting it inside the same ::run() call, mark it as waiting,
so that it will restart at the next quantization point.
This isn't a final or even fully correct solution, but it's a useful test of
the idea.
The old code used the instantaneous tempo at T0 to compute where the next
quarter note would be. This is incorrect, since the tempo is
changing (continuously, for now) during the time represented by that quarter
note. Instead, we need to add a quarter note (or technically, whatever the
tempo note type is) to get a new position in beats, then compute the superclock
time at that location (which will use our equations for tempo, including the
use of omega, the ramp factor).
The objects referenced by markers point to the copy of the map held by the per-thread ptr. But
the edits must be done on a writable copy of the map. ::reassociate_metric_markers() fixes
the references to use the writable copy, so that when we pass references to the objects in the map
to the writable copy, it will find them and modify them (rather then ones in the previous
generation of the tempo map)
